## Removing IR Filter From ESP32-Cam, Part III

Okay, so it’s been a while but I finally got a chance to tinker with the ESP32-Cam in the dark again. 🙂

I’m using the same kind of IR illuminator that I used last time. You can get them all over the place. These little guys:

I went back over what I’d done last time and looked at my notes that I’d made after. The last time, I thought I’d play it safe and use a constant-current source to power the LED. I’ve had good results in the past using an LM317 to do this quickly and cheaply, so that’s the way I went, limiting the current to 125mA.

Turns out, though, that I was underpowering the illuminator because not only is it capable of more than 125mA, it was only getting around 2.4V because I was powering the LM317 off a 5V supply instead of the 12V I should’ve used.

This time around, I changed how I powered it. After a bit of poking around, it seems the illuminator runs on a 3.3V supply. I wanted to run it off a 5V USB pack because it’s so convenient, so I cheated and just put two 1N4001 diodes in series between +5V and the illuminator to get down to around 3.3V:

I also ended up adding a 1uF tantalum capacitor between the GND and +5V pins of the USB connector to cut down on some of the noise.

There is a tiny potentiometer on the module that supposedly controls at which point the module will turn on the LED, but it seems that it controls the current through the LED and has very little (if anything) to do with the amount of light on the photoresistor. Turning it all the way in one direction (clockwise, I think) gives a current of about 65mA through the LED, while all the way the other direction gives a current of around 420mA.

Unless you attach a heat sink, DO NOT RUN THESE IR ILLUMINATORS AT FULL POWER. It didn’t take too long before I could smell that all too familiar burning electronics smell, and the module itself failed shortly after.

I took another one, covered the photoresistor, and dialed it in to about 300mA. In this case, with unrestricted natural convection, it was able to run for over five hours before I turned it off. It was hot to the touch, but not unbearably so. Yours will probably be different, so keep an eye on it!

Here’s what happened with the current as the time went on:

So in the first 20 minutes or so the current climbed from 295mA to 325mA and then stayed there for the nest four hours and 50 minutes. For the entire time, the voltage across the module was 3.2V:

So, 325mA at 3.2V works out to 1.04W. That’s a lot better than the 0.3W from the previous setup. The advertising for these modules claims 3W, but I think it’s assuming you’re using both at the same time (they all come in 2-packs) and are running them with the pot dialed to full power.

Yes, there are problems with how I did this. Using two diodes isn’t a great way to “set” the voltage. Those USB meters are notorious for being inaccurate, too. So again, if you decide to try this, keep an eye on your stuff!

So the big question then, is: does running the LED at 3.5x the power make much of a difference? I think it does. Here’s a look from the dining room table with the LED covered up…

… and uncovered:

Note that surface C is about six feet from the camera. A is ten feet, and B is about 22 feet. This is noticeably better than the last set of tests – the pictures I took inside the hallway with the closed doors last time confined the IR and kept it bouncing around. In this picture, the room is wide open and the pattern on the wall over 20 feet away is still easy to make out.

Here we are back in the hallway like last time. Here it is without IR:

… and with IR:

For reference, here’s what the camera saw when I did this test back in May:

The picture from today with the illuminator running 3.2V@300mA is noticeably brighter and less grainy. This is a good thing!

And I braved a near-solid wall of mosquitoes to try the ESP32-Cam again outside on the deck steps. Here’s a picture with no IR (it’s a little blurry because I was waving my arms trying to keep from being exsanguinated:

Unfortunately, the bird feeder has moved around the yard a few times since May, so I wasn’t able to use it to compare with last time. However…

… this time I can see THE FENCE. And the garden. And the solar panel in the garden. And the little weather station thing. Even the eavestrough on the neighbour’s house! Here’s what it looked like last time:

Quite the difference! I’m also only using one of the illuminators – they come in pairs. Twice the output won’t correspond to twice the brightness in the camera, but it will certainly lighten things up even more.

The ESP32-Cam with the IR filter removed and this particular illuminator do not put on a stellar performance, but I’m comfortable saying that they works well indoors, and they’re decent outside, too. Not good enough to, say, catch a license plate of a car driving by, but just fine within six to ten feet.

I still plan to put one of these outside, but getting a wifi signal out there is pretty tricky. I’ll either have to move the router or add something else to the network here. That might end up being a whole other project.

Thanks to everyone who commented and sent messages – I appreciate the feedback!

## Removing IR Filter From ESP32-CAM, Part II

**UPDATE (2020-05-08): I did a little bit of math and realized I was only running the IR illuminator at about a quarter of a watt. After a bit more poking around and squinting at part numbers, I’m pretty sure it can run at almost 10x the power. I will look into this further sometime soon.**

Shortly after my previous post on removing the IR-cut filter from the OV2640 camera that comes with the ESP32-CAM, I put the ESP in a safe place… so safe that I lost it.

I found it again a couple of days ago and finally got to tinkering with it this evening, with the plan to see how well it worked in the dark.

I changed the following settings from the defaults for all of the pictures taken with the ESP in this post:
– Frame size: 1024×768 (XGA)
– Gain ceiling set to 3
– Special effect set to 2 (greyscale)

Without the filter, the colours were all wrong and it was a little harder to focus. This is normal but a little annoying, so I set the image to greyscale. Here’s the first image I took, looking at the bird feeder as the sun was on its way down on the other side of the house:

It’s not too bad. Things look a little weird – the trees, sky, and grass all look like they’re from a really cheap dream sequence. Two hours and fifteen minutes later, the sun had set but there was still plenty enough light for the camera:

Twenty minutes later, the streetlights were all on, there was very little glow in the sky, and the image started to get pretty noisy:

Another 25 minutes and it was dark:

So, with ambient light in the suburbs at night, the ESP32-Cam isn’t a stellar performer. This is not a high-end CCD rig.

I have a couple of inexpensive little IR illuminators but they’re so inexpensive that they didn’t come with specifications and I can’t find datasheets for them. I ended up using an LM317 to limit the current to about 125mA. I’m pretty sure they can go higher but figuring out how high is a project for another day.

Here’s what that thing running at 125mA did:

Not so good. Or… was it not too bad? It’s not like I went out there with one of those 400 LED yard illuminators – this was a single diffused LED that’s pulling just over half a watt. Maybe I should revisit this with something that puts out a little more oomph.

The next thing on my list to check was how well it worked indoors. To test this, I put the camera and illuminator at one end of a hallway, closed the door, and turned off all the lights. My phone picked up a bit of light under the door at the far end of the hall, about 12 feet away:

And here’s what the ESP saw:

And with the same illuminator (at the same power) turned on:

Having the IR confined to an area where it can bounce around and not just be lost to the night makes a big difference. With a better (or more than one) source of IR, the ESP32-CAM may well make a decent indoor night camera. Tweaking some of the camera settings may improve things, too.

So… not the best performer, but for the cost (I think I paid nine dollars for this particular one, camera and all) and the sheer number of features that the ESP32 series has, I find it a pretty attractive little device.

I think the next ESP-ish things I want to look at are getting some pictures of the animals that wander through the yard at night, and maybe trying this particular experiment again with a bigger/better IR illuminator.

## Recovering A Lost mdadm RAIDset In A Raspberry Pi-Based RAID Mirror

My previous post went over how to replace a failed USB-attached RAIDset member in a Raspberry Pi system running mdadm. Swapping out a failed RAIDset member is pretty simple, but what if the Pi or the micro SD card in the Pi fails?

Well, good news – mdadm stores metadata on the RAIDset members so even if you lose the RAID configuration on the SD card, you can recover it by scanning the disks.

I’m going to use the same Pi 4 (2GB) and two 64GB SanDisk USB sticks that I used in the previous post. They’re set up as a two disk mirror.

To simulate an SD card failure, I killed power to the Pi without shutting it down gracefully, then removed and re-imaged the card before putting it back into the Pi and powering it up. Here’s how to get your data back.

First things first – flash the appropriate Raspbian image to a micro SD card and set up your Pi like you would normally. Don’t forget to go through raspi-config and do the sudo apt update and sudo apt upgrade thing!

Once your Pi is up and running, fully up to date, and configured the way you like it, then shut it down, reattach the USB drives, and start it up again. Once it’s booted, check dmesg to see if the Pi can see the USB drives. The first USB drive will be called sda, the second will be sdb, and so on:

In my case, I only have two disks, /dev/sda and /dev/sdb and they’re both showing up. If you’re not seeing the disks, check connections and power and fix the problem before going on.

Using cat /proc/mdstat is the easiest way to check the status of your RAID array, but if you run it now, you’ll get nothing:

That’s because mdadm hasn’t been installed yet. Install it with the following:
sudo apt install mdadm

Once it’s installed, scan the disks on or attached to the Pi and create a RAIDset with any member disks found, using
sudo mdadm --assemble --scan --verbose

Notice that it found both /dev/sda and /dev/sdb, and it added them to an array.

Check the status of the array with cat /proc/mdstat:

It’s showing as [UU], which means both members are online and working properly. The array didn’t even need to resync!

Now, check the /etc/mdadm/mdadm.conf file to see if the configuration has been automatically updated:

Under “definitions of existing MD arrays” you can see the array is showing up. Also notice that it’s still called “DEV-04:0” – DEV-04 was the name of the Pi before I wiped out and rebuilt the SD card, so chances are it has the right data.

Reboot your Pi to see if it (and the array) come up cleanly. This isn’t a necessary step but I like doing it to make sure things are working and I haven’t forgotten anything.

Run blkid to see if /dev/md0 is listed:

So far, so good. Now, edit your /etc/fstab file, adding an entry for /dev/md0 but use the UUID instead of the device name:

I’m using /mnt as the mount point but it can be anywhere you want.

Once you’ve saved the file (and if everything is working properly), you should be able to mount the drive and use it with sudo mount -a

If there are no errors and the system doesn’t hang or do something else weird, things may be working! Run df to see if /dev/md0 is mounted:

Hopefully you’ll see something similar. Check out the mounted directory and see if your data is there:

Depending on how you had things set up, you may need to change or set some permissions, but if it mounts and you can browse to it, that’s a good sign. Reboot the Pi once more to make sure the array and mounting work as expected, and if so, then everything should be good to go!

You can also use this method to move a RAIDset from one machine to another, although you should really, REALLY back up your data before you do that.

Actually, getting a backup of your stuff periodically isn’t a bad idea either. mdadm is mature and pretty stable, but a RAIDset with redundancy is no substitute for backups!

## Replacing A Failed USB Disk In A Raspberry Pi-Based RAID Mirror

My previous post went into how to create a simple but functional NAS with a Raspberry Pi 4B and two USB-attached SATA disks. In the two weeks or so that it’s been running, the NAS I built has performed very well and has been reliable (hopefully I won’t regret typing that).

But what to do WHEN a disk fails? Disks fail – even that fancy new enterprise-grade SSD that cost an arm and a leg will fail at some point. The good news is that if you’re using mdadm to provide some kind of redundancy with your disks, things should still be working if a disk fails. The bad news is that unless you’ve got a RAIDset that can specifically tolerate more than one failure (like RAID 6), you need to replace that failed disk ASAP.

I’m confident that I’ll be able to recover from losing a disk in my shiny new NAS, but I’m not one to tempt fate so I built another RAIDset with a spare Pi and two 64GB SanDisk USB sticks to play around with instead. They’re slower than the disks so things like the speed the RAIDset syncs back up is going to be different than in my previous post.

So here’s the setup – it’s a Raspberry Pi 4B (2GB) with two 64GB USB flash drives in a RAID 0 (mirror) configuration.

Here it is, working properly, with the output of cat /proc/mdstat:

and checking to see if it’s mounted using df:

To simulate a disk failure, I removed one of the USB sticks while everything was running. Here’s the output of dmesg showing the disconnection and that mdadm is soldiering on with only one disk:

Looking at the list of USB-connected devices only shows one SanDisk device:

And now the output of cat /proc/mdstat is showing a failed disk (note the “U_”):

The good news is that yes, /dev/md0 is still mounted and usable, even though it’s in a degraded state.

I reformatted the USB stick on my Windows PC so the data that was on there was lost, then reconnected it to the Pi:

And here’s the output of dmesg again – you can see the time difference between the failure and when the “new” disk was connected:

Note that the messages both of the failure and of the newly connected USB stick show them as sdb. It could just as easily have been sda, so make sure you check to see which one failed – and, more importantly, which one didn’t!

So now there are two disks connected again, but only one of them has the RAIDset data on it. In this case, sda is the one with the data that needs to be mirrored over. Again, it could’ve been sdb. For one last check, get the output of cat /proc/mdstat again:

Notice it says sda – that means that sda has the data we want to mirror over to the other disk, which, as the previous output of dmesg showed, is sdb.

If you are replacing a failed RAID member, the replacement must be the same size or larger than the failed member. That goes for any kind of RAID level and any type (i.e. disk mirroring or partition mirroring). Keep in mind that not all disks of the same stated capacity will actually have the same capacity, so make sure you do a bit of research before going out and spending your money on a new disk that won’t fit your current array!

Now that the disk is reconnected and showing up, copy the partition layout from the existing RAIDset disk to the new disk with the following command:

sudo sfdisk -d /dev/sdX | sudo sfdisk /dev/sdY

In this case, the existing disk is /dev/sda and the new disk is /dev/sdb:

This step isn’t needed if you’re mirroring disks (as opposed to mirroring partitions), but it’s a good idea to do it anyway – if there’s an error here, you certainly don’t want to go any further until you’ve fixed the problem.

If sfdisk worked and didn’t give you any errors, then you’re ready to add the new disk to the RAIDset with the following command:

sudo mdadm --manage /dev/md0 --add /dev/sdY

Where sdY is the new disk – in my case, sdb:

If you didn’t get any errors, run cat /proc/mdstat again and you’ll see your RAIDset is rebuilding:

Notice how it now shows that there are two active elements in md0sdb[2] and sda[0]? That’s a good sign. Keep checking every once in a while to make sure the recovery is progressing.

Once it’s done, the RAIDset should be showing as all “U” again:

If you see that, everything’s rebuilt and your RAIDset is ready to handle another disk failure.

Hopefully you never need to use this information, but if you do, I hope it helps!

## Raspberry Pi 4-Based NAS Using USB-Connected Disks

Our little DNS-323 has been rock solid for the last decade but it’s getting long in the tooth and it’s just pokey enough to be annoying when I’m trying to do things on it. After a bit of consideration, I decided to see if I could build one with a Raspberry Pi.

It didn’t take a lot of research to find out that the Pi 1 through Pi 3+ aren’t particularly suited for NAS work. They may have the CPU horsepower, but with the on-board Ethernet and USB sharing the same USB2 port, their performance is reportedly not all that great.

The Pi 4, on the other hand, has entirely different hardware; the USB ports (of which there are two USB3 and two USB2) have their own controller, while the on-board Ethernet has its own controller. This makes for an ENORMOUS improvement in the performance of both USB:

and Ethernet:

With numbers like that, I thought it would be worthwhile to try building a little RAID1/mirrored home NAS around a Pi 4. Here’s what I used:

• Raspberry Pi 4, 2GB model, qty 1
• Official Raspberry Pi 4 power supply, qty 1
• 32GB Sandisk UHS-1 MicroSD card, qty 1
• 4TB Western Digital Blue 3.5″ hard drive, qty 2
• Vantec NexStar TX 3.5″ external USB3 enclosure, qty 2
• 5ft Category 5e patch cord, qty 1

I went with mirroring two disks (RAID1), so that is what I’m going to go through here. If you want to set up a single disk, or set up something like a four-disk mirror, or RAID5/6/1+0, you can use the same software I did but you’ll have to do a bit of research into the settings.

Oh, and if you are going to create a RAIDset with more than one disk, make sure they’re all the same size, otherwise the mirror will only be as large as the smallest of the disks that are part of the RAIDset!

I had originally planned to use openmediavault to mirror the disks and create the network shares, but unfortunately it doesn’t support USB-connected disks. That’s what I get for not reading enough before I buy stuff, I suppose. With omv out of the picture, I decided to try mirroring the disks and set up the network shares myself. Here’s how I did it:

Part 1: Set Up Your Raspberry Pi

I’m not going to get into this because there are already a ton of sites out there that will show you how to do this (and describe it better than I can). I built my NAS with the Raspbian Buster Lite image, dated 2020-02-13. Do not use wireless (don’t bother with a wpa-supplicant.conf file), but make sure you enable ssh, go through the raspi-config menu and don’t forget to apt update and upgrade!

Part 2: Assemble And Format The Disks

This part’s pretty easy. Install the hard drives in the enclosures, connect them to your PC, and using the software of your choice, remove any existing partitions on the disks and create a single NTFS partition (or ext4 if your PC is a Linux machine) that uses the entire capacity of the disk. Once that’s done and you get no errors, safely remove the enclosures from your PC.

Part 3: Put Together And Connect Your Hardware

This part’s pretty easy too. Connect the USB disks to the Pi and turn them on. If things are working properly, the physical enclosures and the disks will be present. To check if the Pi sees the enclosures, type lsusb:

To see if the actual spinning hard drives have been detected, type dmesg | grep sda for the first enumerated disk, and dmesg | grep sdb for the second:

Do not go any farther if the output of either of those commands doesn’t look correct, or if the disk capacity listed is different than you expect. Go back, check all of the parts and connections, and try again.

Part 4: Set A Static IP On eth0

You should at this point already have a cable connecting your Pi to your router or a switch. If you’re using wireless… well, I suppose you can do that if you really want or need to, but you’re going to be making your Pi do its work with one foot in a bucket. Use that RJ-45 jack and get yourself some nice clean Gigabit Ethernet goodness.

To set a static IP, use your favourite editor to edit the /etc/dhcpcd.conf file. Make sure to use sudo so you’re editing it as the superuser. Go right to the bottom of the file, and add the following lines:

# NAS Static IP for eth0
interface eth0
static routers=Z.Z.Z.Z
static domain_name_servers=A.A.A.A B.B.B.B

Where:

• X.X.X.X is the static IP address on your network that you want your NAS to be reachable at
• YY is the CIDR representation of your subnet mask (most home or small businesses will be /24)
• B.B.B.B is the IP address for your secondary DNS server (if you have one)

Make sure that you type everything exactly. Even if you only have one router and one DNS server, you still need to type static routers and static domain_name_servers with the “s”.

Once you’ve finished setting the dhcpcd.conf file, reboot your Pi. Once it comes back up, see if you can ping other devices both inside and outside your network. Then try to do another apt update and upgrade to see if your Pi can talk to the Raspbian repositories. If not, go back over the file and make sure the changes you made were saved. Also check to make sure everything is spelled correctly (remember it’s case sensitive).

Part 5: Mirror The Disks

Congratulations! If you’re here, that means you have successfully set up your Raspberry Pi, can see it on the network, and have two hard disks connected via USB. You are now ready to do something not a lot of other people do – use a Raspberry Pi to make a RAIDset out of a pair of USB-connected disks. Fortunately, the software (like the hardware) has made leaps and bounds since the last time I tried it and it’s pretty easy to set up.

First, let’s make sure the right stuff is installed:

sudo apt update
sudo apt install mdadm

Since you already made sure the disks were working in Step 2, you can go ahead and create a RAID1 mirror. In my case, I didn’t care about the partition size so I used the entirety of both disks with the following command:

sudo mdadm --create --verbose /dev/md0 --level=mirror --raid-devices=2 /dev/sda /dev/sdb

In this case, mdadm is being told:

-- create : Make a new RAIDset
-- verbose : Show what’s going on while the command is running
/dev/md0 : The name of the RAID device you’re creating
--level=mirror : Create a mirror (RAID1)
-- raid-devices=2 : How many disks will be used
/dev/sda /dev/sdb : The names of the disks that will be used

Again, this is how I set up my own little two-disk mirror. If you have a different number of disks or want to set up a different kind of RAIDset, the syntax is pretty much the same but the options are different. You may also want to use particular partitions instead of entire disks like I did. Check out the mdadm man page.

You should now see the lights on the enclosures blinking furiously and/or be able to feel/hear the the hard drives doing something. Depending on the kind and size of disks you have and the type of enclosure, creating the mirror and syncing it up may take up to a day. You can check the progress with the following command:

cat /proc/mdstat

which should give you output something like this, which shows you the status of the mirror sync:

Personalities : [raid1]
md0 : active raid1 sda[3] sdb[2]
3096885440 blocks super 1.2 512K chunks 1 near-copies [2/2] [UU]
[>....................] resync = 0.2% (61504/3096885440) finish=398min speed=14298K/sec
unused devices: <none>

Once it’s done, instead of the above, you should see something similar to the following when you run the same command:

pi@PI-0:~ $cat /proc/mdstat Personalities : [raid1] md0 : active raid1 sda[1] sdb[2] 3906885440 blocks super 1.2 [2/2] [UU] bitmap: 0/30 pages [0KB], 65536KB chunk Note the line with the [UU] at the end. Each U represents an active and healthy RAID disk. If you run cat /proc/mdstat and you see a _ (underscore) instead of a U, there’s a problem with a disk that requires your immediate attention. Now that the RAIDset is built, you need to save its configuration so your Pi knows what to do with it when it boots: sudo -imdadm --detail --scan >> /etc/mdadm/mdadm.conf exit Now confirm it was saved: cat /etc/mdadm/mdadm.conf and look for the line that says something like this (obviously your UUID will be different): ARRAY /dev/md/0 metadata=1.2 UUID=061a78a9:ceadf64b:b124c1d4:7e35ae85 name=PI-0:0 Now reboot your Pi, and once it comes back up, use cat/proc/mdstat and blkid to see if everything’s okay: Part 6: Create A Filesystem Now that the disks are mirrored, it’s time to put a filesystem on them. I use ext4, and I’m creating a filesystem on the RAIDset, NOT the physical disks, so the command is: sudo mke2fs -t ext4 /dev/md0 This may also take a little while. Once it’s done, edit the /etc/fstab file so that the filesystem on the RAIDset will automount at boot. I use the /mnt directory as the mount point, here’s what my fstab file looks like: Notice that the UUID of the partition is the same as the UUID for /dev/md0 in the output of blkid. Type the following to see if your fstab file is set up right: sudo mount -adf You should see something like this: In this case, /dev/md0 is mounted at /mnt and everything looks good. The use is at 12% because I’ve already been using the NAS – yours will probably say 0% or 1%. Now, shut your Pi down, then turn off the disks. Turn on the disks, wait for them to spin up, and boot up the Pi. Run those two commands again and make sure everything looks good before going any further. Part 7: Set Up A File Share With Samba Samba is a mature, stable, and very useful batch of software that makes it pretty easy to create simple network shares. It may already be installed, but just to be on the safe side: sudo apt install samba sudo apt install samba-common-bin Once it’s installed, you’re going to need to configure it by editing the /etc/samba/smb.conf file. I’m only going to set up one network share for now, and if you’re new to Samba, I suggest sticking to one share until you’re familiar with it. Before we edit the file, though, we need to create the directory that Samba will use to share over the network: sudo mkdir /mnt/NAS_FILEsudo chown pi /mnt/NAS_FILEsudo chgrp users /mnt/NAS_FILE Do NOT use /mnt as the directory for your file share – always use a directory that resides on the device you’re mounting. If for some reason /dev/md0 doesn’t mount properly, you may end up writing data to and filling up the SD card instead of using the disks! The default smb.conf file contains a number of examples, including one for a network share and one for a print share. Copy the default file: sudo cp /etc/samba/smb.conf /etc/samba/smb.conf_OLD Now, with sudo, use your favourite text editor to open /etc/samba/smb.conf and go to the bottom section of the file, labelled “Share Definitions”. Delete everything in that section and replace it with the following: [NAS] comment = NAS Fileshare path = /mnt/NAS_FILE browseable = yes read only = no writable = yes create mask = 0775 directory mask = 0775 valid users = pi So the “Share definitions” section in my smb.conf file looks like this: Notice how the “valid users” section has the name “pi” in it – you can change that to anyone you’d like (or have more than one user on that line), but for each user on that line, you’ll need to create an account on the Pi for them. I just stuck to the pi user because I wanted to keep things simple to start. To test your smb.conf file, run the following: testparm The “Loaded services file OK” is a good sign that your smb.conf file has no obvious errors in it. If you don’t get that message, go back through the file and make sure everything is spelled properly, etc. Now, for each user account you want to grant access, you need to run the smbpasswd utility to set them up in Samba. It will ask for a password, and that password really, really should really be different than the password that’s used by the user to log into the Pi itself! To add someone to the Samba system: sudo smbpasswd -a USERNAME To disable someone’s Samba account: sudo smbpasswd -d USERNAME To re-enable someone’s Samba account: sudo smbpasswd -e USERNAME In my case, I ran: sudo smbpasswd -a pi and gave it a password that was different from the password that I use for logging in with the pi user. At this point, Samba is installed, you’ve created a directory on the RAIDset that Samba will use for the file share, you’ve edited the smb.conf file, ran smbpasswd for every user that’s listed in the smb.conf file, and tested your configuration with testparm. It’s time to restart Samba so it loads the new configuration: sudo service smbd restart If you don’t get any messages or errors, things may actually be working! Part 8: Access Your New NAS Finally, the payoff – your own home-built NAS! How you will access it depends on the operating system on the computer you want to access it with. If you open your file or network browser, it may automatically show up. Otherwise, you will have to browse to it. Open your file or network browser and browse to the static IP address you set way back in Part 4. In Windows, it should look something like this: In Ubuntu, you may have to enter smb:// before the address: When you try to open the NAS share, you should be prompted for a username and password. The username will be: localhost\USERNAME, which in my case waslocalhost\pi …and the password will be whatever you set it to with smbpasswd. Some of my friends and family may disagree with this statement, but I like it when things are organized. To help with this, I designed and printed a lightweight frame that holds two disks and a Pi, and has several holes for 5mm M3 screws to fasten things like cable management or velcro or whatever to it. Here’s how mine turned out: I put the model on Thingiverse, it’s at https://www.thingiverse.com/thing:4235287 As for performance… this setup is much more responsive and can transfer files to and from the disks much faster than the old NAS. Disk fragmentation can slow things down, and the old NAS is a decade old, but it was only about half full so that shouldn’t have been too big a problem. Transfer rates to and from the Pi are faster than my home wireless is, and browsing the directories on the file share is no different than browsing the directories on my PC. Nice and quick. 150Mbps isn’t too shabby at all! The best I could get out of the old NAS was around 70Mbps. Bottom line – a Pi 4 with two external USB3-connected hard drives makes a serviceable and reasonably fast NAS for home or small business use, although there are security considerations that need to be addressed prior to using it out in the real world. So that’s the deal. I did a bunch of torture testing when I first set things up, and things recovered gracefully. I will do another post soon to discuss how to fix a mirror if there’s a disk failure or if you need to recover the array entirely due to a Pi failure. I hope you found this useful! ## Temperature And Humidity Display Using Arduino, DHT22, And MAX7219 Display I finished another project today. This time it’s a simple temperature and humidity display, and so far it’s working pretty well. It’s built around an Arduino Nano and uses a DHT22 sensor. The display is an extremely cheap MAX7219-based four-module LED matrix (130x32mm), and its brightness is controlled by a capacitive touch sensor (11x15mm). In this case, everything runs off a 5V supply so there are no level shifters needed and a single USB cable can power the whole thing. Any other 5V Arduino with hardware SPI will work fine here, too. The software libraries I used also support software SPI but I haven’t tried that out. Here’s the layout: • Everything is connected to the +5V and GND pins on the USB connector. • MAX7219 CLK to Arduino 13. • MAX7219 DATA to Arduino 11. • MAX7219 CS to Arduino 10. • DHT22 I/O to Arduino 2. • Touch sensor I/O to Arduino 4. I had everything on a breadboard but forgot to take a picture before wiring everything up to fit in the case… here it is wired up and just before being prepared to put into the case. The program uses the MD_MAX72XX and MD_PAROLA libraries for the display, and the SimpleDHT library for the DHT22. It took me a while to wrap my head around the MD_PAROLA stuff, but the examples included with the libraries were very helpful. Here’s the program: /* Temp and RH DHT22 MAX7219 for Dot 04 * Uses Nano to check DHT22 and display on 8x8 dot matrix (x4) MAX7219. * Meant to be used indoors. * Has two brightness settings, 4 and 15 (on scale of 0-15) * Runs off 5V USB. * MAX7219 controlled by MD_Parola and MD_MAX72xx libraries * DHT22 using SimpleDHT * PINS: * DHT22 data: D2 * MAX7219 clock: D13, data: D11, CS: D10 * Intensity: D4 * Uses a MAX7219 32x8 LED module from Banggood. Hardware type is MD_MAX72XX::ICSTATION_HW, 4 devices * Puts temp and RH on display at same time */ /* * MAKE SURE YOU RUN THE MD_MAX72XX_HW_Mapper to confirm the hardware setting for your particular display! * The results I got for the display I have were: * * HW_DIG_ROWS 1 * HW_REV_COLS 1 * HW_REV_ROWS 1 * Your hardware matches the setting for IC Station modules. Please set ICSTATION_HW. * */ #include <MD_Parola.h> #include <MD_MAX72xx.h> #include <SimpleDHT.h> #include <SPI.h> // Set up DHT22 vars for data TX/RX #define h_w 8 #define h_h 8 static unsigned char h_w_bits[] = { 0x3c, 0x42, 0xa5, 0x81, 0xa5, 0x99, 0x42, 0x3c }; #define s_w 8 #define s_h 8 static unsigned char s_w_bits[] = { 0x3c, 0x42, 0xa5, 0x81, 0x99, 0xa5, 0x42, 0x3c }; // Create instance for the DHT22 using pin 2 for data xfer SimpleDHT22 dht22(2); // Define the number of devices we have in the chain and the hardware interface // NOTE: These pin numbers will probably not work with your hardware and may // need to be adapted #define HARDWARE_TYPE MD_MAX72XX::ICSTATION_HW // Found using the MD HW mapping program #define MAX_DEVICES 4 // Four 8x8 modules on this particular board #define CLK_PIN 13 #define DATA_PIN 11 #define CS_PIN 10 #define BRIGHT_PIN 4 // Hardware SPI connection MD_Parola P = MD_Parola(HARDWARE_TYPE, CS_PIN, MAX_DEVICES); byte CountUp = 0; void setup() { delay(500); // Need this because display doesn't seem to start up right away. P.begin(2); // Using 2 zones, one for temp, one for humidity pinMode(BRIGHT_PIN, INPUT); P.setZone(0,0,1); P.setZone(1,2,3); P.displayZoneText(0, "Hi!", PA_CENTER, 75, 0, PA_PRINT, PA_NO_EFFECT); P.displayZoneText(1, "Hi!", PA_CENTER, 75, 0, PA_PRINT, PA_NO_EFFECT); P.setZoneEffect(0, 1, PA_FLIP_UD); // Need this because I glued the display in upside down >:-( P.setZoneEffect(1, 1, PA_FLIP_UD); // Need this because I glued the display in upside down >:-( P.setZoneEffect(0, 1, PA_FLIP_LR); // Need this because I glued the display in upside down >:-( P.setZoneEffect(1, 1, PA_FLIP_LR); // Need this because I glued the display in upside down >:-( P.displayAnimate(); delay(2000); } void loop() { jumpback: // If touch sensor is active, cycle through the 16 levels of brightness until sensor is inactive. int brightness_change = digitalRead(4); while (brightness_change == 1){ if (CountUp == 16){ CountUp = 0; } P.setIntensity(0, CountUp); P.setIntensity(1, CountUp); delay(250); CountUp = CountUp + 1; brightness_change = digitalRead(4); } float temperature = 0; float humidity = 0; int err = SimpleDHTErrSuccess; if ((err = dht22.read2(&temperature, &humidity, NULL)) != SimpleDHTErrSuccess) { // If we're here, there was a problem reading the DHT22. Show an error then try again. P.displayZoneText(0, "Dht", PA_CENTER, 75, 0, PA_PRINT, PA_NO_EFFECT); P.displayZoneText(1, "Err", PA_CENTER, 75, 0, PA_PRINT, PA_NO_EFFECT); P.displayAnimate(); delay(5000); goto jumpback; // I know, I know. Don't say it... } // Convert the float to a string to display char temp_result[6]; dtostrf(temperature,2,0,temp_result); // Convert the float to a string to display char hum_result[6]; dtostrf(humidity,2,0,hum_result); P.displayZoneText(1, hum_result, PA_CENTER, 75, 0, PA_PRINT, PA_NO_EFFECT); P.displayZoneText(0, temp_result, PA_CENTER, 75, 0, PA_PRINT, PA_NO_EFFECT); P.displayAnimate(); delay(3500); // DHT22 max sample rate is about 2 seconds. } If you are using a MAX7219-based display, save yourself some time and frustration by connecting it and running the MD_MAX72XX_HW_Mapper program that comes with the MD_MAX72XX library before you do anything else. It will tell you how your display is set up, regardless of how it actually looks. After doing some testing, I found that the capacitive touch sensor I was using could reliably detect my finger out to about 5mm away. That was great because then I could hide it inside the case and there’d be no switch, no pad… just a “magic” spot on the back that changes the brightness if you put your finger there. I designed a case for this particular project, including the specific display and touch sensor I had on hand. It’s vented, has a hole for a USB cable, and is closed up with four 6mm M3 screws: With everything wired up and tested, I hot-glued everything… and I mean everything. Every connector, every module (except the Nano’s mini-USB port – never know if I’ll want or need to reprogram it) … it’s all quite secure inside the case. I glued put a piece of plastic on the back of the display just in case any other parts work their way loose and came in contact with it. I’m still a little wary of doing things this way, but it sure beats drawing up and etching boards for this kind of stuff! Once the glue had cooled and I confirmed everything was stuck good and tight, I closed up the case and plugged the cable into a 5V USB power supply. The LEDs flashed, and then… everything was upside down. I’d glued the display in upside down. So… another 45 minutes or so of pondering and looking and I found how to flip the display in software so it looked right again. If you run into this problem, check out setZoneEffect() in the MD_PAROLA documentation. Here it is, from the back: And from the front, display pointing the right way: The STL files for the case are available at https://www.thingiverse.com/thing:4202464 ## Find A File That Contains A Particular Text String (Windows) Windows File Explorer is many things. One thing it is not, however, is good at searching. It used to be… but somewhere along the way something got broken. Fortunately, there’s a command-line tool that works much better than the GUI, called findstr. You can look up the options by typing findstr /? If you’re looking for a particular text string and you only want to know which files contain that string, use the following command: findstr /S /I /M /C:TEXT_STRING_HERE * The /S means search this directory and all subdirectories. The /I means don’t be case-sensitive. The /M means print only the filename if there’s a match. The /C: specifies the text string you’re looking for. The * means check everything. ## Fix For Arduino IDE Compiling Very Slowly In Windows My Raspberry Pi has been compiling Arduino programs in about a tenth the time that my main Windows machine has. The Windows machine is not a slouch – i7-7700HQ with 16GB RAM and a SSD, and it was getting annoying waiting for several minutes while some of the larger ESP programs compiled. Turns out the antivirus was running full-tilt, scanning every file as it was loaded into the compiler, pinning the CPU. The fix for me was to set an exception in my AV software for the C:\Users\[yourname]\AppData\Local\Arduino15 folder. It made a huge difference in speed and my laptop no longer sounds like a jet engine when it’s compiling a 20-line program for a microcontroller with 2.5kB of RAM… ## ESP32-CAM Low Power Trail Camera I’ve been spending a lot of time lately working with the ESP32-CAM module. It doesn’t produce the best pictures I’ve seen, but for the cost (I’ve found them for$9, including the OV2640 camera!) and the number of features and horsepower, they’re tough to beat.

One of the things I want to do with them is put a couple outside and get pictures of the different kinds of animals that wander through the yard and leave footprints in the snow. When I mentioned this to a buddy of mine, he immediately wanted to know if they could be used to watch for motion and take pictures in case someone was trying to break into his shed or cabin. Sure, I told him – I didn’t see any reason why not. His response was to immediately ask me how many I could make for him and how quickly I could do it.

Unfortunately, it was just an idea at the time and I hadn’t actually tried to do it. I figured it wouldn’t be too tough – after all, the ESP32-CAM AI-Thinker modules I use have several GPIO pins broken out. I was wrong.

Turns out some of the GPIO pins are used by the camera, and the rest are used by the uSD card slot that’s on the board. One of them (D4) seems to be used by BOTH the camera (camera flash) and the uSD card slot (data line).

I tried a bunch of things and didn’t have much luck, and when I looked around for information, there were lots of links but I couldn’t find any information that quite fit what I was doing.

Finally, I found a link to some ESP documentation, which got me started. Looking into the various ESP libraries for the SD card, using a FAT32 filesystem, the camera, and the on-board EEPROM took a while but after I figured one or two of them out, the others were easier.

After going through my various parts bins, I cobbled together a circuit that seems to reliably work. Here’s the schematic of the whole thing:

+V on the schematic is the power supply you want to use. Power for the ESP32 first goes to an AMS1117-3.3 regulator. According to the AMS1117 datasheet, it will run to where the input is only 1V higher than the output. The output is 3.3V, so it should be able to run down to 4.3V. The absolute maximum input voltage is 15V, so powering it from 4xAA/4xC/4xD alkaline batteries (6V) is fine. Even 9 or 12V should be OK, but check the regulator on your board first to make sure.

Remember that if you want to power it from rechargeable NiCd or NiMH batteries, those are 1.2V, not 1.5V, so you’d probably want to use five of them, instead of four alkalines. Same with those long-life lithium batteries – they’re 1.2V too.

The block labelled “OPTIONAL” is there if you want a switch that will keep the MOSFET (and ESP) turned on while programming. You can also just move the ESP GND pin from the MOSFET drain to ground while programming. Or… if your PIR will remain on while motion is present, you can just wave your hand above the sensor until programming is done. That’s what I do.

R1 and R2 are necessary, particularly if you have a MOSFET with a high input capacitance. They keep the MOSFET gate from momentarily pulling a large amount of current which could damage the PIR or ESP.

Why the 4N37? Because the ESP is not connected to the ground rail when the MOSFET is turned off, so GPIO13 does a very noisy “high-ish” float which leads to unpredictable results. Note that the 4N37 diode side circuit goes from GPIO13 to the anode, the cathode goes to R3, and R3 goes back to the GND pin on the ESP – NOT the ground rail from the power supply!

This circuit works best with low-Vf Schottky diodes that can tolerate a reverse voltage at least 2x the highest possible voltage in your circuit. Tested and works with BAT41 and 11DQ06. Tested and works with old-school 1N34 germanium diodes (but I probably wouldn’t use them for real-world applications). It seems to mostly work but not as reliably with typical 1N914 and 1N4001 diodes. It does NOT work with anything with a Vf larger than about a volt, like LEDs.

This circuit also works best with MOSFETs that are fully on at a low voltage, like 2.5 to 4.5V, and have a very low drain-source resistance when on (tens to a couple hundred milliohms). Tested and works with IRLI640G and DMN1019USN-7.

Normally I’d put bypass capacitors across the 5V and GND pins of the ESP, but here’s the ESP32-CAM power circuit:

Note the abundance of capacitors, which is pretty great. A 0.1uF capacitor probably wouldn’t hurt, but I don’t think it’s necessary unless you’re using a very noisy power supply.

So that’s the schematic. Breadboarded up, this is how it looks:

Here’s how it works:

• When power is applied to the circuit, the gate of the MOSFET is low and doesn’t conduct, so the ESP is disconnected from the ground rail. The circuit pulls about 16uA at this time.
• When the PIR sensor detects motion, its trigger pin goes high for two seconds. This signal is sent through a diode and 47k resistor to the gate of the MOSFET, which turns it on.
• With the MOSFET turned on, the ESP now has power and boots. As soon as it can, it sets GPIO13 high. This turns on the input of a 4N37 optoisolator, which turns on its output transistor. The output transistor is also connected to the gate of the MOSFET through a diode and a 47k resistor. This keeps the MOSFET turned on even after the PIR trigger line goes low.
• The ESP goes through the paces of checking for and mounting the uSD card, starting up the camera, and checking the EEPROM and reading the number from it that indicates the last picture that was taken (PIC_COUNT) prior to the previous shutdown.
• If there is a problem at any point in the startup, the ESP will set GPIO13 low, which will turn it off and wait for the next trigger to boot again. I know it’s 2020, but sometimes a reboot still fixes things.
• If there are no problems, it gets to the main loop, which takes the number of pictures specified by a while loop that increments the variable COUNTUP (in the program here it takes five pictures). Each time through, the picture counter (PIC_COUNT) is increased by 1. The circuit pulls about 130-140mA at this time.
• Once COUNTUP reaches the maximum set in the while loop, the ESP saves the current value of PIC_COUNT to the EEPROM and then sets GPIO13 low. This should turn off the MOSFET and remove power from the ESP.
• If there is still power, the ESP waits for 500ms after it tried to shut itself down. If it’s still awake, then that means the PIR has either re-triggered or is still triggered so it’s a good idea to get more pictures. The ESP sets GPIO13 high again and loops back to take another five pictures.

Here’s what it looks like when it’s running. Note the camera flash LED on the board glowing faintly instead of blazing like a million suns like it usually does. When the LED is on, the ESP is communicating with (and hopefully writing an image to) the uSD card.

You may be wondering why it works, though. After all, there don’t seem to be any usable free GPIOs when using both the camera and the uSD card, so what’s with GPIO13? Well, it comes down to changing this line:

SD_MMC.begin("/sdcard")

to this:

SD_MMC.begin("/sdcard",true)

Selecting “true” tells the ESP to talk to the uSD card in 1-bit mode instead of the usual 4-bit mode. This frees up a couple of GPIO pins, one of which is GPIO13. The disadvantage to using 1-bit mode is that it’s slower, but I’m pretty sure the ESP itself is going to be the bottleneck here. Plus, the OV2640 and lens aren’t super-high quality so setting the JPEG image quality high and making huge files isn’t necessary (or useful).

Here’s the program in its entirety (it looks kind of mangled but if you copy and paste it into a text document or the Arduino IDE it comes out properly):

/* ESP32-CAM Low Power Trail Camera v1
* Mark's Bench (http://marksbench.com)
* Uses ESP32-Cam AI-Thinker with OV2640 camera to take pictures and save to SD card when triggered by PIR
* ESP32 is connected to power rail via MOSFET. MOSFET is initially turned on by PIR trigger and kept on by setting pin D13
* on the ESP32 high as soon as ESP starts up.
*
* ESP then takes 5 pictures and saves them to the SD card, after which it sets D13 low, which turns the MOSFET off,
* cutting the ESP off from the GND rail.
*
* If the PIR trigger remains high or goes high again during when the ESP32 would shut down, then take another five
* pictures and try shutting down again.
*
* Advantage to this scheme is a power savings - power draw is less than 20uA when the MOSFET
* is off and the ESP32 is shut down. Power draw is around 130-140mA when pictures are being taken and saved.
*
* Disadvantage is that when using both the camera and the SD card, there are no easily usable GPIO pins available.
* To get around this, use 1-bit SD card access instead of the usual 4-bit.
* It slows things down but you can still get an image with ok quality about once a second
* at full resolution (1600x1200) on the OV2640.
*
*
* Information on and code examples for using the ESP32-CAM library:
* https://github.com/yoursunny/esp32cam
* https://github.com/espressif/esp32-camera
* https://github.com/espressif/arduino-esp32/tree/master/libraries/ESP32/examples/Camera/CameraWebServer
*
* Information on and code examples for using the ESP32 SD_MMC library:
* https://github.com/espressif/arduino-esp32/tree/master/libraries/SD_MMC
*
* Information on using the ESP32 EEPROM (the Preferences library):
* https://github.com/espressif/arduino-esp32/tree/master/libraries/Preferences
*
* VERY useful ESP32 documentation:
* In particular, the "ESP32-WROOM-32 Datasheet", "ESP32 Datasheet", and "ESP32 Hardware Design Guidelines".
* Also, the schematic at:
* https://github.com/SeeedDocument/forum_doc/raw/master/reg/ESP32_CAM_V1.6.pdf
* And the specification page (which has some errors) at:
* https://github.com/raphaelbs/esp32-cam-ai-thinker/blob/master/assets/ESP32-CAM_Product_Specification.pdf
*
*
* ***TO PROGRAM: Set Board to "AI Thinker ESP32-CAM"***
*/

#include <esp_camera.h>
#include <FS.h>
#include <SPI.h>
#include <SD_MMC.h>
#include <Preferences.h>

// The ESP32 EEPROM library is deprecated. Use the Preferences library instead.
Preferences preferences;

// The following defines are for the ESP32-Cam AI-THINKER module only. I haven't tried any others.
#define CAM_PIN_PWDN    32
#define CAM_PIN_RESET   -1
#define CAM_PIN_XCLK    0
#define CAM_PIN_SIOD    26
#define CAM_PIN_SIOC    27
#define CAM_PIN_D7      35
#define CAM_PIN_D6      34
#define CAM_PIN_D5      39
#define CAM_PIN_D4      36
#define CAM_PIN_D3      21
#define CAM_PIN_D2      19
#define CAM_PIN_D1      18
#define CAM_PIN_D0       5
#define CAM_PIN_VSYNC   25
#define CAM_PIN_HREF    23
#define CAM_PIN_PCLK    22

// Create a variable to hold the picture number. Since the SD card is formatted FAT32, the maximum number of files
// there can be is 65534, so a 16-bit unsigned number will be fine.
uint16_t PIC_COUNT = 0;

void setup(){
pinMode(13, OUTPUT);    // GPIO13 available when using SD_MMC.begin("/sdcard",true) for 1-bit mode (set below)
digitalWrite(13, HIGH); // Hold the gate of the MOSFET high as soon as possible after boot to keep the power on
// after the PIR is done triggering.

//Serial.begin(115200); // Uncomment for troubleshooting

preferences.begin("trailcam", false); // Open nonvolatile storage (EEPROM) on the ESP in RW mode
PIC_COUNT = preferences.getUShort("PIC_COUNT", 0);  // Get the stored picture count from the EEPROM.
// Return 0 if it doesn't exist.
// getUShort() fetches a 16-bit unsigned value

// Now, configure the camera with the pins defined above and recommended settings for xclk, led_c, and format.
camera_config_t config;
config.pin_d0 = CAM_PIN_D0;
config.pin_d1 = CAM_PIN_D1;
config.pin_d2 = CAM_PIN_D2;
config.pin_d3 = CAM_PIN_D3;
config.pin_d4 = CAM_PIN_D4;
config.pin_d5 = CAM_PIN_D5;
config.pin_d6 = CAM_PIN_D6;
config.pin_d7 = CAM_PIN_D7;
config.pin_xclk = CAM_PIN_XCLK;
config.pin_pclk = CAM_PIN_PCLK;
config.pin_vsync = CAM_PIN_VSYNC;
config.pin_href = CAM_PIN_HREF;
config.pin_sscb_sda = CAM_PIN_SIOD;
config.pin_sscb_scl = CAM_PIN_SIOC;
config.pin_pwdn = CAM_PIN_PWDN;
config.pin_reset = CAM_PIN_RESET;
config.xclk_freq_hz = 20000000;
config.ledc_timer = LEDC_TIMER_0;
config.ledc_channel = LEDC_CHANNEL_0;
config.pixel_format = PIXFORMAT_JPEG;

// Make sure there is PSRAM available (the AI-Thinker module has PSRAM). Otherwise, don't go any further.
if(psramFound()){
config.frame_size = FRAMESIZE_SXGA; // If there's PSRAM then there's enough memory to capture up to 1600x1200
// The following resolutions are available:
// 96x96 (96x96)
// QQVGA (160x120)
// QQVGA2 (128x160)
// QCIF (176x144)
// HQVGA (240x176)
// 240x240 (240x240)
// QVGA (320x240)
// CIF (400x296)
// VGA (640x480)
// SVGA (800x600)
// XGA (1024x768)
// SXGA (1280x1024)
// UXGA (1600x1200) **Full-resolution for OV2640

config.jpeg_quality = 10; // Valid: 0-63, with 0 being highest quality and largest file size.
// Anything lower than 8 creates large file sizes that take a long time
// to save to the SD card.
// The camera and lens aren't the best quality, so huge files
// won't get you a better picture beyond a certain point.
config.fb_count = 2;  // With the PSRAM, there's enough memory for two framebuffers, which speeds captures.
}
else{
while(true){
// The AI-Thinker module has PSRAM. I haven't tried any module without PSRAM.
//Serial.println("NO PSRAM FOUND"); // Uncomment for troubleshooting
delay(500);
}
}

// Start up the camera with the configuration settings made earlier in the "config." statements.
esp_err_t err = esp_camera_init(&config);
if (err != ESP_OK){
// If we're here, there's a problem communicating with the camera.
// Turn the ESP off and wait for the next trigger.
digitalWrite(13, LOW);
//Serial.println("CAM FAIL"); // Uncomment for troubleshooting
while (true){
// Need this loop to wait in case the PIR is keeping the power on.
}
}

// Start up the SD card, using 1-bit xfers instead of 4-bit (set the "true" option). Frees up GPIO13.
if(!SD_MMC.begin("/sdcard",true)){
// If we're here, there's a problem with the SD card.
// Turn the ESP off and wait for the next trigger.
digitalWrite(13, LOW);
//Serial.println("SD FAIL 1");  // Uncomment for troubleshooting
while (true){
// Need this loop to wait in case the PIR is keeping the power on.
}
}

// Query the card to make sure it's OK
uint8_t SD_CARD = SD_MMC.cardType();
if(SD_CARD == CARD_NONE){
// If we're here, there's a problem with the SD card.
// Turn the ESP off and wait for the next trigger.
digitalWrite(13, LOW);
Serial.println("SD FAIL 2");  // Uncomment for troubleshooting
while(true){
// Need this loop to wait in case the PIR is keeping the power on.
}
}
}

// We are now done the setup and should be ready to take pictures in the main loop() function.

void loop(){
uint8_t COUNTUP = 0;  // Create variable to take multiple pictures.
while (COUNTUP <=4){  // Take 5 pictures before shutting down.

// Take picture and read the frame buffer
camera_fb_t * fb = esp_camera_fb_get();

if (!fb){
// If we're here, there's something wrong with the data in the frame buffer.
// Turn the ESP off and wait for the next trigger.
digitalWrite(13, LOW);
while(true){
// Need this loop to wait in case the PIR is keeping the power on.
}
}

// If we're here, the image was captured. Begin the process to save it to the SD card.
// First, create the file name and path. Currently set to make files like /pic123.jpg
String path = "/pic" + String(PIC_COUNT) + ".jpg";

fs::FS &fs = SD_MMC;

// Now, create a new file using the path and name set above.
File file = fs.open(path.c_str(), FILE_WRITE);
if(!file){
// If we're here, there's a problem creating a new file on the SD card.
// Turn off the ESP and wait for the next trigger.
digitalWrite(13, LOW);
while(true){
// Need this loop to wait in case the PIR is keeping the power on.
}
}
else
{
// If we're here, the file was created. Now write the captured image to the file.
file.write(fb->buf, fb->len);
PIC_COUNT = PIC_COUNT + 1;  // Increment the picture count number each time there's a successful write.
if(PIC_COUNT >=65500){
PIC_COUNT = 0;  // FAT32 has a limit of 65534 files in a folder
}
}
file.close(); // Done writing the file so close it.

// Free the memory used by the framebuffer so it's available for another picture
esp_camera_fb_return(fb);

COUNTUP = COUNTUP + 1;  // We are done an image capture cycle. Increment the count.
}

// If we're here then we've taken the pictures and we are ready to shut down. Write the current file number to
// the EEPROM, then set D13 low.
preferences.putUShort("PIC_COUNT", PIC_COUNT);  // Store the picture count number in the EEPROM
// Normally you'd want to do a preferences.end() to properly close the EEPROM but since the intent is to
// shut the ESP down, it's not needed, and not having to open and close it every capture cycle speeds things
// up and saves some wear on the EEPROM.

//Serial.println("Shutting down."); // Uncomment for troubleshooting
digitalWrite(13, LOW);
delay(500);

// The ESP should be shut down at this point. If the PIR is still triggered or has re-triggered and is keeping
// the MOSFET on, then set D13 high and allow the program to loop again to take another five pictures.
digitalWrite(13, HIGH);
//Serial.println("Looping back.");  // Uncomment for troubleshooting

}

Hopefully there are enough comments to make heads or tails of it. A few notes:

• This is for the AI-Thinker module with the OV2640 camera only. It’s the only one I’ve tried. It will probably work with other models of ESP32-CAM, but you will need to check the #define for each pin, see how much of what kinds of storage are available, and what settings the camera you’re using requires.
• The ESP32 Arduino-compatible “EEPROM” library is deprecated; the new way to do things is with the “Preferences” library.
• Before programming, set the board type to “AI Thinker ESP32-CAM”. Again, this is for the AI-Thinker module only.

If you’re looking for documentation on the ESP32-CAM or the libraries I used to get this working, it’s all in the following links. For the libraries, be sure to check out the examples and .h files for options and how various things work:

I haven’t put it outside yet, but as a test of the ESP and circuit, I changed the program so the ESP would take and save as many 1600×1200 JPEGs at compression level 9 as quickly as possible. The circuit was powered by four grocery-store branded AA alkaline batteries that were unused but of unknown age. It ran for 16 hours 21 minutes and took 23475 pictures before the batteries died. Not bad!

I know there is a lot of room for improvement – both in the circuit and in the program. When building this, I was limited to what I had on hand – a P-channel MOSFET might be a better choice, and I’m sure there’s a better way to do things than with the 4N37. For now, though, I’m pretty happy that it works reliably. Now I need to put it in a box and get some pictures of those critters in the yard.

If you made it this far, congratulations! If you build this or have a better way to do this, I’d be curious how it turned out! Feel free to drop a comment here or send me a message using the contact form!