I am trying to use the L298 H-Bridge with the arduino. There were schematics posted at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1180565927, but the picture hosting expired or something. Anyone have schematics for using the L298 with the arduino?
Also, is a heat sink absolutely necessary when I am just messing around with one small motor, or can I put it on once I move on to the larger motors?
Why don't you use the L293D? It is much easier... for just one motor...
I am using this with 2 motors which have already burned out an L293. I got the L298 because it was more than capable of handling the peak amperage of these motors, and the L293 is not. Plus, I already have the L298.
I was talking about using one small motor so I could mess with the L298 before setting it up with the two larger motors and heatsink.
You should be fine without a heatsink for small motors.
Download(and preferably print) the data sheet for the L298:
http://www.st.com/stonline/books/pdf/docs/1773.pdf
On the second page there's a picture showing the pinout, hook it up as shown, with the "INPUT" and "ENABLE" pins going to the arduino. Current sensing pins go to ground, you probably don't need resistors on them. IIRC, the pin setup is the same as the L293--Enable to high, and one input pin high and one low for direction control.
Take careful note of the schematic on page 6/13 of the L298 datasheet.
An L293D has back-EMF (flyback) diodes built in, but L298 does not.
You need to add them.
BTW, there are three basic ways to wire these up
Assuming you want to use PWM to give proportional speed control, you can put the PWM into enable, and use digital outputs, remembering pinMode(pin, OUTPUT), to drive direction.
As kunkmiester wrote, there is no need for sense resistors, just tie those to pins to ground.
But, if you have been having some pain with the motors, you might want to monitor the current through them. Put a low-value resistor (i.e. 0.1 - 0.2 ohm, low inductance) in the sense line, and measure the voltage drop with a multimeter, or Arduino analog inputs. Ohm's Law will tell you the current. If you use the Arduino to monitor motor current, you could shut down if there are problems.
HTH
GB