Use Pi3 to power electronics from a Greeting Card

January 17, 2024, 22:03

stettin.palver

I have the guts from a greeting card that was originally powered by two CR2032 cells. After some investigation it appears each cell powers the speaker and motor separately, so they only need 3v each. I tested this by removing both cells, then activating each feature one by one. I'm curious if I can use the 3.3v on the Pi3 to power one or both of those features through python. I'd be adding a button for control to turn it off and on. Realistically I think it would be easier to desolder the motor leads and wire to the Pi directly, but the music portion has a chip to play a specific tune, as well as an external speaker. If it is indeed possible to power this from the Pi, how should I connect it up? 2 white wires go to the speaker Red/Black to got the motor The switch is in the corner and is constantly on unless a piece of paper (tab from the card) breaks the connection.

k9t33n

1. never and I mean absolutely never solder directly to the pi! I have seen far too many people lose their pis this way 2. you need to check the amperage the devices require

stettin.palver

I would never do that. I was talking about removing the motor and connect through a breadboard or something. As for amperage, no idea how I would look that up. Greeting cards don't come with documentation. I looked up 7-1025WW and didn't find anything.

oops.se

I recommend that you connect a multimeter and measure the current. The motor could need a protection circuit as it is a inductive load and that can cause a back EMC that can harm the GPIO/Pi