0-60/100 mph timer electronics project

[GuyMelvin]

As an apprentice engineer i have an electronics project that has to be something to do with something automotive.

I have chose to do a 0-60 / 0-100mph timer. I have not thought about the circuit properly yet, but i know roughly what i have in mind.

The way i am going to have it operate is by picking up from the speedo (may not be a micra, may not be a car, may use a signal generator to replicate the pulse) when the first pulse is sent to the speedo (when the car starts moving) the timer will start, when the pulse reaches a certain frequency (the frequency @ 60/100mph) the timer will stop.

What i need to know is what the frequency of pulses the speedo recieves at the given speeds? Does anyone know this or know how to work it out?

Many thanks

 

[GuyMelvin]

I guess no one can help? :doh:

 

[frank]

I guess no one can help? :doh:

your best bet would be to measure the pulses guy surely ? electronic speed displays on the roadside ?
very diff ratio/tyresize Dependant tho eh

 

[GuyMelvin]

how could i measure the pulses without an oscilloscope? :down:

 

[superls]

my k10 and an old primera is 1063 ish (iirc) rpm (pulses per minute) at 60MPH

if you take your instrument cluster to pieces it tells you the calibrated rpm/speed on the mechanism and dial.

note they were the cable driven clocks.