Hi, I am now sitting bike computer project. I read a lot about bike computers from internet. Now some topics cleared and some topics confused. The problem is how to calculate the speed of the vehicle ?. Hall sensor is mounted at shake absorber.(front fork). magnet is mounted alloy wheel. Hall s…

Speed is distance divided by time. Distance is the circumference of the wheel. Time is the interval between sensor triggers.

Speed is distance divided by time. Distance is the circumference of the wheel. Time is the interval between sensor triggers. Ok. Distance is the circumference of the wheel. I think I done below you said. Now my bike radius is 27" inch. (Hall is triggered by magnet once per rotation) r=27 P…

By recording the time of each trigger, and subtracting.

Ok. Using timer0 and external interrupt is enough for this ?.

SureshKumar2610: Ok. Using timer0 and external interrupt is enough for this ?. It's too much for this. An ISR is a good idea, because even though the time between pulses is long, the pulses are short. But all you need to do to get the time is capture the value of millis() in the ISR.

I suggested this code in another recent Thread. It compiles but I have not tested it byte pulsePin = 2; unsigned long prevPrintMillis; unsigned long printIntervalMillis = 1000; unsigned long prevPulseMicros; unsigned long newPulseMicros; volatile unsigned long latestPulseMicros; volatile boolean n…

Ok. thanks I try this and update to you all.

SureshKumar2610: PI=3.1415926535897932384626433832795 How accurately do you need to know your speed? Because this amount of digits is useful for measuring the radius of an atom in lightyears.

MorganS: How accurately do you need to know your speed? Because this amount of digits is useful for measuring the radius of an atom in lightyears. HAHAHAHH That did make me LOL When I read the OP code, I thought - don't do the floating point math on the arduino! If the circumference is 170", u…

MorganS: How accurately do you need to know your speed? Because this amount of digits is useful for measuring the radius of an atom in lightyears. Also, PI is already defined in Arduino.h

How to make Bike Speedo Meter.

Projects General Guidance

allanhurst June 5, 2017, 8:40pm 12

A nice little project.... but you can buy such a device powered by a coin cell for about £6 from any bike shop..

Allan.

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How to make Bike Speedo Meter.

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