I am looking to control a DC motor using my Arduino and an L293NE H Bridge (http://focus.ti.com/lit/ds/symlink/l293d.pdf). From what I can tell the voltage supply is 4.5-36V.
The motor I want to control is rated 1.5-3V (1.5V Recommended).
Is this possible or is the motor too small?
It is possible. You want to use pulse-width modulation (PWM) to rapidly apply/not-apply voltage to the motors to control the amount of EFFECTIVE current you are delivering. Even with a 12V power supply, if your PWM waveform has a duty cycle (ratio of on-time to total period) of 25% you are only delivering an effective current that corresponds to about 12*0.25=3V of steady DC voltage.
ok, I just wasn't sure if the L293 would be able to supply < 4.5V. I could also use PWM to control the speed of the motors by using an even shorter duty cycle right?
The L293 won't be supplying <4.5V. In fact, it will supply 12V (in my example) but only 25% of the time, the other 75% of the time it supplies 0V.
Varying the duty cycle varies the effective current, and will therefore vary the speed, as you require.
Gotcha. That makes total sense now. Thanks for explaining 