EDN magazine has a design
idea for a low-power (3-12v) dual dc-motor controller for use in
mobile robots. The article includes a schematic
and a source
code listing in PDF format. The circuit pulses left and right motors
alternately, moving the robot in a unique zig-zag fashsion that can be
used to continously correct for course deviations.
I saw that article in EDN but I have a big problem with it. The transistor is a 2N3055
which is a power transistor. Notice the 33 ohm resistor to the base - there is no
way that a normal printer port can supply that amount of current. Now if you want
to drive only 100ma or 200ma then replace the 2N3055 with a small 2N2222
transistor and replace the resistor with 220,330, or 470 ohm resistor. But if you
want to drive more current then you'll need a buffer between the printer port
and the 2N3055.
Roger robot, over and out.