Motors, more motors and a couple more motors

For a while I have been considering different motors and to use with the modular robot, the various drive options avalible include; servo motors, geared motors or ungeared motors. While wheels include; small wheels, tracks, or bare motor shafts (possibly with a small amount of heatshrink for traction).

The very first Edgebot I built using spare parts and about 20 minutes, more importantly however, is that I used geared servo motors and small Lego wheels connected using a large amount of hot glue (I really don't refrain from using hot-glue :D) Although the end result had a reasonable amount of torque, it was quite slow and the amount of work that was required to both 360 degree hack and DC (rather than PWM) hack the servo did not make it a fast and easy process. Also, even the cheapest servos are relatively expensive.

You can see the servo motors at the back, along with the crudely attached wheels.
It is not my circuit design; the original circuit design can be found here

Where servos are slow and high in torque, ungeared motors are very fast (7000rpm) with hardly an torque (the stall torque of most small, ungeared motors is about 15 grams) Therefore making them handle wheels poorly, as they simply stall and drain the batteries quicker. However, people often attach heatshrink to the motor shafts and use them on lighter robots which require high speed movements.

The final type of motors are the geared motors, which are similar to servo motors, but typically have a lower gear ratio so that they travel faster. Unlike servo motors, geared motors do not require any hacking to make them function as robot wheels. Geared motors are the same price as, or slightly more expensive than, servo motors, but as they require no work for them to function correctly, it would typically be worth it.

For the modular robot chassis, I am going to try some of each to see how well they work (or don't). For the servos, I am going to use standard, lightweight servos from Hobbyking. The Solarbotics' motors are often suggested for use in robots, so I'll test them also. While for the geared motors I am going to try some standard geared motors as well as a pair of offset shaft motors, which should work with these tyres, these are again, from Hobbyking. The reason I am using Hobbyking is that I frequently place orders with them for RC supplies and the like. 

I shall post results once I received and tested all the motors.