Magic Pie 5 - Inline Mechanical Brake line sensor malfunction

[Mhawel]

Hi Everyone,

I've had a couple of sensors that worked fine while I had them installed at first, but one seems to have stopped working suddenly, and I'm not sure why. The left brake sensor (not that location matters) is still functioning, and both LEDs on the sensors light up when it is triggered, and the motor shuts off accordingly. But when the right brake is applied, nothing happens with the LEDs, and the motor doesn't get cut off.

It seems a ring magnet follows the brake line and triggers a hall effect sensor at one end, so I'd imagine contact cleaner wouldn't have any effect, given there are no actual contacts being made. Also, the magnet movement can be felt hitting the end as you slowly actuate the brake lever. I've also loosened off the cable from the brake, and slid the sensor housing along the brake cable to verify the maximum amount of play necessary, and the switch still doesn't work, but the magnet can be felt hitting both extents internally.

I know that both sensors must be installed or removed for the motor to function at all. You can't run just one sensor. Unfortunately, that's all I know regarding this sensor.

The sensors were purchased from the Golden Motor Canada website a number of years ago. I only got back onto my bike and started pedaling to test out my back's reaction recently, and realized I hadn't yet installed the sensors. They worked perfectly when they weren't installed, and I tested the operation of both with a new brake line I am now using due to the extra length required by the sensor.

So happy to be back to pedaling again! (Also very happy to have the silent Magic Pie assisting me when I need it)

[Ron Burgundy]

I think the brake sensor is a simple open/closed circuit loop. I think the brake circuit must be a "Normally Open" circuit when nothing is connected. When the brake sensor is connected, in order for it to still be an open circuit, the magnet would have to be keeping the circuit open, which is the normal state of your brakes when they are not being applied. If the magnet is removed, the circuit closes and triggers the brake. You can test that theory on the one that is working by removing the magnet. In order for the other brake lever not to trigger the brake when the magnet is removed, the wire or that circuit is open somewhere.

Happy Hunting

[Mhawel]

Thanks for the reply! I'm going to test it with my meter and test leads once I have a chance, and remember to bring it home with me. The sensor will need to be powered as well, so I need to sit down with it for a bit rather than just fiddle with it while it's attached to the bike...

I can't just remove the magnet unless I open the sensor housing, because the inline sensors are fully enclosed, unlike some of the of the other sensor designs I've seen pictures of...

Mike