[Lee Willis]

Maybe GRJ or someone here has worked with smaller, but this is the smallest electric motor I have ever working with. I took apart one of the small, inexpensive reomote control cars to pirate parts for a home-made wire-guided car, and this was its motor. 1.5 volts, probalby puts out 1 nano-horsepower.

 

[Millstonemike]

Lee, there's these cheap remote control cars from China: < $10. They're 3.15" long (scale 12.6'). They may provide a source for powered chassis' as they have articulated steering. They're remote control but that could be bypassed (or leave the throttle function for little ones coming to play ). The cars have a rechargeable battery, and, I believe, they recharge via attachment to the remote. The remote uses two AA batteries. There's others out there as well. Link

 

[Norton]

Thats pretty small. I have some 6mm gear motors that are about the same size as that pencil. That one appears even smaller. Hopefully those gears never bind or the car hits a wall or the stall current will smoke that motor instantly.
This the 6mm gearmotor. The black section houses a 760:1 gear reduction. The screws are 2-56 for comparison. Pololu.com is one source for these.

Pololu Plastic Gearmotors

A variety of low-current brushed DC motors with plastic gearboxes that offer power and speed comparable to a continuous-rotation RC servo at a fraction of the price.

www.pololu.com

Pete

 

[gunrunnerjohn]

I have a couple of the gear motors that Pete shows, and I also have an assortment of tiny motors, some even smaller than Lee's motor.

 

[tkruger]

I have some tiny pancake ones from a miniature drone. They to charged off the remote.