Generate magnetic field to trigger speed sensor of e-bike

I have an e-bike that I want to speed up a little bit. The idea I have is the following. I have an Arduine One board with Hall sensor that measures the speed of the rear wheel of the bike. The output is something that generates an magnetic puls that will be used to fool the original sensor of the ebike.

This must be low current otherwise the connected AAA batteries for power supply will run empty very fast.

So I guess the question is How can a generate a magnetic field that is strong enough to trigger the speed sensor of my e-bike. I think the strength of the magnetic field should in the range of what is needed to trigger a 44e 402 hall sensor.

An suggestion how to tackle this problem?

I'm pretty sure that nothing you can do is going to make it go faster because the speed is a function of your accelerator , which if on full is the maximum speed, meaning the maximum torque capable and you can fool it all you want but unless you change the magnetic properties of the motor itself , it probably is not going to go any faster. Why would the bike be designed to go slower than it is capable of ?

If your trying to get past a speed governor, what access do you have to the current sensor?
How is the current sensor getting it pulse?

Interrupting every other of its signals will make it “think” it’s going 1/2 speed.
So if it’s a sprocket based pulse, you could file down every other tooth.

The only way to fool the existing speed sensor is to replace it with another one that provides a similar pulse output but at a slower rate, but this depends on what is currently limiting the bikes speed.
An easier solution is to simply reprogram the bikes controller with a smaller wheel diameter which will allow it to go faster, but only if the speed limitation is the wheel speed.

Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.,148850.0.html .

How fast does your ebike go now, and how fast does the law allow an ebike to go?

More speed means more load on the control circuit and if the control system allows, more current through your motor.
Are they rated for the extra performance.

Can you tell us your electronics, programming, arduino, hardware experience?

Thanks.. Tom.. :slight_smile:

so you want to chip it like they do on cars ?
if the sensor measures only RPM why dont you generate the electrical pulses at the desired "speed"?
you could put a switch once you want an extra speed you change the source of the pulses... you send your own electrical train of pulses.. replacing the original (but measuring it of course)

Thank you all for your responses.

What I basically want is to make this product:

My experience level with Arduino and Electronics newbie. I have some experience from the past with Microcontroller and writing software for that. What I have currently working is reading the magnetic puls with a Hall sensor connected to my Arduino. The missing part is the generation of the magnetic pulse.

So the sensor of the E-bike is triggered by a magnetic pulse. The cycle supported is limited to 25 km/h above that speed the support stops. This is a legal thing. The engine can do more but is not allowed by law. I want to go al little bit faster 30 km/h

I edited my answer, i didnt write "electrical".
in my opinion you can generate the needed electrical pulses so you can cheat the measurement instead of discovering electromagnetics ... a hall effect is offering something you can imitate with another transistor dont you think ?
but the solution offered by the Germans there is non-invasive I understand. it looks like they are really generating their own pulse after measurement of the speed. and with low energy such as 1 battery for 7000km !. very interesting. requires good investigation fools not at all this guys patented the thing !

Is your ebike a Yamaha, as that device seems to be designed to be used with a specific type of speed sensor?

Thanks for being specific, takes so much guess work out.

So that device tracks the revised magnet on a spoke and transmits a slightly slower electromagnetic pulse of its own which is read by the factory sensor.

Seems like something a attiny, a Hall sensor and a small coil could do.

Maybe try placing a micro reed relay next to your speed sensor and set it up to pulse on and off.

Does your controller have a setup page/control?
If so does it have a wheel diameter selection?

If you tell the controller, the wheel is smaller diameter than it really is, then it will spin the wheel faster to get the programmed top speed.

Tom... :slight_smile:

Thanks again for the replies on my cry for help :wink:

The reed relay solution looks promising to. I hope the casing of the reed relay does not keep the magnetic field inside and is strong enough. Any suggestion of a manufacturer and product?

Further more I don't have access to the controller of the E-bike. So no configuration possible.