Magnet relocate for smart trainer

Hi all,

 

I need to get a magnet relocation going, to a point higher up and further away. Essentially so I can use a smart trainer with e-bike power. The spinning disc is a good 80mm away and about 50mm up. System is tq trek domane.

 

I see two options,

1. Build a relay like this, https://www.pedelecs.co.uk/forum/threads/ebike-derestrictor.25266/

but to be honest I don’t understand the coding part.

2. Buy a badass box and try to cut it up so the sensor (presumably a hall sensor) is further away on the circuit. But this looks tricky given the small circuit board.

 

Any other ideas or suggestions please?

 

Thanks in advance

 

KP

Hi all,

 

I need to get a magnet relocation going, to a point higher up and further away. Essentially so I can use a smart trainer with e-bike power. The spinning disc is a good 80mm away and about 50mm up. System is tq trek domane.

 

I see two options,

1. Build a relay like this, https://www.pedelecs.co.uk/forum/threads/ebike-derestrictor.25266/

but to be honest I don’t understand the coding part.

2. Buy a badass box and try to cut it up so the sensor (presumably a hall sensor) is further away on the circuit. But this looks tricky given the small circuit board.

 

Any other ideas or suggestions please?

 

Thanks in advance

 

KP

Pictures and maybe a bit more clarity on what you are trying to do would help.

Hi all,

 

I need to get a magnet relocation going, to a point higher up and further away. Essentially so I can use a smart trainer with e-bike power. The spinning disc is a good 80mm away and about 50mm up. System is tq trek domane.

 

I see two options,

1. Build a relay like this, https://www.pedelecs.co.uk/forum/threads/ebike-derestrictor.25266/

but to be honest I don’t understand the coding part.

2. Buy a badass box and try to cut it up so the sensor (presumably a hall sensor) is further away on the circuit. But this looks tricky given the small circuit board.

 

Any other ideas or suggestions please?

 

Thanks in advance

 

KP

I made a remote trainer. It's brilliant. I bolted my ebike to my turbo trainer, like normal, then put a rubber band on the throttle to hold it open. It can run for about an hour before the battery goes flat, so I can get fit while I watch TV in the armchair without getting sweaty.

 

Really, though. I don't think anybody has a clue what you have or what you're trying to do. It might be an idea to start at the beginning.

Edited December 29, 20241 yr by saneagle

Sure thing.

 

Picture of bike sensor: in red box is the area where the magnet passes and registers for speed.

 

Picture of trainer: purple cross shows where the magnet should be, but there’s nothing rotating I can use so that’s a no go.

The Red Cross shows where I could attach a magnet, but current sensor on bike won’t pick it up, too high and too far away. So I need something to read the signal from the Red Cross, and relay it to the sensor which is nearer the purple cross!

 

No idea what you are on about.

Think? op wants to use an ebike and the already fitted pas/speed? sensor magnet to trigger the trainer sensor?

 

why not just add a 2nd magnet with a drop of superglue? or blu-tak if you prefer a temporary only when training measure?

Think? op wants to use an ebike and the already fitted pas/speed? sensor magnet to trigger the trainer sensor?

 

why not just add a 2nd magnet with a drop of superglue? or blu-tak if you prefer a temporary only when training measure?

Thank you. Yes, I have an e-bike already, but it needs a magnet sensor to activate, and if I remove the rear wheel it doesn’t have a magnet to activate!

 

the 2nd magnet with superglue idea, my problem is it’s just too far away to activate. I need to bridge that gap somehow.

? Still no wiser? perhaps if you post pics with a wider view of both bike and trainer? name/ id the bike and trainer too and provide links to specs if possible.

 

Generally magnets on wheels tend to feed speed sensors which will come into play on a rd legal bike at 15.5mph to cut off any motor assistance. While cadence and torque sensors required by regs to trigger motor assistance can usually be found on or close to the bottom bracket.

 

But your tight shots suggest your bike might be a bit whacky??

 

 

 

Perhaps, if i understand??? the cheapest way to hack a simple reed switch sensor to anything is to ebay/aliexpress one of the cheapest cycle 'computers' on the market circa $1-2? it will come with a magnet to attach to a spoke and a simple 2 wire sensor attached that you can cut off and wire into any similar sensor input. its a 2 wire Normally open sensor (**dont take my word- test with a meter and magnet!) that will close when within a magnetic field strong enough (not a magnet expert) to wire upto a 3 wire connation just use the sensor input and ground only.

I don't know much about electrickery, but perhaps the magnet on your crank arm could activate a strong electromagnet at the rear of your bike, via relay via a sensitive hall switch situated close to the crank arm magnet on the bike frame? Or wouldn't that work?

 

https://theelectronicgoldmine.com/en-gb/products/g27080

 

Or to bridge a gap?? use tape and thick cardboard to stand the magnet off further.. the foam sheets used in packing make fine padding/spacers.. or use a stack of magnets, what size gap needs bridging? 5x 4mm thick magnets would bridge 2cm..

 

a hot glue stand off?? a drop of isopropanol post extercise would remove it for later application with velcro perhaps?

 

still cant picture the issue?? - but its buggin me..

A photo, make and model of the smart trainer would help. I can make out the word "Crapk" or "Crank", I think.

 

This one?

 

https://www.sigmasports.com/item/Wahoo/KICKR-CORE-Smart-Turbo-Trainer/J8SP

 

 

https://www.balfesbikes.co.uk/accessories/turbo-trainers/wahoo-kickr-core-smart-turbo-trainer__18971

 

Ok this might have been worded badly given your responses, so I’m sorry for that!

 

Let me ask this way, imagine a speed sensor on a basic cycling computer, it needs a magnet passing it to register speed.

 

However, that magnet is too far away.

 

I can’t move the sensor, and I can’t move the magnet either. So I need to bridge the gap. That’s basically what I need!

 

For actual info:

The sensor is the e-bike speed sensor. I cant move it as no spare flex in cable.

The magnet is far away, as it’s on the kickr trainer (yes, that link posted is the one)

I could re-wire the sensor, but I’d rather recreate a signal of a magnet passing it.

https://www.first4magnets.com/circular-disc-rod-c34/15mm-dia-x-2mm-thick-n35-neodymium-magnet-1-8kg-pull-p6221#ps_0_6416|ps_1_6746

 

just glue them together as worked on old bike where the sensor was to far away on front fork to pick up the speed

https://www.first4magnets.com/circular-disc-rod-c34/15mm-dia-x-2mm-thick-n35-neodymium-magnet-1-8kg-pull-p6221#ps_0_6416|ps_1_6746

 

just glue them together as worked on old bike where the sensor was to far away on front fork to pick up the speed

 

Unfortunately, there is a big arm in the way for part of the rotation, so I can’t extend the magnet like that. Needs to become electrical not mechanical.

Unfortunately, there is a big arm in the way for part of the rotation, so I can’t extend the magnet like that. Needs to become electrical not mechanical.

https://www.youtube.com/watch?v=xVEj36ABsVU

https://www.youtube.com/watch?v=PLuldZbteoQ:1106

I'm curious to know why you're trying to do this. Don't all trainers like these have Bluetooth and/or ANT+ built in to transmit speed, power, cadence etc that link to Apps - even non-subscription/free/generic ones? Even my particularly crap Halfords-bought one has that basic functionality. A trainer would be a pretty useless device unless it can tell you at least those basic stats.

 

What is it you're trying to achieve?

How does it work if you use a non-ebike, and why does it need to be different?

 

Are you using an ebike to produce impressive data from the trainer?

 

If not, does the extra mileage that will be registered by the ebike not matter?

How does it work if you use a non-ebike

 

https://support.wahoofitness.com/hc/en-us/articles/115000296704-KICKR-Smart-Trainer-Information-and-Setup

then move the sensor or spend a £ or so on an additional one as suggested above. It would help if you stopped being so cagey about what you want to do.. i doubt anyone will give a toss if your trying to 'Donald Trump' the online trainer rankings, few in here are lycra sympathetic ..