A pair of optical quadrature sensors, designed for installation in micro motors from Pololu from the micro series with bilateral shaft. The set consists of two boards with integrated optical sensors and impeller with five or three blades mounted on the front-end motor shaft is. The sensor allows to obtain a resolution of 12 or 20 pulses per revolution, depending on the selected number of blades.
The sensors only work with the Pololu micro motors equipped with bilateral shaft series: HP, MP and LP. They are not cooperating with a series of HPCB.
The operating principle of the encoders
- Supply voltage: 5 V
- Current consumption: 12 mA
- 3 blades: 12 impulses per revolution of the engine*
- 5 blades: 20 impulses per revolution of the engine*
- Dimensions: 9.6 x 11.6 mm
- Weight: 0.7 g
- 2 x board with sensors
- 2 x impeller with 3 blades
- 2 x impeller with 5 blades
* The given resolution is the number of impulses per revolution of the engine. To count the impulses per revolution of the output shaft (wheel), multiply the specified number by the selected position. For example, for engine with the 30:1 gearing with the mounted five blades, the resolution will be: 20 * 30 = 600 pulses per revolution of the output shaft with gear.
Installation and connection
The board with sensors are designed for direct soldering on the power pins at the rear of the engine. The corresponding alignment of the module is the key to receiving the output signal of the high quality. One of the ways of the board installation, is to solder one end, then the align the module and solder the second pin. It is necessary to avoid prolonged heating of the pins of the engine as it may damage the plastic case.
The mounting holes of the module are simultaneously power pins of the motor, connected to the M1 and M2 pins. OUT1, OUT2 pins are the quadrature outputs. Sensor's power supply of 5 Volts must be connected between pins VCC and GND. Pins are applied to the board that have a distance of 2 mm which provides the connection with a suitable multicore tape.
When the module is properly soldered, on an extended shaft must be applied an impeller with selected numbers of blades. Item must be put on in such a way that the gap between the sensors and the blades was approximately 0.5 mm. One of the ways of equal installation is the use of washers with a thickness of about 0.5 mm, for example, business cards or a few sheets of paper. The best method is to use the oscilloscope to view the output signal.
Oscillograms in the 5 V version. At the left blade, too far from the sensor, at the right, too close.
Oscillogram for 5 V version. The optimum distance between blades and sensor.
Oscillograms in the 5V version. At the left blade, very far from the sensor, at the right blade, extremely close.
Version 5 V and 3.3 V
In our offer, available is also the version that works with voltages of 3.3 V. The modules differs in configuration elements powering the IR LED and the current consumption. 5 V board consumes about 24 mA, version 3.3 V - 12 mA.