2 - Connections to the motor


Assuming that the motors are suitable for the job then let’s move on. My motors have 6 pins and are uni-polar so I can use an ohmmeter to work out which 3 pins correspond to coil 1 and which 3 are for coil 2 as described earlier. I can also work out, for each coil, which lead is the centre tap but cannot decide which is one end of the coil versus the other (ie cannot tell which is 1a and which is 1b).


I’m guessing that if I get this wrong then all that will happen is that the motor my move in the wrong direction. Using a ‘breadboard’ should help me find out the correct connection. So I wired each coil of my motor to a plug with the centre tap in the middle and the other two wires connected to the outside. This means I can rotate the whole thing through 180 degrees if I’ve got it the wrong way around! The plug I’ve used is polarised so that once I know the correct connection then I can solder the matching header onto my circuit the correct way around. In order to connect my plug to the breadboard I made up a short length of 3 way wire with a male header at each end – which will come in handy in the future for connecting sensors, servos, etc to the breadboard.



So here’s a picture of my motor, with wires, plug and the cable to link it to the breadboard:-