This kit includes two dual-channel Hall effect sensor boards and two 6-pole magnetic discs that can be used to add quadrature encoding to two mini plastic gearmotors (motors and cables are not included with this kit). The encoder board senses the rotation of the magnetic disc and provides a resolution of 12 counts per revolution of the motor shaft when counting both edges of both channels. To compute the counts per revolution of the gearbox output shaft, multiply the gear ratio by 12. This compact encoder solution fits within the 11.5 mm × 22.5 mm cross section of the motors on three of the four sides, and it extends approximately 5.5 mm past the edge of the fourth side.

The encoders include a side-entry, 6-pin male JST SH-type connector with a 1mm pitch that is compatible with our 6-pin JST SH-type cables. We also carry a version of this encoder with a top-entry connector; the following pictures show a comparison of the side-entry (left) and top-entry (right) versions:

Magnetic Encoder with Side-Entry Connector             Magnetic Encoder with Top-Entry Connector

on a Mini Plastic Gearmotor (cable not included).      on a Mini Plastic Gearmotor (cable not included).

Cable options:

We have two types of cables with matching JST SH-style connectors that can be used with these encoders. Single-ended versions have a connector on one end and unterminated wires on the other, while double-ended cables have twisted wires with female connectors on both ends.

The double-ended cables can be used with our JST SH-style connector breakout boards (available in top-entry and side-entry versions) to easily access the motor and encoder pins on a standard solderless breadboard. The right picture below shows an example of this with our similar micro metal gearmotor encoder.

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Pinout and installation:

The encoder board is designed to be soldered directly to the back of the motor, with the back shaft of the motor protruding through the hole in the middle of the circuit board. One way to achieve good alignment between the board and the motor is to tack down the board to one motor pin and to solder the other pin only when the board is flat and well aligned. Be careful to avoid prolonged heating of the motor pins, which could deform the plastic motor case or the motor brushes. Once the board is soldered down to the two terminals, the motor leads are connected to the M1 and M2 connector pins as labeled below, and they can be accessed via the red and black wires when used with our corresponding JST cables. The remaining four connector pins are used to power the sensors and access the two quadrature outputs:

• Pin : Wire color : Function
• 1 : Green : encoder GND
• 2 : White : encoder channel B output
• 3 : Yellow : encoder channel A output
• 4 : Blue : encoder Vcc (2.7 V to 18 V)
• 5 : Black : motor power M2
• 6 : Red : motor power M1

Encoder A and B outputs of a magnetic encoder on a high-power (HP) mini plastic gearmotor running at 4.5 V.

Schematic diagram:

Comparison to older versions:

This encoder module improves on our previous encoder boards for mini plastic gearmotors by adding a connector to enable the use of removable cables. The basic schematic is unchanged, and the electrical performance is identical aside for the lower minimum operating voltage. The following pictures show the two newer encoders with JST SH-type connectors next to the original ones:

                        

Magnet-side view of the          Magnet-side view of the           Romi Encoder Pair Kit,               Magnetic Encoder Kit for Mini Plastic 

Magnetic Encoder with          Magnetic Encoder with               magnet-side view of PCB.         Gearmotors magnet-side view of PCB.

Top-Entry Connector for        Side-Entry Connector for 

Mini Plastic Gearmotor,        Mini Plastic Gearmotor,

12 CPR, 2.7-18V.                    12 CPR, 2.7-18V.

Package Includes:

• 1 x Pololu 3547/3546 Magnetic Encoder Pair Kit with Side-Entry Connector for Mini Plastic Gearmotor, 12 CPR, 2.7-18V