Break sensor and pas sensor

Richarmed

New Member
Hi guys this is my first post.

I have a 3rd party brake sensor that detects the cable being pulled either at the caliper or lever end by running the brake cable through it. My question is as I only have one sensor(white) wire coming from my motor controller for my peddal assist, can I stem off this for the break sensor without it effecting how the pas works ?
 

harryS

Well-Known Member
Most PAS sensor cables are three wires, power, ground and signal. Some brake sensors are three wires, but most are two wire, brake and ground. You can't activate the brake function thru the PAS sensor,

What are you trying to dp?
 

JES2020

Active Member
Hi guys this is my first post.

I have a 3rd party brake sensor that detects the cable being pulled either at the caliper or lever end by running the brake cable through it. My question is as I only have one sensor(white) wire coming from my motor controller for my peddal assist, can I stem off this for the break sensor without it effecting how the pas works ?
It sounds like you do not have a motor wired for brake sensors. There should be a separate wire for the brake sensors.
 

rich c

Well-Known Member
It's really a motor inhibitor switch, not a sensor. It's either normally open or normally closed.
 

harryS

Well-Known Member
Some brake switches, like my Wuxing levers, use contact switches. I have one set that is magnetic, and it's a reed switch, because it would need three wires to use a Hall sensor.

In any case, I don't see any way to inhibit a motor by modifying the three PAS wires.
 

Richarmed

New Member
Most PAS sensor cables are three wires, power, ground and signal. Some brake sensors are three wires, but most are two wire, brake and ground. You can't activate the brake function thru the PAS sensor,

What are you trying to dp?
Hi Harry,
Thanks for replying. So what I am trying to achieve or hoping is that the single sensor wire coming from the motor would be able to act as the on off or just still sense the peddaling/not peddling and also cut off the motor when the brakes are pulled so the brake sensor wire does indeed come with three wires off it also just like the pas, this unissued is inwantbto use both pas and keep my old lever/shifters hence I am trying this and not using the two wire levers with the kit.
I think I am best to try it as again after thinking it will work then starting to doubt both sensors the pas work by allowing motor when I'm peddeling then when I stop after a delay the motor cuts off so mostly when I pull the break lever I will not be peddaling and pulling the break lever also shuts of the motor but instantly so I think if adapt a connection to run both pa sensor and break sensor to to run of the single controller sensor wire and the break remains red and black to the two pin standard break connector it may just work as now in my head nothing will shut off the motor until I either or both stop peddaling and hit brakes. Sorry for the waffle but I ideally did not wanna soilder another wire of my single existing controller sensor without know 100% haha but will defo have some solid knowledge on it after and will let you know. Just to clear up also this brake cable relys on a sensor to cut off when the cable is pulled
 

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Richarmed

New Member
It sounds like you do not have a motor wired for brake sensors. There should be a separate wire for the brake sensors.
Yes that is my issue but I am hoping as both pas and the braking in both cases you are trying to slow down that by them both being pushed through the same wire to the controller they will not conflict. I will attempt it anyways and be sure to let you all know the outcome :) thanks for your replies, appreciated
 

Richarmed

New Member
Some brake switches, like my Wuxing levers, use contact switches. I have one set that is magnetic, and it's a reed switch, because it would need three wires to use a Hall sensor.

In any case, I don't see any way to inhibit a motor by modifying the three PAS wires.
I suppose I'm only trying to shut off the motor so hoping that as standard the brakes will be having no impact on the circuit allowing the pas to have free rain until the moment I hit the brakes then that instantly hijacks it, I could be wrong and this could all just be wishful thinking 🙄 will let you know anyways I'm just finishing up soldiering a headlight that I have adapted to have a dimming function from using the control board from a old portable desk fan XD seems to work a treat.
 

Nick2

New Member
It should be possible to hijack the PAS signal using the brake switches, but you should be careful not to cause short circuit and damage the PAS sensor or the controler.
It depends also if the brake switch is NO or NC. If it is NO and closes when you squeeze the lever, you can use it to short the PAS signal to the ground, but it depends also on the PAS sensor - is it pull down, pull up or push-pull
design? if it is pull up or push-pull, you will probably need a resistor in series to avoid shorting the PAS sensor output. Alternatively, if the brake switch is NC, you can route the PAS signal through the switch.
And there is also the question of the controller reaction - does it stop the motor imidiately when you stop PAS signal or there is a delay?
 

Richarmed

New Member
It should be possible to hijack the PAS signal using the brake switches, but you should be careful not to cause short circuit and damage the PAS sensor or the controler.
It depends also if the brake switch is NO or NC. If it is NO and closes when you squeeze the lever, you can use it to short the PAS signal to the ground, but it depends also on the PAS sensor - is it pull down, pull up or push-pull
design? if it is pull up or push-pull, you will probably need a resistor in series to avoid shorting the PAS sensor output. Alternatively, if the brake switch is NC, you can route the PAS signal through the switch.
And there is also the question of the controller reaction - does it stop the motor imidiately when you stop PAS signal or there is a delay?
That routing idea is good to be fair, there is a delay so although currently it has not been a issue where I have been riding next Monday I will be back to work so want to get this up and safe before then 🤞
 

JES2020

Active Member
Hi Harry,
Thanks for replying. So what I am trying to achieve or hoping is that the single sensor wire coming from the motor would be able to act as the on off or just still sense the peddaling/not peddling and also cut off the motor when the brakes are pulled so the brake sensor wire does indeed come with three wires off it also just like the pas, this unissued is inwantbto use both pas and keep my old lever/shifters hence I am trying this and not using the two wire levers with the kit.
I think I am best to try it as again after thinking it will work then starting to doubt both sensors the pas work by allowing motor when I'm peddeling then when I stop after a delay the motor cuts off so mostly when I pull the break lever I will not be peddaling and pulling the break lever also shuts of the motor but instantly so I think if adapt a connection to run both pa sensor and break sensor to to run of the single controller sensor wire and the break remains red and black to the two pin standard break connector it may just work as now in my head nothing will shut off the motor until I either or both stop peddaling and hit brakes. Sorry for the waffle but I ideally did not wanna soilder another wire of my single existing controller sensor without know 100% haha but will defo have some solid knowledge on it after and will let you know. Just to clear up also this brake cable relys on a sensor to cut off when the cable is pulled
If you have the wires for the brake sensors and all you want to do is use your old levers, here is a much easier solution :

PS you can get them in a veriety of conectors of just splice them in.
 

harryS

Well-Known Member
Two-wire brake levers are normally open. Put a small resistor in series with the switch and put it across the PAS signal and the ground, and it will kill it. You will still have some lag from the motor that was spinning with the PAS, but probably not much,

You can do without the resistor, but it seems silly to put a short circuit on the sensor's IC output.
 

Richarmed

New Member
I carried on scratching my head and researching and earlier today just bottled it and fitted the ugly chrome oars that are the 2 wire kit breaks. To be fair I probably should of just accepted my fate sooner although it has made me want to learn more about circuitry and such.
Thats everyone for your inputs:)
 

harryS

Well-Known Member
OK, none of us understood your original questions. I didn't anyway., Your controller does have inputs for the standard two wire brake lever, but you bought a switch that mounts on the brake cable, allowing you to keep your good levers. Good idea. I agree with you about the quality of ebike brake levers supplied with kits. Lot of them are crap,

Anyway, the switch has three wires, not one white wire? Two of those wires are +5 and ground (red/black), You find them on your controller outputs. The white wire is the output. Probably goes from +5 to 0 when the sensor is activated.

Some controllers do have three pin brake inputs, which are +5, brake, and ground. If it only has two wires, one is signal and the other is ground. Determine which one is ground (use a continuity test) and then hook the sensor white to the other.