Fitting PAS sensor to Claris Double - help please

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
As you have access to the sensor PCB, you can unsolder the wires and resolder in the right places. Once desoldered, you can check them with a meter to see which is which. That'll keep the wiring and connectors nice and neat.

Actually, you don't need the connectors. They're only there to make the installation easier, though inevitably they lead to problems. You have the option to cut off both connectors and solder the wires together. That will be more reliable in the long-term and has the additional advantage that you can adjust the cable to just the right length. In the rare event that you'd ever need to dismantle for some reason, you can cut it again and resolder in seconds.
 

FoolThrottle

Finding my (electric) wheels
Sep 17, 2019
11
0
As you have access to the sensor PCB, you can unsolder the wires and resolder in the right places. Once desoldered, you can check them with a meter to see which is which. That'll keep the wiring and connectors nice and neat.

Actually, you don't need the connectors. They're only there to make the installation easier, though inevitably they lead to problems. You have the option to cut off both connectors and solder the wires together. That will be more reliable in the long-term and has the additional advantage that you can adjust the cable to just the right length. In the rare event that you'd ever need to dismantle for some reason, you can cut it again and resolder in seconds.
OK, I am trying but pretty poor from my end to be honest.
I have left the julet to the controller and then cut halfway through the pas sensor wire assuming I could just rewire that half way along to change them round?
Using a voltmeter at controller end I get.
Red and blue 5v
Red and black 0.7v circa
Blue and black 4.3v circa

I have tried each combination but none result in a solid red light on the pas sensor.

:( again, thanks if you can steer me the right way.
 

Attachments

Nealh

Esteemed Pedelecer
Aug 7, 2014
19,991
8,173
60
West Sx RH
On both sensors black is Gnd, Red/Brown are 5v and Yellow /Blue are signal.
The sensor LED should only show an on /off signal as a magnet passes by it.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
Unfortunately, you haven't made it clear which way round you measured, though the measurements definitely show that the wires are wrong. What you should do is put your black probe on the battery ground anywhere, which is on any black wire except the one you're measuring, then put your red probe on each of the three wires on the controller side. You should get 5v, 4.7v (signal wire) and 0v (ground). You then connect the 5v to the red or brown wire, the 0v to the black and the signal to yellow or blue, depending on which of the two sensors you're using.

It looks to me like your blue and black are crossed over, so red is 5v, blue is ground and black is signal. Those fit your results, but you need to measure again like I described to be sure.
 
Last edited:

FoolThrottle

Finding my (electric) wheels
Sep 17, 2019
11
0
Unfortunately, you haven't made it clear which way round you measured, though the measurements definitely show that the wires are wrong. What you should do is put your black probe on the battery ground anywhere, which is on any black wire except the one you're measuring, then put your red probe on each of the three wires on the controller side. You should get 5v, 4.7v (signal wire) and 0v (ground). You then connect the 5v to the red or brown wire, the 0v to the black and the signal to yellow or blue, depending on which of the two sensors you're using.

It looks to me like your blue and black are crossed over, so red is 5v, blue is ground and black is signal. Those fit your results, but you need to measure again like I described to be sure.
Numpty alert. Sorry, still failing..
My steps
Plugged pas into correct controller wire from battery.
Cut pas wire in half and exposed ca le both sides.
Measured voltage of wire pairs as earlier from controller end (other end of cable no longer attached to anything.
Twizzle controller end to pas sensor end but couldn't find a combination that permanently turns light on the sensor so assuming incorrect.
Measured each combination and can't find any wires that are 5v.
Unsure if I have done something incorrectly and have no other exposed wires to use ground as suggested. Do I plug a spare cable in eg brake lever though I'd have to cut that.
Thanks
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
This is one of the problems of systems with sealed connectors. It's really tricky to find contact points for testing and diagnosis, which is why I prefer and advise people to use kits with conventional block connectors. Guys like me that fix these systems regularly have spare connectors with flying leads cut off the defunct ones. For a universal ground, I'd use a spare 5.5mm jack in the charge socket. Don't try and stick your meter probe in there because it's too easy to short it.

If you can't find a universal ground, you can still measure between the three wires, but you have to say which way round the voltage is, i.e. which wire the black probe was on and whether the volts were positive or negative.
 
Last edited:

niggle

Pedelecer
Feb 2, 2017
60
14
60
Cornwall, near England
I'm in a similar situation with my Cyclotricity front hub kit, which came with a PAS for the left hand crank, the 12 magnet ring could not be fitted on my square taper BB due to lack of clearance between crank and BB shell, only 2-3mm, so I tried bolting the disc on the triple chainset in place of the granny ring but bizarrely the red LED would only flash if the pedals were rotated backwards, and flipping the magnet disc over made no difference to this. The pick-up sensor is the type you ziptie to the frame and I am guessing it is direction sensitive, I have fitted the magnet inboard of the left crank arm by hacking out a bigger hole in the middle and ziptied it in place, which works but is not very secure and frequently goes out of line. I don't want to fit a longer BB, it would throw the chainline out and increase the Q factor too much for my liking, so I would rather have the magnet ring in the granny ring position but cannot figure out/find a PAS kit that will allow this, function correctly on the right hand side and have the correct round plug (julet?).
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,985
Basildon
I'm in a similar situation with my Cyclotricity front hub kit, which came with a PAS for the left hand crank, the 12 magnet ring could not be fitted on my square taper BB due to lack of clearance between crank and BB shell, only 2-3mm, so I tried bolting the disc on the triple chainset in place of the granny ring but bizarrely the red LED would only flash if the pedals were rotated backwards, and flipping the magnet disc over made no difference to this. The pick-up sensor is the type you ziptie to the frame and I am guessing it is direction sensitive, I have fitted the magnet inboard of the left crank arm by hacking out a bigger hole in the middle and ziptied it in place, which works but is not very secure and frequently goes out of line. I don't want to fit a longer BB, it would throw the chainline out and increase the Q factor too much for my liking, so I would rather have the magnet ring in the granny ring position but cannot figure out/find a PAS kit that will allow this, function correctly on the right hand side and have the correct round plug (julet?).
Any 5, 8 or 10 magnet PAS will work. They're all ambidextrous. It's only those 12 magnet Cyclotricity type that are handed.
 
  • Like
Reactions: niggle

niggle

Pedelecer
Feb 2, 2017
60
14
60
Cornwall, near England
Any 5, 8 or 10 magnet PAS will work. They're all ambidextrous. It's only those 12 magnet Cyclotricity type that are handed.
Thanks. BTW by your user name I presume you have or previously owned a VFR400? If so very cool bike, fancied one myself 'back in the day' but ended up with a rather less exciting GPZ500.
 

FoolThrottle

Finding my (electric) wheels
Sep 17, 2019
11
0
I'm in a similar situation with my Cyclotricity front hub kit, which came with a PAS for the left hand crank, the 12 magnet ring could not be fitted on my square taper BB due to lack of clearance between crank and BB shell, only 2-3mm, so I tried bolting the disc on the triple chainset in place of the granny ring but bizarrely the red LED would only flash if the pedals were rotated backwards, and flipping the magnet disc over made no difference to this. The pick-up sensor is the type you ziptie to the frame and I am guessing it is direction sensitive, I have fitted the magnet inboard of the left crank arm by hacking out a bigger hole in the middle and ziptied it in place, which works but is not very secure and frequently goes out of line. I don't want to fit a longer BB, it would throw the chainline out and increase the Q factor too much for my liking, so I would rather have the magnet ring in the granny ring position but cannot figure out/find a PAS kit that will allow this, function correctly on the right hand side and have the correct round plug (julet?).
I have been too busy to have another go but whatever I tried I couldn't get 5V and a solid red light.

If it is flashing when pedalling backwards then I would try turning the sensor round so that it picks up from the other side of the sensor first? (e.g. turn it upside down if possible).
 

niggle

Pedelecer
Feb 2, 2017
60
14
60
Cornwall, near England
I have been too busy to have another go but whatever I tried I couldn't get 5V and a solid red light.

If it is flashing when pedalling backwards then I would try turning the sensor round so that it picks up from the other side of the sensor first? (e.g. turn it upside down if possible).
No room to fit it upside down, but yes, as I was typing earlier I was wondering whether it would fit inside out, will look at that later.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,785
The European Union
I'm in a similar situation with my Cyclotricity front hub kit, which came with a PAS for the left hand crank, the 12 magnet ring could not be fitted on my square taper BB due to lack of clearance between crank and BB shell, only 2-3mm, so I tried bolting the disc on the triple chainset in place of the granny ring but bizarrely the red LED would only flash if the pedals were rotated backwards, and flipping the magnet disc over made no difference to this. The pick-up sensor is the type you ziptie to the frame and I am guessing it is direction sensitive, I have fitted the magnet inboard of the left crank arm by hacking out a bigger hole in the middle and ziptied it in place, which works but is not very secure and frequently goes out of line. I don't want to fit a longer BB, it would throw the chainline out and increase the Q factor too much for my liking, so I would rather have the magnet ring in the granny ring position but cannot figure out/find a PAS kit that will allow this, function correctly on the right hand side and have the correct round plug (julet?).
I discovered like you that the KT12L is really handed. You can get it to work upside down and disk flipped over but it is a pain in the rear to mount that way.

What I have done is transform an idler pulley on the trike by drilling holes in it an inserting magnets. Yes it is on the right hand side but it turns anti clockwise. Saves me about 1.5 meters of wiring. Photos to follow.