I bough this DC geared servo motor with encoder for an upcoming robotics project on Ebay. It was about 12$ shipped from China. There was little to no information available on the motor so I thought it would be beneficial to share my experience. The listing is for ESCAP 16 Coreless DC 12V 540RPM Gear Motor With Encoder 16MM.
|Motor +||Vcc||A||B||Gnd||Motor -|
The from the motor is a 6-pos DF13 cable.
|Model||16G 214E MR 19|
|Rated voltage||12 VDC|
|No load current||15mA|
|No load speed||540rpm|
|Motor output torque||0.143 NM|
|Shaft diameter||3mm (keyed)|
|Gear Ratio||27:1 reduction|
The scope capture below shows a nice standard 5V quadrature signal coming out of the motor. Notice that the voltage per div was different for the two channels during the capture. The rise and fall time are very quick (< 100 nano seconds). There appears to be a fair amount of backlash in the gear head. It appears to be something like +/- 10 counts. Also the motor shaft has a little bit of play laterally. Perhaps the bearings could be upgraded or replaced.
I plan to use these motors in conjunction with Pololu plastic wheels. Hopefully the slop in the output shaft and gearbox backlash associated with the cheap motor are not detrimental to the project.