Hasan said:
I am a final year student of bachelor of Computer Engineering. As my final year project i am required to digitize all the displays present on the dashboard.that include the tachometer the speedometer the fuel and temprature guageand other realted items. Before converting them to digital i must firat know how they work. So can u please explain me their workin. I think that regarding tachometer when we step on the accelerator the current increases and the rpm needle moves . I wana know how the current varies.Also plz tell me how can i covert all these items to digital. Would i be requiring analog to digital converters. I fu have answers to any of my question plz reply and also plz send me if u have some useful links. Ill be refering to u from time to time as my project progresses
Thanking you in anticipation.
A lot depends on the age of the car, older cars used mechanical speedometer and tachometer displays, where a mechanical drive cable rotates a magnet (or a metal plate) inside the meter, the needle is connected to a metal plate (or a magnet) and is moved against a spring depending on the speed of the rotating part.
Your biggest problem is probably getting an electrical signal from the mechanical rotation. Car computers have been popular addons over the years, you can possibly still buy interface components?.
More modern cars may well just generate a pulse from the engine (tachometer) and gearbox (speedometer) and process them electronically. A common way of adding a tachometer is to pickup the ignition pulses, in older days coming from the points, now coupling off the input to the distributor.
The other instruments will probably be fairly easy to do, they are just crude meters fed from various transducers.