Hi,
I need some inspiration.
I need a simple way to sense when I'm pulling the brake lever on a bike. Ideally with some sort of feedback on how large the tension in the wire actually is.
So far I have thought of this:
* Hall sensor at the brake lever
It's simple enough, doesn't need re-calibration as the brake pads wear down, but I would have to glue the sensors to the handles. Potentially looks messy. To get some sort of feedback on the wire tension, I'd have to use multiple sensors.
* Load cell inserted into the brake wire
That's a massive safety issue and I really don't like it. If I could deal with the signal (and fluctuations due to vibration), I'd have a real feedback of the tension in the wire.
* Load cell in parallel with the brake wire
I suspect the signal would be even smaller, much more SNR problems. Not ideal at all.
* Hall sensor underneath the brake wire + magnet attached to the wire
Would need some sort of guide to keep the wire from oscillating side to side. Would also need re-calibration as the brake pads wear down. Not good.
* Direct measurement of the wire tension
Similar to this geometry. To keep it small, I guess I could only use a tactile switch instead of a real force sensor. Would need proper initial calibration (moving parts), possibly issues with the switch after a while.
* Accelerometer
This would be the last way out, but I really don't like it. It only works if the velocity of the bike is > 0.
What else could be used?
It should be safe, simple, clean and reliable.