Motors, Wheels and Encoders

Robot propulsion is based on basic RS04 kit from Dagu. The kit includes 2 wheels with soft rubber tiers and 2 magnetic encoders. Tires are driven by geared DC motors. To stabilize the robot, we use a ball caster that support rotations in 360 degrees.

Dagu RS04 Motors, Wheels and Encoders kit

Description

The magnetic encoders consist of two Hall sensors together with the magnetic shields to be mounted on motor shafts. Sensors change the status (from high to low or from low to high) several times per revolution of the motor shaft (see specs).

Note: To read sensor values, you should apply a resistor pulling-up to VCC, for example, 10 kΩ.

Specifications

Geared DC Motors

  • Voltage: 3V to 6V DC
  • No load Current: 200mA
  • Stall current:
    • 3A at 6V
    • 1.5A at 3V
  • Gearbox ratio: 118.5:1
  • Wheel Speed: 135Rpm at 6V unloaded
  • Dimensions: 55 x 48 x 24 mm

Encoders

  • Resolution:
    • 8 state changes per revolution when mounted on the output shaft
    • 948 state changes per revolution when mounted on the motor shaft
  • Hall-Effect sensor with open drain:
    • Short circuit protection
    • Reverse polarity protection
    • Maximum Output Current: 25mA
    • Voltage: 3V to 24V
    • Consumed Current: 4mA
  • Neodymium Disc Magnet:
    • Poles: 8
    • Diameter: 20 mm

Encoder Cables

Each Hall-effect sensor is soldered to a 3-pin cable with a female goldpin connector (2.54 mm pitch). The connector has the following pins:

  • Red- supply voltage (VCC) in the range from 3 to 24 V
  • Black- ground of the system (GND)
  • White- impulse output of a Hall sensor

Wheels

  • Diameter: 65 mm
  • Thickness: 26 mm

Ball Caster