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Topic: RPM/rev counter (Read 3675 times) previous topic - next topic


Hello everybody, I don't know it this is the right place, but here it goes, I would like to make a simple rpm meter for my motorcycle, but I don't really know how to do it, is there anyone that have some links about it so I could grab some ideas to make something that could work?
Thanks in advance  ;)


a bunch of people have done things like that.  If you search for 'motorcycle' in the box above you'll fing some samples.  

does your bike have a tach. hookup point?


I will search about it, no it doesn't have a "proper" signal to read, only have access to the pickup signal, so making an input circuitry will be another challenge, but if it isn't difficult it ain't fun  :D


basic nutshell

you attach a small interrupter to the wheel (lets be proper, it is a motorcycle, maybe a magnet system, maybe optical disk) and a sensor to a stationary place

pipe the rough signal up, make it safe, clean it, and then read it

How you go about it depends on a ton of different variables, starting with what are you attaching it to, ie a 50cc scooter, or a 1500cc turbo crotchrocket?


The pickup is a magnetic sensor used by the cdi to sense the position of the crank and uses that information to make the ignition spark in the exact time/moment, I just want to buffer this signal and clean it up to connect it to the arduino.
The bike will be an 125cc 2 stroke, or some 50cc to 100cc 2 stroke racing engines, I think I already have some good code to do this, tomorrow I will post it here and I will test it next week in my university labs.
Attaching one hall sensor and a magnet to one wheel would make a very nice speedometer.


I made a RPM/speedometer attached to my bicycle. I used a reed switch and 2x7 segment display. After some difficulties with interrupts it finally worked. I based my code on a code I found on the Playground and showed the rpm of a computer fan. I changed that and added the display code, voila !

It should´t be to difficult to hook up a simillar system like mine but in stead of reed switch use the spark signal. There are also some kits you could buy, I remember one from a Greek company but I can´t remember the name  ::)

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