Any body has any idea about making a Digital Speedometer. I want to use that thing into my motorcycle.

-Mahesh Joshi
Bhopal, India

 

A speedometer (or tachometer) is just a frequency measuring device, you first need to get a signal from the bike representing your speed. From that you can generate any display you want, even a 555 timer can be used to generate an analogue voltage from it, then feed LM3914's to give a nice analogue LED display. Or you could measure the frequency using a micro-controller, and display it on LCD's, LED's - pretty well anything you want.

 

Thanks Nigel

but can you give me some more idea about it, circuit diagram etc.

-Mahesh Joshi
Bhopal, India

 

We need to know what sort of signal you have got, and what sort of display you want.

 

I can think of one way to do this but it may be hard. use the spark from your engine (somehow there is a way but i forget) to create a rpm counter and some how find a way to electrontaly determine the gear you in and you can use electrontics to caculate the speed.

 

on bicacles you can buy a spedometer that works by puting a magnet on you spokes and another thing on your forks and it counts the rpms of the wheel and multiplys that by the radias. and converts that # into a mph don't know how to do it i am just offering ideas

 

Yes andrew, I am talking about the similar one which is used in bicycles. I have an another idea. A wire (chain) comes to the analog speedometer from the front wheel which is connected to a gear mechanism there. The wire rotates and the meter moves the niddle. Is there some method to conver those rotations to digital form so that we can display the numbers digitally.

-Mahesh Joshi
Bhopal, India

 

ok I am new to electrontics so i will not be able to make you a diagram but i am just offering ideas and may be some one else can help you on that. but i did get a idea, a read somewere that you can use a electric motor as a generator so what if you were to attach a motor to the spinning shaft and make a electrical circuit to tell how fast you are going buy the voltage the small motor is putting out ( only and idea don't know for sure that it will work.) or what if you put a magnet into the sprocket of the rear wheel and use that magnetic theroy. one thing to renember is, that it is alot harder for a newbe to make it then it is to buy one :lol:

 

Food for thought...

For many years now, electronic speedometers and tachometers have been used in many types of highway vehicles. My experience has been with heavy-duty trucks, so I'll explain the signal generators (pickup mechanisms) used therein.

The most-commonly used pickup is basically a coil of wire wrapped around a permanent magnet in "rod" form. This in then ecased in a housing that allows for convenient mounting within proper proximity to its triggering device. In most cases, the tachometers used the engine flywheel (starter) teeth for triggering, and the speedometers used a toothed reluctor wheel that was mounted to the transmission output shaft in place of the traditional speedometer drive gear.

The operation of the sensor is simple -- the approaching and departing teeth on the trigger wheel would cause a signal with a sine wave form to be generated in the sensor's pickup coil. The frequency of the generated signal is dependent upon the rotational speed of the trigger wheel.

There are many aftermarket signal generators available. Take a look here for the offereings of just one company... many different drive methods are available, including types intended to be driven by the factory drive cable already installed.