I don't understand how a single-hall sensor can tell the difference between the two directions. Do you know? I'm interested...
Alternatives to flipping PAS disc?
- Thread starter Yak
- Start date
The magnetic field is directional. The magnet has to pass in the correct direction to switch on the hall. It's like a sprung-loaded tap. It onlty switches on the water if you turn it in the right direction. When you let go, it would spring back and switches the water back off. If you turned the tap the other way, nothing would happen.
Fleming's left-hand rule - Uses of magnetism - Higher - OCR Gateway - GCSE Physics (Single Science) Revision - OCR Gateway - BBC Bitesize
Learn about and revise electromagnetism, the motor effect and its applications in motors and loudspeakers with GCSE Bitesize Physics.
www.bbc.co.uk
Thanks... so does a single hall sensor "look" for "no field" as well as North-changing-to-South? Because N-S-N-S-N-S looks the same as S-N-S-N-S-N once it's started. Whereas N-S-x-N-S-x is different to S-N-x-S-N-x if the "no field x" can be arranged to happen like that. Is that the way it works?The magnetic field is directional. The magnet has to pass in the correct direction to switch on the hall. It's like a sprung-loaded tap. It onlty switches on the water if you turn it in the right direction. When you let go, it would spring back and switches the water back off. If you turned the tap the other way, nothing would happen.
Fleming's left-hand rule - Uses of magnetism - Higher - OCR Gateway - GCSE Physics (Single Science) Revision - OCR Gateway - BBC Bitesize
Learn about and revise electromagnetism, the motor effect and its applications in motors and loudspeakers with GCSE Bitesize Physics.www.bbc.co.uk
A suggestion for the Yose sensor you have - that might help you work out a solution.
Remove the cableties so the sensor isn't fixed to the bike, hold the sensor so it's in line with the frame downtube, slightly above/below is ok if you need clearance.
You want the end with red led and cable as near the crank as you can get it, and the "magic" end of the sensor with "+" mark lined up with the magnets on the disk. It won't sit at true 90* but it's near enough. Holding my Yose sensor like this fixed my "reverse" problem but my oversized frame tubes didn't leave space to mount the sensor permanently.
Remove the cableties so the sensor isn't fixed to the bike, hold the sensor so it's in line with the frame downtube, slightly above/below is ok if you need clearance.
You want the end with red led and cable as near the crank as you can get it, and the "magic" end of the sensor with "+" mark lined up with the magnets on the disk. It won't sit at true 90* but it's near enough. Holding my Yose sensor like this fixed my "reverse" problem but my oversized frame tubes didn't leave space to mount the sensor permanently.
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I tried this first, but couldn’t invert the sensor much past 90 degrees, let alone 180, and still get the magic end to line up with the ring of magnets. The motor came on, but cycled on/off - and the same when pedalling backwards.
l’m thinking now about prising out the magnets and sticking them directly to the smallest chainring to enable me to invert the sensor almost fully as the ring of magnets would be much larger...and with 12 magnets I hopefully will still get the motor to come on quickly enough if starting uphill...
Extra question - I now have a new PAS sensor that mounts horizontally on a metal ring. I’ve reversed it, I’ve temporarily wired it up (scary, thanks Nealh for previous wIring match-up post) and IT WORKS! BUT! It works pedalling forwards and backwards - is this normal for this type of sensor? I’m ecstatic it works at all, but I can see myself returning the pedal to the top of the stroke ready for the off at a set of lights and boosh! I’m in the middle of the junction. Is this fixable - or do I just learn to live with it?
It works with a 12 magnet ring, like the old one, so I’m hoping there won’t be display resetting to do. The blurb also says it is:
DUAL-MAGNETIC: Employs the double magnetic loop, the elastic Hall angle difference to detect the dynamic torque, which is converted to DC signal and sent to the controller.
...which may mean something?
It works with a 12 magnet ring, like the old one, so I’m hoping there won’t be display resetting to do. The blurb also says it is:
DUAL-MAGNETIC: Employs the double magnetic loop, the elastic Hall angle difference to detect the dynamic torque, which is converted to DC signal and sent to the controller....which may mean something?
if your pedal sensor works both ways, your controller is programmed to expect a Dual Hall pedal sensor.
The sensor head is usually coloured black, not red. Like this one:
The sensor is 'intelligent', it won't fire when you pedal backward.
The sensor head is usually coloured black, not red. Like this one:
The sensor is 'intelligent', it won't fire when you pedal backward.
Thank you for replying Woosh - I guess that’s what the ‘dual magnetic’ blurb is that was in the advert for the new sensor? But if my original sensor (nifty thing with an led, pic further up thread) was dual, and the new sensor (black, like your pic) is dual, shouldn’t things go one way only?
Also, do you have any more brackets like your pic? Mine has a tiny offset, and the disc maybe touches it. Yours has a bigger offset, and I don’t want to try bending such a flimsy bit of metal with my paws!
Also, do you have any more brackets like your pic? Mine has a tiny offset, and the disc maybe touches it. Yours has a bigger offset, and I don’t want to try bending such a flimsy bit of metal with my paws!
With the simple red sensor, you have 50% chance to get it right first time.
With the King Meter Dual Hall sensor, you don't have to worry about which way you install the magnet disc. The DH sensor automatically recognise the forward direction, just like the left side pedal sensor, easier if not foolproof installation.
It’s one of these, with the description I mentioned above, allegedly made by ‘VGBEY’...I just took it for a spin, had to adjust that ’number of magnets’ setting people on here have struggled with that screws the speedo reading, and it def works pedalling fwd and bwd
this one should work:
King Meter Pedelec Speed Sensor Set of 2 12 Magnet for Crank Installation on the right side : Amazon.co.uk: Sports & Outdoors
Shop King Meter Pedelec Speed Sensor Set of 2 12 Magnet for Crank Installation on the right side. Free delivery and returns on all eligible orders.
www.amazon.co.uk
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