crank arm magnet for Tacx cadence sensor

Tacx are wonderfully unhelpful with either the user manual or a lost cadence magnet for a Tacx Flow trainer
“T220017” that I just inherited.
I am trying to recover from a disc herniation and the physio suggested a stationary bike. Anythings worth a shot!

But the trainer I’ve been given has neither user manual nor cadence magnet.
I’ll give it a shot without, but wondered if you helpful lot have any ideas please. Is it just a normal magnet that’s used for these purposes? Crankarm mounted cadence magnets?
Can I use any old small magnet?
Here’s a pic of what I think the part looks like.

https://www.wiggle.co.uk/tacx-cadence-magnet

Thanks lots.
Neil

I THINK I discovered that a Neodymium Disc Magnet (12mm dia 2mm thick) will attach itself nicely to the end of the pedal axle and work with my sensor, lets see, its on it’s way

Yes that will work fine they are the correct type, you might have to stack 2 of them though.

you can easily get thicker ones, I have one that fits the back of the axle inside the recess from the crank / pedal hole, so it can’t get knocked off but sits prouder / nearer to the sensor.

Thanks for the tips
The Neodymium Disc Magnet (12mm dia 2mm thick) for ebay works great.
I just placed one on the inner end of the pedal spindle and as that’s steel it stuck itself on.
Seems to work fine with the cadence sensor.
The rest of the 10 pack I bought are great for sticking stuff into the fridge.

I use the same magnets on both road bikes – just placed on end of pedal axel. They are more than strong enough that you won’t need more than one, as they will trigger the sensor. If your pedal axel is slightly proud of the crank, then a blob of superglue stops the magnet moving (it won’t fall off). If the axel is slightly recessed, you won’t need any glue.

Yep.
Ebay magnets.
See above.
Great solution.