Brake sensor (3 wire, Hall?) - operating the wrong way round

[pn_day]

Hi all,

I've got another naive question for the collective wisdom on this board.

I have extended a brake sensor cable (fitting into a recumbent velomobile, and the cable run was too long without extending). All seems good, except that the brake sensor only cuts the motor out (showing a brake indication on the controller) when the magnet is right next to the sensor. The brake sensors were kindly included by Woosh when I bought the GSM crank drive for use with an external controller. They are listed on http://wooshbikes.co.uk/cart/#/category/uid-4, described as a "pair of hydraulic brake sensors for BBS01/02".

I had to cut the end off in order to extend, and as it had a yellow 3 pin (Juliet?) connector, and the controller took 3 pin rectangular connectors (JST?).

I think I need it to operate the other way round - with the brake sensor cutting the motor when magnet is far away from the sensor. I attach an image of the control yoke showing the metal T-shaped brake lever (which operates 2 cable operated Sturmey Archer drum brakes on the front wheels). Not shown is the current cable-spaghetti that runs down it until I have everything working fully and tidy up!

Is it possible that I've connected something up the wrong way round? I thought it was just 5V, GND, and signal?

Thanks in hope,
Phil

 

[Woosh]

Hi Phil,

which controller are you using with the GSM?

 

[pn_day]

GSM being used with S12S controller with current decreased to ~13A, and the KT LCD3 display.

 

[Woosh]

confirm first the active signal voltage with a voltmeter - measure between ground and signal.

You should read 0V without the magnet and around 3.25V when the magnet is close to the sensor head like this:

 

[pn_day]

Thanks Woosh - I'll check when home from work.

 

[pn_day]

I get 3.2V when magnet is far away, 0 when close (blue to black). Red is definitely 5V.

The magnet end has red, blue and black wires. Can anyone confirm which is signal and which is GND?

Also is it a hall sensor or reed switch? If it was a red switch I could just connect to 2 wires (signal/GND).

Thanks

 

[Woosh]

Hi Phil,

Thank you for confirming the signal voltage of the brake sensor. So it is active high and unsuitable for your controller, you need active low brake sensors.

Something like this:

http://ebike-sales.co.uk/product/ebike-hydraulic-brake-switch

http://wing-ebikes.co.uk/?page_id=3002

I don't have stock of them at the moment, only for BBS01/02 which is wrong for you.

 

[pn_day]

Thanks very much for the clear help, and for suggesting sources.
Much appreciated
Phil