speed meter for bicycle

[aspirecole]

what is the common way to build a speed meter for bicycle?

 

[spudboy488]

A simple way is to put an interrupter of some kind on a wheel so you can count revolutions. Measure and calculate the radius of the wheel so you know how far you've traveled for each revolution. Count how many times the wheel turns for a given time period. Use your math skills with the the values you have (revolutions*radius divided by time) to calculate speed in whatever units you want.

How you build it is up to you. Commercial speed units (I believe) have a magnet that bolts to a spoke on the wheel and a sensor on the fork that is used to count. You set the wheel size in the receiving unit and it calculates the speed and distance.

 

[aspirecole]

How you build it is up to you. Commercial speed units (I believe) have a magnet that bolts to a spoke on the wheel and a sensor on the fork that is used to count. You set the wheel size in the receiving unit and it calculates the speed and distance.[/QUOTE]

is it possible to make it with reed switch..can u help me with the code..im using arduino uno

 

[spudboy488]

A reed switch will probably work. I'm a PIC guy so you'll have to find code help elsewhere.

 

[aspirecole]

A reed switch will probably work. I'm a PIC guy so you'll have to find code help elsewhere.

compare IR, reed switch and hall effect sensor..which one is the most reliable or efficient

 

[betwixt]

If you use IR you need a light emitter (IR LED for example) which will draw power all the time and quickly drain a battery. The magnet and reed switch suffer the problem that they have to be in very close proximity and if you go fast, the magnet may pass the reed too quickly for it to operate. A magnet and Hall effect sensor will work or another method is to use a magnet and pick-up coil so it produces an electrical pulse as the magnet passes by. Try looking up "reluctance sensor" for more information.

Brian.

 

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