PCB Design and Testing

All of the circuity and PCB design was done using EasyEDA [1][2]. The microcontroller is powered from an external computer which is used so that the microcontroller does not lose power when the user stops pedaling. This issue has already been solved by Ergonomyx by using a battery and is therefore considered out of the scope of this project. A block diagram of the circuitry is shown below.

The circuitry and the corresponding PCB is composed of the microcontroller, 3.3V regulation for the microcontroller, a AC-DC half-bridge rectifier, regulation components to step the high-voltage from the generator down to 5V, a volt-meter for real time voltage level feedback, and PWM logic circuitry. A USB-TTL converter is used from the UART data lines to boot the code and display serial information on the computer. This is an external component that did not need to be designed or added onto the PCB.

The circuit can be split into both the circuitry required for the 3-phase generator and the circuitry required for the microcontroller. Both of these circuits are almost independent of one another as the 3-phase generator is only used for generating the power for the motor. The microcontroller circuitry is shown below.

Microcontroller circuitry

3-phase generator circuitry

---

The PCB wiring was also done in EasyEDA

Unsoldered PCB:

Soldered PCB: