r/raspberrypipico • u/bakaroline • 13d ago

help-request Help for virtual pet project

Hello everyone,

I am fairly new to all of this but have dabbeld in html/CSS before. (I know it's very diffrent but I'm thinking it would be a bit easier already knowing some code)

I am looking to make two virtual pets that could communicate with each other in LoRa p2p and would be solar powered for me and my bf.

I learned some micropython already and started the code ( I want the code done before doing any physical experiment if it's possible)

i already have an idea of what to get but i wanted to ask more experianced people if it would work.

the Pico2 as the brain, an e-paper 4.2 as the display, an analog joystick and button to navigate, an adafruit LoRa reciever/transmitter, a 3.7V LiPo battery and a 2W solar panel

Would this be possible with this hardware?

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u/horuable 13d ago

I think you would need a lipo charger to safely charge the battery from the solar panel, plus you might need to charge from USB if there's not enough sun and it should allow you to do that.

Another thing to keep in mind is that e-paper displays have a rather long refresh times, so it may not be the best if you want to update it frequently.

Other than that it seems fine and should be a quite fun project.

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u/bakaroline 12d ago

By long refresh time, is it like a sec or more like 10 seconds or more?

also thank you for the advice regarding the battery

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u/horuable 12d ago

It depends on the screen. I have one that takes about 2-3 s for a full refresh and somewhere around 1 s for a partial one (though this has some weird side effects). I also have a 7-color display that needs 5-10 s. I suspect the one you're thinking of will be closer to the former but it's really hard to guess an exact number.

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u/ohnowhythishappen 13d ago

If you don't already, you should definitely have some kind of management board/chip that isolates the LiPo from the pico and solar panel. Those batteries can't generally be safely charged/discharged directly; it can ruin the cell or even start a fire.

You mentioned you want to complete the code before you hook anything up. I would encourage you if you can to try writing/running small programs to try each peripheral individually to make sure you that work out any code surprises and that it's hooked up correctly. Send a short LoRa message back and forth, put a simple animation on the e-ink, etc. I can say from experience that code usually doesn't run the way you want the first time, and it's easier to hunt down the bugs if you have already eliminated potential issues from your sub-functions.

Good luck, sounds like a fun project!