DC 12V DIY Encoder Gear Motor 65mm Magnetic Gearbox with Motor Mount Bracket Engine Wheel Kit Micro Speed Reduction Motor Full Metal Gearbox for Smart Car Robot Model DIY(500RPM),Geared Motor

The motor and encoder were of good quality, though no gear ratio or encoder specs were gave. Here are the specs that I calculated from the motor and encoder I received. The encoder works out to 22 pulses per revolution, and 342 pulses per revolution at the wheel, with a 1:15.5454 gear ratio. Hope that helps.

I bought two of these to use in a robotic car project by ArticulatedRobotics. The encoder provides a very clean and consistent pulse (although only 11 counts per revolution). Nothing special about the motors, they work fine. It’s very handy that the kit comes with mounting hardware for the motor and a wheel attachment that is very secure and doesn’t wobble. I agree with a previous reviewer that specs should have been provided for the encoders. The trace below shows the encoder outputs. The trace was obtained with 12V to the motors and 5V to the encoders. The yellow trace is Channel A and the purple trace is Channel B. Using an Arduino Nano and encoder software, and turning the output shaft by hand, I measured 656 counts per revolution of the output shaft for 15 revolutions of the motor shaft. Assuming the count was probably 660, it works out to 44 counts per revolution of the motor shaft. Since this is a quadrature encoder and the manufacturer specified 11 counts per revolution, it seems like the manufacturer meant 11 pulses per revolution (which must be multiplied by 4 to get counts per revolution). Since the output shaft speed is 500 RPM, the motor must be turning at 500 x 15 = 7500 RPM. With a 3V input to the motor I measured a no-load speed of about 120 RPM (probably 125) and a current draw of 70 mA. With 6V applied to the motor, the speed was (probably) 250 RPM with a current draw of 90 mA, and for 12V the rated speed of 500 RPM drew 130 mA, no load. I didn’t measure the stall current. My only reservation is that the motor output speed is high for a robotic car, but running it at a lower voltage should compensate. Good product.

Pretty decent for the price and accurate enough with medium distances (under 50ft)

Motor worked well, had good torque, but the product seller didn't add a datasheet. No information available about the gear ratio or the pulses per revolution.

Kind of useless having an encoder if the specs are kept a total mystery.