We just received a new shipment of motors in for our Traxster robot kits, and I wanted to put a few notes on the forum about them:

They are much higher quality than the previous motors, are much more quiet (due to more precise gearing), and have built in quadrature encoders on them.

The specs are:

• 7.2 Volts
• Gear Reduction: 1:52
• Stall Torque: 100 oz-in
• Max Speed: 160 rpm
• Quadrature Encoders built in with 12 pulses per revolution resolution (This means 624 pulses per wheel revolution)
• 12" motor wire lengths
• 12" encoder wire lengths with plugs (which can plug directly into the Serializer)

NOTE: For those customers who are using a CMUcam2/2+ Pan/Tilt turret or an IR Panner with their Traxster, you will have to remove the black plastic encoder cover for the motors to fit.

On another note, I measured the current draw between the old motors and the new ones, and found some interesting results.  The old motors were very noisy, and top speed varied between the motors (due to frictional differences - imposed by manufacturing).  The new motors are very quiet, precise, and top speed seems very consistent.  So, once I measured the current draw between the two (almost identical) motors, the old motor were pulling about 750 mA at no-load top speed, while the new motors pulled around 300mA no-load top speed.   Wow!

Traxsters will now come with the quadrature wheel encoders on the motors, so there won't be any need to purchase the optical encoder modules for the Traxster going forward.  We will continue supply the optical encoder modules, however.

The PID values will change for the Traxster (since the quad encoders have a higher resolution), and we will post those values in a few days.