I would like to build a Panel mount Tachometer for my auto garage.Once the engine come from the service station i wanted to check th e rpm of the same.instead of using readymade handheld tachos ,i would like to build my own digital panel mount one.Sensor unit should be seperate and display unit should be seperate.

Would any have the idea to do this.if so pls help me in this regard.

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Dr.Edison

 

Look here, you might have to order the magazine

http://216.239.63.104/search?q=cache...al+tacho&hl=en

or kit

http://www.quasarelectronics.com/1143.htm

If you want to build it yourself you will need something like a PLL to multiply the input from the pickoff to display RPM on a digital counter circuit. The loop constant will have to be fairly long to smooth out the variations in idling speed. You will also need a switch to select various divide by N settings to cater for 4, 6 or 8 cyl engines. This part could be performed by a PIC micro or similar small micro.