4.4 Assistance monitoring
A key feature of the electrically assisted bike is that the rider can
choose to have assistance with pedalling. On both bikes, riders can
switch the pedalling assistance on and off, and are able to change
the assistance level that the motor will provide. This level of
assistance (low, medium or high) is chosen with a button interface
attached to the handlebars.
The two e-bike models feature very different designs for the
controller system, so different methods were used to monitor
assistance on each bike. The Velo-cité used the local interconnect
network bus serial protocol [23] to communicate between interface
and motor controller. The bus was connected to a UART port on
the IOIO, and software on the phone monitored commands from
the handlebar interface to detect assistance level changes.
Monitoring assistance on the Dover was less straightforward as we
had no prior information about how the interface communicated with
the controller. An experiment was conducted to explore the voltages
on the eight wires that run between interface and controller, and two
wires were found whose reading were indicative of assistance levels.
The voltages on these wires are monitored using analogue inputs on
the IOIO