Push Bike Speedometer

[Killerkroz]

Hi I was wondering if any1 could help me.

i need a nice easy Circuit for measuring the speed of a push bike.

i have the general idea on how it would work but dont have a circuit

any help would be great

Thanl you.



Dave

 

[stevez]

What is a push bike?

For bicycles they do make/sell speedometers that use a magnetic sensor that is fixed to the frame along with a magnet that is attached to one of the wheels. The sensor send a pulse each time the magnet passes indicating one turn of the wheel. By knowing the circumference of the wheel and the counts per unit time the speed can be calculated. A small computer provides the calculations and dispays the output. Nashbar, among others, sell them. I am sure plenty of people have made their own. A PIC or some other small microcontroller can probably handle this task.

 

[Killerkroz]

Thanks stevez but i was looking for more of a circuit
i plan to use a frequancy to voltage converter and a bank of comparators
so with the out put of the frequancy converter chip the comparators hopfuly will light up the led's any help on how to achive this would be great


Thank you

 

[hyedenny]

Hi,
The datasheet for the LM2907 or LM2917 shows exactly what youre looking for. Use this with a LM3914 and you'll have your bargraph display. I have a circuit if you still have trouble.

https://www.electro-tech-online.com/custompdfs/2006/03/LM2907.pdf
https://www.electro-tech-online.com/custompdfs/2006/03/LM3914.pdf