BuildInstructionsCorelessServo.md

Coreless servo modification (Turnigy MG959)

Part list

• 1 x Turnigy MG959 servo
• 1 x Adafruit ItsyBitsy M0 Express
  • https://learn.adafruit.com/introducing-itsy-bitsy-m0
• 1 x SparkFun Motor Driver - Dual TB6612FNG (1A)
  • https://www.sparkfun.com/products/14451
• 1 x as5048A + 6mm x 2mm comopatible magnet
  • https://ams.com/as5048a
• 2 x ITR8307
• 2 x 8.2 kohm resistor
• 2 x 120 ohm resistor

Cad and stl files for 3D printing:

CadFiles/ServoCoreless

Electrical schematic:

PcbDesignes/ServoCoreless

Build instructions

Build MainPcb and AS5048aEncoderBoard

A video on how to build the MainPcb and AS5048aEncoderBoard can be found at https://youtu.be/YQpAAr5RPSE?t=60. This video is for an older version but the building instructions are the same.

Servo gearbox with 3D printed parts

PCB Assemblies

How to mount the PCBs to servo

Build the Optical Encoder

1. Take the motor, use pliers to bend out the four indents in the metal housing and bend up the motor lid.

2. Remove the two steel brushes from the lid carefully by cutting the lid into pieces. Take the 3D printed motor lid and insert the two steel brushes and two ITR8307 into the new lid. Solder the ITR8307 according to:

PcbDesignes/Servo/OpticalEncoder/OpticalEncoder.sch

3. Take the motor with the lid removed. Paint the rotor with black nail polish and glue in the optical encoder wheel on top as shown in the middle image. The dimensions of the encoder wheel can be found in:

CadFiles/Servo/OpticalEncoderWheelDimensions.png

Then carefully put the new lid on the motor without bending the steel brushes.

4. Solder the four leads from the optical encoder on top of ItsyBitsy board as shown in this image.