I'm trying to use an Arduino to release a single drop of water using a solenoid valve. This article describes how to create this circuit with a Raspberry Pi using a DC powered solenoid that opens and closes very quickly and they use this for photographing water drops. Exactly what I need, if I could only get it to work with the starter kit items first.
The design for the solenoid circuit from that site looks like:
I don't have a solenoid yet, but I've been experimenting with the cheap motor that comes with the Arduino and a 9 V battery. I've burned out several transistors in my attempts to get this working. My schematic looks like:
Relays won't work. They are too slow. Also, I need to use an external battery. I can't use the power from the Arduino because I will eventually be moving up to a 12 V battery and the Arduino won't be able to handle that.