I’m looking to build a vibrating magnet detector around the size of a watch face if possible. I have a neat idea but this would need to be made before the idea takes off.
It’s going to be hard keeping it the size of a quarter. But it is doable… With an Atiny85 some driving circuitry, it may be possible if you’re good with SMT components.
If you want, I could draw up a schematic fairly quickly. I may go ahead and do it so everyone else can use it…
Here ya go. This circuit is everything you need to run the motor and has the Sparkfun Reed Switch to Ground. You can program the '85 with a ICSP programmer or another Arduino if you have one. The only thing you need to add is the battery and motor (and the components of course). Note that this circuit has the '85 running at 8MHz so your code needs to reflect this due to timings. The code would be rather simple as well… Just make sure to burn a bootloader that will set the correct fuses and for the 8MHz internal oscillator.
Now you can see that the circuit will make it hard to be the size of a quarter but it is possible with SMT…