In general, this is certainly possible, and probably not even hard.
If you're trying to reuse a switch already installed in the car, well, that could be complicated. You might be able to read the switch over the car's CAN bus, but good luck finding documentation. Easiest thing to do is to wire the Pico in parallel with the switch, allowing you to read the switch parasitically. Although the car's internal low-voltage bus will be a nominal 12 V, the actual electronics will operate on ≤ 5 V. Check with a voltage meter; with any car manufactured this millennium, there's a decent chance it's already 3.3 or 2.5 V logic levels, which would be directly compatible with a Pico.
To drive a relay from a Pico, you'd use probably want to use something like a TIP120 Darlington transistor. In this case, the same circuit used for a 5 V Arduino will work generally work on a Pico, so I'd suggest using "Arduino" instead of "Pico" in a search. An important thing to note is that when a relay opens or closes, the magnet inside will generate a brief voltage pulse that will eventually damage your Pico. This is why most circuits you find online include an extra seemingly-useless diode; the diode shorts out the voltage pulse, protecting your microcontroller.
Converting 12 V to 5 V is easy. Get literally any random USB charger. Get a generic buck converter module. Use a LM358.
If you're trying to reuse a switch already installed in the car, well, that could be complicated. You might be able to read the switch over the car's CAN bus, but good luck finding documentation. Easiest thing to do is to wire the Pico in parallel with the switch, allowing you to read the switch parasitically. Although the car's internal low-voltage bus will be a nominal 12 V, the actual electronics will operate on ≤ 5 V. Check with a voltage meter; with any car manufactured this millennium, there's a decent chance it's already 3.3 or 2.5 V logic levels, which would be directly compatible with a Pico.
To drive a relay from a Pico, you'd use probably want to use something like a TIP120 Darlington transistor. In this case, the same circuit used for a 5 V Arduino will work generally work on a Pico, so I'd suggest using "Arduino" instead of "Pico" in a search. An important thing to note is that when a relay opens or closes, the magnet inside will generate a brief voltage pulse that will eventually damage your Pico. This is why most circuits you find online include an extra seemingly-useless diode; the diode shorts out the voltage pulse, protecting your microcontroller.
Converting 12 V to 5 V is easy. Get literally any random USB charger. Get a generic buck converter module. Use a LM358.
Statistics: Posted by DrDnar — Fri Jan 19, 2024 8:07 am