Wheel Encoder Set for AS-4WD Mobile Car
Sales Volume: 19
This quadrate encoder board is designed to hold two infrared reflectance sensors inside the hub of the 42x19mm wheel and measure the movement of the twelve teeth along the wheel’s rim. The two sensors are spaced to provide waveforms about 90 degrees out of phase, which allows the direction of rotation and providing four counts per tooth for a resolution of 48 counts per wheel rotation. Each analog sensor signal is fed to a comparator with hysteresis to provide glitch-free digital outputs.
The two outputs of the encoder are digital outputs which can be connected directly to digital input pins on most microcontrollers. With 48 state changes per revolution of the 42 mm wheel, a speed of 1 m/s (a bit over 3 feet per second) generates about 360 state changes per second. With two encoders used simultaneously, which is for most differential-drive robots, the encoders will require attention almost every millisecond. Decoding the encoder outputs should only take a few percent of the processing power of a microcontroller such as the Atmel ATMega168.
- 4.5V - 5.5V operating voltage
- 2 digital outputs
- 14mA consumption at 5V
- 48 counts per revolution (linear resolution just under 3mm)
- 2A continuous paralleled output current
- 100 kHz maximum PWM frequency
- 2.7-5.5VDC logic voltage