Components Previously on the PCB

The printed circuit board has many components that have been deemed obsolete and removed. Below is a list of those components, how they worked, and why the were removed.

Components Removed In Spring 2020

Prior to spring 2020, the PCB was designed for use by both CUBike and CUSail, resulting in many parts that were not necessary for the functioning of the bike. In Spring 2020, a major overhaul was started in part to remove many of these unnecessary parts.

Watchdog

The Watchdog is an external timer circuit that assured the Arduino DUE was correctly executing its loop. The Watchdog’s timer was reset each time the DUE successfully completed a loop. However, if the DUE’s loop execution was unsuccessful, the Watchdog’s timer would not be reset, causing an emergency shutdown and preventing damage to the bike’s systems.

The Watchdog connected to the PCB through three pins, labeled WD+DPINS, and an op-amp.
WD+DPINS
PIN LABEL CONNECTED TO
1 DUE pin 45
2 DUE pin 43
3 Op-Amp pin 1 (WDO)
Associated Op-Amp
PIN LABEL CONNECTED TO
1 WDO WD+DPINS pin 3
2 GND GND
3 EN DUE pin 41
4 WDI DUE pin 42
5 VCC C35 --> GND

The Watchdog and associated hardware were removed because an unsuccessful loop execution by the DUE was deemed to be an unlikely source of failure.

Additional Components Only Used by CUSail

Sail Motor

The old PCB contained outputs for the sail motor and bike motor. Since the bike is not a sailboat, the sail motor outputs were removed.

Sail Power

Similar to the sail motor, only the bike power output is necessary.

Xbee Pro

The Xbee Pro was used in conjunction with CUSail's remote controller. The bike uses a different controller.