LED to power a DC motor

kitcha wrote in news:469eff8e-542a-4326-ba99- snipped-for-privacy@v5g2000prm.googlegroups.com:

An NPN transistor. The motor goes on the colectr side, between it and the load, the emitter to ground. The LED-s voltage goes via a resistor to the base. So long as both circuits share the same ground, this should work.

Another alternative is an N-channel MOSFET, like the IRF630. That will switch a strong DC current, and it's cheap, but it's likely you'll need more than the LED's forward voltage voltage on the gate, so tap the LED signal voltage before the resistor in series with that LED, so you get at least 5V on that gate, then it should work. (Though I suspect you might need 6V, or a MOSFET that will work with lower gate voltage).