Interfacing a Analog Speedometer with Arduino

Projects General Guidance
1

I have a Primitive bike , i wanted to connect the Analogue Speedometer inputs to the Arduino and show the speed over a LCD , Is there a mechanism with which i can do this?

This Analogue Speedometer runs with a wire joint with the wheel's Drum brake! and it is like a REED SWITCH

IT WORKS LIKE:
When the car or motorcycle is in motion, a speedometer gear assembly will turn a speedometer cable which then turns the speedometer mechanism itself. A small permanent magnet affixed to the speedometer cable interacts with a small aluminum cup (called a speedcup) attached to the shaft of the pointer on the analogue speedometer instrument. As the magnet rotates near the cup, the changing magnetic field produces eddy currents in the cup, which themselves produce another magnetic field. The effect is that the magnet exerts a torque on the cup, "dragging" it, and thus the speedometer pointer, in the direction of its rotation with no mechanical connection between them.

2

You already have a rotating magnet, just place a hall effect sensor near it and read the pulses.

BTW thanks for describing those old speedos, I knew what they did but not how.

Rob

3

Thanks Gray Nomad, Im the same guy from india who contacted you on personal Email regarding automatic water tank filler system, I'm also there on facebook with you and have seen your Marvelous Truck where you live in.

Anyways.....
WHat do you mean by near the magnet?
Do you mean anywhere near it? or something else?

Regards and Respect,
Nishant

4

If you have something rotating, you might attach the DC motor from something like a 2 AA battery motor toy and have it act as a generator. Then you could measure the output voltage.

5

Hi Zoomkat Thanks but i want to implement some professional system like the bike manufacturers use because i need to make it for a modifying bike, knowing that the accelerometer reacts to weight , Does it have some utilisation here?

6

Nishant:
Thanks Gray Nomad, Im the same guy from india who contacted you on personal Email regarding automatic water tank filler system, I'm also there on facebook with you and have seen your Marvelous Truck where you live in.

Anyways.....
WHat do you mean by near the magnet?
Do you mean anywhere near it? or something else?

Regards and Respect,
Nishant

Place the Hall sensor so that the north and south poles of the magnet comes close to it alternately as the magnet rotates.

7

Hi Nishant,

Did you ever figure out that water system? I was later thinking that all you need is a float valve.

WHat do you mean by near the magnet?

Usually a few mm so when the magnet passes it activates the sensor.

Rob

8

Hi, im trying to figure out the oposit, i have the mesure from my e bike controller so I know the speed Im driveing, but want to add a nice Analog speedometer that works for motorcycles. I cant figure out how to interface my arduino to make it work..

9

Please open a new thread for this unrelated subject instead of resurrecting a 7 year old one.

And when you do, also add a detailed description of the input your analog speedometer requires. Without knowing this, there's just no way to build an interface.