Coil Winder provides the capability to wind custom pickups for electric instruments.
Source code and project files: https://github.com/reubenstr/CoilWinder
The electronic control systems allows for setting various parameters such as number of turns, RPM, indexer start and stop heights, etc.
The indexer assists in making the coil windings evenly distributed on the bobbin/pickup.
The custom pickup, in black, is attached via set screws. This system allows for custom holding brackets to be designed and printed to support a wide variety of pickups. The lowest portion contains two magnets triggering the hall-effect sensor to provide RPM feedback.
The control systems ramps up the RPM when starting the winding process to avoid wire breakage. RPM is honed in using a simple PID controller.
A custom PCB was created to ensure good working order of the electronics.
The electronics contains a Arduino Nano, A4988 stepper driver, TB6612FNG DC motor driver, a buzzer, etc.
The PCB and power supply is mounted under the control panel. The frame is generic 2020 aluminum extrusions providing a heavy sturdy frame.
Behind the control panel is the expected wires. The LCD uses a I2C to LCD conversion module for wire reduction and Arduino library support.
The winding motor is a 1000RPM 12vDC gear head. The indexer uses a generic NEMA 14 stepper motor.
Prior to creating the PCB a breadboard test bench was created to ensure the electronics worked as intended.
After thoughts:
Several custom pickups for my Melodic Chimes project were created successfully with ease.
The intention was making a coil winder that could be easily fabricated for budgeted enthusiasts with simple components, easily 3D printed parts, ready designed PCB, and complete firmware. Much of those goals there is success, however, due to the skill set, parts, and equipment required to construct the frame, the project fails to provide a easy to make coil winder for the average hobbyist.
Success could be found in designing the frame that is able to be constructed from range of materials requiring common skill sets and tools. For example, the 3D printed parts could be redesigned to mount on a flat cut of plywood.
The electronics could also be improved:
Due to the low power requirement the AC-DC power supply can be removed and a wall mount power supply could be used. A DC barrel jack could be added to the PCB.
A PCB could be designed to hold the control panel buttons and LCD making wiring less tedious. The start/pause/buttons could be replaced with PCB mounted buttons.
The winding motor could be replaced with a brushless motor allowing for faster winding RPM and quieter operation. Using a brushless motor may eliminate the need for a hall-effect sensor as some motor drivers provide RPM feedback.
A hinge could be added to the indexer allow for safer and easier storage of the coil winder. Or, the indexer could be redesigned to remove the lead screw and use lever arm or a 5-bar linkage system.
The firmware could be modified to include saving and retrieving winding profiles.
