Let's Make Robots!

Unusual servo movement in "start here" robot

Around a year ago I completed my version of the Start Here robot (with an SRF05) and have recently repaired it a bit (one of the motors wasn't working properly.) However, the servo now moves around a bit whilst my robot moves and sometimes even turns round fully to the left and just shakes. After playing around a bit, I figured out that the shaking only occurred when the output from the SRF05 was < 270 (about 45cm).

Motor Problem

I recently built the start here robot and was succesful and everything seems to work. I have one problem though that I don't know what the cause would be. The right motor (a solarbotics gear motor 9) runs slightly faster than the left motor and causes th robot to continually turn slightly to the left. Does anyone know how I could fix it or even add to the program to correct this?

Picaxe project board


First of all, sorry if this is in the wrong forum. But onto the question:

I've recently been designing my first robot, following the "start here" tutorial. I have most of it designed and drawn up in SketchUp, but the last thing I need to place is the project board (AXE020 for 28X1.) I have the dimensions of the board, but the one thing I would like to find out is whether or not there are any holes to screw the board down with, and if so where they are located (specific measurements if possible) and the diameter of the holes.

 Thanks in advance.