Element14 has a great YouTube vid on transistors, and I get that transistors are faster than relays and are better in low voltage situations. But I've been trying to custom build a motion sensor that remotely turns on the motor of an animatronic prop. It should be easy enough to activate that motor from the collector side of my transistor.
But because the prop is a distance away (maybe 5-6 feet), it has it's own power supply and a separate ground. All I really need is something to close the circuit on the ground side of the prop motor. So it seems to me that two wires from the prop to a remote relay, NOT a transistor C/E connection, would make more sense. The activated motion sensor would send 3.3v to the relay. Then the relay connects the two wires together and that completes the motor circuit.
I've been trying to do this with a transistor switch for days and can not figure out what I should be connecting to the motor two wires.
Has anyone else tried to rig a simple remote switch like this? (Halloween props typically use foot pads that complete the circuit in a similar but highly mechanical way.)
