So… here we are. It’s been a little over a week since I started this project. Lots of ups, downs, laughs, tears, fist-shaking, face-palming, thumbs-upping, head hung in defeat, and arms raised in victory. I gave up on the Raspberry Pi Zero/Arduino combination (curse you, Timer3!!!) and switched to a Raspberry Pi Pico microcontroller (which, aside from making an LED blink by copy-pasting an example a few months ago, I knew nothing about) and started the electronics from scratch. By yesterday evening, things were moving along again. And in the end…

I failed.

It was pretty close, though. By this morning, my little robot could move around on its own and successfully detect and turn to avoid (some) obstacles using an HC-SR04 ultrasonic rangefinder. I was working on LED rangefinding and cliff sensing when I ran out of time.

Head bowed and properly ashamed, I told my wife that my robot sweeper wasn’t ready. She assured me that it was “cute” and thanked me for not setting the house on fire. Then, a twist: she’s been doing a ton of research into the little robots and based on the layout of our house and the stuff we have kicking around, she’s not sure which one would be a good fit. We even talked about getting a (gasp) cordless stick vacuum instead. Personally, I’d still rather have a robot because neither of us enjoy vacuuming or sweeping (does anyone?) and it’s more likely to get done if a computer does it.

Regardless, the sale is now over and we didn’t buy anything. Which means… I have more time. It’s not really a challenge anymore since we don’t know when the next good sale will be (or even what we want) but as it’s been quite the learning experience and we both agree that having a cheap little sweeper robot can’t hurt, I’m going to keep working on this project.

I have also “discovered” the Pi Pico. I’ve had a couple of them for a while now but since most of the stuff I do is with an Arduino, they’d been sitting around until I had time to tinker with them. Well, in the last 48 hours or so I’ve tinkered with them until my eyes would no longer focus and I’ve got to say that I’m quite pretty extremely impressed. Setting up MicroPython was easy, it’s easy to program with Python, and it has so many peripherals built in (not to mention the PIO stuff which I haven’t tried but looks great) that it’s… well… pretty amazing. And I’ve barely scratched the surface. I’ve got a million other project ideas for it, and it could well become my go-to when I need a microcontroller for something.

With the time constraint relaxed (at least for now), I’m very interested in seeing where this project goes. But now it’s late again and I really, REALLY need to clean my piles of components, wires, and papers off the dining room table before I go to bed.


  1. You say that it was hard to find the “right” gadget in the store. How about finding a hackable one and making it right, rather than starting from scratch. I think there are forums for hacking roombas, and at least initially iRobot pretty much facilitated it.

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