VanceVagell
commented
1 month ago Thanks for the ideas, puterboy! I'd welcome any PCB design contributions, as I'm very new at that and it took a lot of experimentation and learning to reach the point the project is at.
That said, I did have several earlier prototypes, which used different ESP32 modules. The smallest was Adafruit QT Py ESP32-S2, which is really rather tiny. I did get it to work, but it wasn't up to par with what I wanted the project to do -- in particular it does not have a hardware UART and the software one failed unpredictably. Also, the audio was limited to 8kHz because the processor was just too slow, and single-core. I also built an earlier version around the DORHEA ESP32 D1 Mini NodeMCU, which is a bit more compact but it doesn't have pin headers for easy soldering so it's harder for people to work with.
In terms of #3, one major goal is to keep the kv4p HT battery-less, since a major benefit is just throwing it in a bag or glove compartment or whatever and knowing that as long as your phone is charged you can use it (don't have some other battery you need to keep topped-off). That's why I didn't go with something like a Bluetooth link to the phone (also, there are other radios that have this). But again, if you're interested in contributing a variant that has those features, I'd love to include it!
One thing related to #3 I do really want to offer, is to update the Android app to allow you to pair your phone to a laptop, and use the kv4p HT as a modem so you can do whatever arbitrary amateur radio data experiments you want, like SSTV etc. I actually think this would be fairly easy.
Thanks for the ideas!
puterboy
wolrah
esev
thekalinga
seanauff
Jonty
DrFrankReade
SmittyHalibut
m1geo
Magnum164
For smaller size, you might want to consider the ESP32-Devkit module which has only 30 pins vs. 38 pins on the ESP32-WROOM. I thinks it's also a little cheaper. This should require only a trivial change to the PCB since presumably you are only using a small subset of the GPIOs anyway.
Even better, how about designing a board that avoids the module and just uses the ESP32-S3 chip plus the CP2102 USB chip plus/minus a couple of other passive components to make an even smaller device. The assembly would be a little harder and you might not even save on cost, but you would have a more compact/integrated board.
Finally, how about adding an option to the firmware to use wireless connectivity between the phone and the ESP32 using the ESP32 in AP-mode. Then you wouldn't need to use a USB connector and could place the PCB board anywhere. This could be especially useful if you want to use a larger fixed antenna.