My Herbie photovore is whistling at me
Over the past couple days I constructed the 'Herbie' junkbot from MAKE (PDF here: http://cachefly.oreilly.com/make/mousey.pdf ). When I hit my 'on' switch I immediately start hearing a high-pitched whistle / squeal coming from the motor(s). When I read the voltages of them I get 0V on the left motor and ~8V on the right motor.
My LED, however, is nice and bright. I've checked and re-checked my solder joints and it all looks OK. I prototyped the circuit with the same parts on breadboard and had no problems (though I only used one of the motors, not both).