Solar charging ESP-Now BATMAN prototype 6

Prototype 5 sucked, trying to bodge in the ESP32-S2 breakout to the old board just didn't work well, so I did another prototype. Also as I now have the Nordic Semiconductor Power Profiler II, testing and measuring power use is so much easier and I could ditch the INA219 current sensors. These added a lot of mess to the previous prototypes.

As it's easy to adjust the voltage from the PPK2 it almost stands in as a dummy solar panel, although you can't current limit the output.

This latest prototype mostly came about because I designed a new schematic in EasyEDA, had a crisis of confidence about pin choice and how well it would work and resolved to just build it. Also it's Chinese New Year and I'm not in a hurry to order the boards.

I'm now absolutely set on using the ESP32-S2 for this project but I'll run this prototype off the panels for a few days and see how it behaves.

Update: I can't continue using the PAM2301 buck regulator I had intended to, testing showed it 'trips out' when panel voltage is ~6v. Which is fair enough given that's what's in the data sheet, but my expectation was charging load would keep voltage on a 5.5v panel below that, even though no-load voltage can be quite high. This is not true.

Creating a UI on a microcontroller: Part 11

I've been doing lots of work on the flow of things in the user interface in the terminal application so it works better. The deeper in I get the more boilerplate I'm writing to make buttons appear and disappear without leaving stuff floating around, so it's quite slow progress.

On the plus side, the syncing of user accounts and so on is working nicely and I've now made it so that it live updates. Make a change to a user and it appears near-instantly on the other terminals. Previously it synced the files on the SD card but they didn't show until a reboot.

Actually coding that to happen took another swathe of boilerplate but each time I do a thing like this I'm edging closer to a believable looking application. Also a bit of bugfixing which might have finally nailed the occasional exceptions when using a mouse.

As it's getting closer to something I can demonstrate I did a quick show and tell on Brian Lough's 'Project Doc' stream this evening. Which I believe is recorded for posterity.

Creating a UI on a microcontroller: Part 10

I've done a little more work on my retro 'computer terminal' application. When it started out, the key feature was messaging over the mesh network library I've also been working on.

All the code was there but just commented out while I got the user interface library knocked into shape. So I uncommented it and spent some time making some improvements. Again it also showed up some limitations in the UI library. Most of these were around showing/hiding the cursor and moving it back to the line where you're typing reliably.

With these ironed out, the basic chat functionality pretty much just worked despite being written a year ago and not touched since.

I've done a little video of two terminals sending chat messages. At one point I had a 'bot' that produced Lorem Ipsum any time there was activity in a chat. I must dust that off.