Digital Speedometer

[mahesh_jo]

Does any one has any idea about making a digital speedometer?
I want to develop this for my motherbike. Can we use the existing machinism (chain driven from front wheel) to convert the rotating chain count into ditigal display kmph.

-Mahesh Joshi

 

[vaineo]

I had one on my bike that used a magnet attached to the wheel and a sensor that was mounted off the wheel at the same height.

 

[absolution]

i used to have an old meter like that for my bike. it was a sensor setup by the wheel with a unit attacked to the wheel im guessing a magnet. to try something similar, try some sort of magnetic sensor possibly like that which people use for home security and run it through a frequency counter or a frequency to voltage convertor and run to a voltmeter. of course you'd have to do the calibrations yourself. i say scratch this idea and just go buy one they arent that expensive.

 

[jbeng]

i say scratch this idea and just go buy one

Sometimes, people get more satisfaction in doing things themselves, instead of just throwing money at a problem...

Here's the link to a thread which was discussing magnetic pickups:https://www.electro-tech-online.com/threads/how-to-measure-current-in-pic-pic-as-an-ammeter.10097/
In that thread, I showed a photo of a pickup that I made using the coil from an old relay which can be used to sense the teeth on a rotating gear or a chain running past it. This will give a signal directly proportional the speed. Condition the signal from the pickup to get a squared waveform, then send the signal into your counting and display circuitry.
JB