Motor wiring for Start Here Robot
July 1, 2011
Hello from a new member!
This is a great site - just what I needed. I just finished building the Start Here robot and... it worked!
Looking at all of the datasheets, I am confused by why the motors work.
I would have expected them to be driven off of digital pins 4-7 from area F (using the diagram at http://letsmakerobots.com/node/75).
They are wired in area G (the 2 A/B pin out areas). This was the plan but (q1) how did the output get there from pin outs 4-7? The Picaxe project board data sheet just shows 4 circles there without any description. I assumed it had to do with replacing the Darlington IC with the Motor IC but I couldn't find any documentation about that on the motor chips data sheet.
(q2) If I had left the Darlington chip in would the digital pin outs (area F) now work?
(q3) Can I use the additional power source (V2) for these area G (A/B) output pins without additional wiring (except for adding the additional V2+/gnd)?
PS I had a few other issues with the motors but solved them myself. In case any other beginners have the same thing, here's what happened.
First, the robot turned to the right because one motor was more powerful than the other. I read elsewhere in here that one of the motors could have been wired backwards so it was really in reverse. Of course, with the programming, this was overcome. But reverse might now be as strong as forward... for what it was worth, I attached a voltage source to each motor and determined that one was wired in the opposite direction and... it fixed that problem.
Second, the robot was a lot slower than Frits' -- I found that there should have been a jumper closing off the 2nd V2 power source. It's in the picture of his robot but my board didn't come that way. Maybe I missed the instruction but, putting that in, speeded up the robot.