Ah! I’m late! Totally forgot to write this on Friday, then yesterday had a few things crop up and didn’t have the time.
Anyway, what have I learned in the past week? Well, for one, of the four ESP8266 modules that I had bricked, none of them actually were. As it turned out, I had the wires to the screen in such a way that they were causing it to not start properly. Changing the wires (And the PCB itself) fixed that issue, so now I have four working ESP8266 prototypes!
This DID lead to an important lesson: The ADC on the ESP8266 only reads in on 0-1v, give or take. The boards I had used had built-in voltage dividers which I had missed. Thankfully, I spotted this after the Feather Huzzah I got ended up with weird readings. So, now the V3 has the appropriate voltage dividers. While I was thinking about resistors, I went and double checked – Turns out, I had also missed the I2C pullup resistors, so those have been added in as well
I also posted the preliminary files for the V3 onto GitHub. They’re a bit sparse, since they’re not finished, but if you want to toss code at me or point out circuit board flaws, I’m perfectly fine with that. In fact, MintShard on Discord pointed out a potential issue with the battery ADC – As it’s continually monitoring the battery voltage, the ADC pin will be out of spec with a much higher voltage than it should have when the device is off. To test this, I finally got around to purchasing a benchtop power supply along with some breakout boards and ADCs to test. I’ll figure out the breaking point for these things, and see if I have to modify the design of the circuit board to compensate.
I’ve also started the order for the first prototype circuit boards. Those should be here early next week, and at that point I’ll be able to put together and test the V3 design. If all goes well, it’ll work. But as the V2 and V1 have shown, all rarely goes well the first time.
On Saturday I’ll be putting up the results of the ADC testing, along with whatever else I manage to do this week. I’ll be honest, while there is still stuff I can do with the programming, a lot depends on the circuit board, so I’ve been playing a bit of Mass Effect: Andromeda lately.