I am trying to design an e-assist handcycle for quadriplegics who do not have enough grip strength to squeeze a brake lever. We generally use a coaster brake instead. Are there any ebrake sensors that work with a coaster brake? In other words, can detect if the user pedaled backwards and intends to stop the bike?
Coaster brake ebrake cutoff sensor
- Thread starter eecsflyer
- Start date
MadRhino
100 GW
Easy to fit a momentary switch to the brake hub lever. Those hubs have a torque lever that usually attach to the derailer mount. If you give it 1/4’’ play and a return spring, you have enough movement to trigger a momentary switch.
Alternatively, there are brake light switches that are actuated by cynetic energy sensor (or G sensor if you prefer). Some are pretty cheap and can be used to trigger the ebrake cut-off with very little mod. Then your ebrake is automatically engaged and the brake light automatically lit when you start braking. :wink:
Alternatively, there are brake light switches that are actuated by cynetic energy sensor (or G sensor if you prefer). Some are pretty cheap and can be used to trigger the ebrake cut-off with very little mod. Then your ebrake is automatically engaged and the brake light automatically lit when you start braking. :wink:
MadRhino
100 GW
TDB said:
Most if them since they exist are clamping to the frame. Many recent models are bolted to the derailer hanger. But, all of them have a torque arm.
Chalo
100 TW
TDB said:
Single speed coaster brake hubs have their torque arms attached to the left side axle cone. They can't move back and forth without loosening the hub and causing problems.
Multi-speed coaster brake hubs usually have torque arms that are captive but not rotationally locked to anything other than the brake expander cone. This could hypothetically be used to actuate something, if as MadRhino suggests you provide a spring return of some kind. Braking force on the torque arm can be very high, so it must be firmly retained.
I once had a plan to use the brake arm of a two-speed automatic coaster brake hub to actuate a cable running to the front brake. I never did work out a good way to extend, travel limit, and spring return the arm for this application, but I guess I could return to the project one day.
LewTwo
1 MW
Chalo said:
Well if you ever decide to follow through on that ....
Epoxy an strain gauge to the surface of the strap holding the arm. You would also need a small mpu and some electronic glue but it could be a workable scheme.
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