need some help for my tachometer project
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Joined: Dec 2005
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need some help for my tachometer project
Hi there
OK, here is the story:
I'm building low cost tachometer which should be as digital as analog type. For pointer driving I will use a small servo which is controlled by PWM. Central point of circuit is PIC MCU. The MCU should produce PWM for servo and monitor pulses from distributor giving right PWM siglan/pause relation.
But things are not so simple.
Here is what I know:
100RPM=200puls/min, which is 200/60=3.33 pulses in one sec.
Signal from distributor is sqare type, amplitude is about 12V and when iddle signal pause relation is 35:5 msec where 35msec is 12v signal and 5 msec is logical zero pause.
Does anybody knows signal/pause relations as RPM increase?
The car is CRX, but if I build my tacho it could be applied on any car.
There's some examles with ne555, but I would like to do it with PIC because it could monitor a ot of things, not just RPM, than speed or coolant temp....
regards..
OK, here is the story:
I'm building low cost tachometer which should be as digital as analog type. For pointer driving I will use a small servo which is controlled by PWM. Central point of circuit is PIC MCU. The MCU should produce PWM for servo and monitor pulses from distributor giving right PWM siglan/pause relation.
But things are not so simple.
Here is what I know:
100RPM=200puls/min, which is 200/60=3.33 pulses in one sec.
Signal from distributor is sqare type, amplitude is about 12V and when iddle signal pause relation is 35:5 msec where 35msec is 12v signal and 5 msec is logical zero pause.
Does anybody knows signal/pause relations as RPM increase?
The car is CRX, but if I build my tacho it could be applied on any car.
There's some examles with ne555, but I would like to do it with PIC because it could monitor a ot of things, not just RPM, than speed or coolant temp....
regards..
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