Help me with making odometer circuit for a scooter

[david90]

odometer circuits?

I'm trying to make an odometer for my scooter. the scooter is motorized and is pretty small (22 lbs). I'm thinking of a magnetic pickup type sensor and using avr to process the pulses from the sensor.

How do you make the sensor? I know how it work but my knowledge is not too deep.

 

[IanP]

Re: odometer circuits?

For distance/speed measurement you will need only one pick-up device which, in your case, can be a hall sensor or a small reed switch.
You can try to attach a disk to the shaft and glue several small permanent magnets. The more of them you have the better the reading will be..
Other option is based on the same disk, but this time you will drill holes instead of gluing magnets, and as sensor and pick-up device you will be using a LED diode combined with a phototransistor. This component looks like a small bridge with a gap in the middle for inserting disk with drilled holes.
Rest are just calculations of number of pulses per time ..
Regards,
IanP

 

[david90]

odometer circuits?

Is using reed switch reliable? Aren't they mechancial and not solid state?

 

[IanP]

Re: odometer circuits?

Personally I would prefer a hall sensor over reed switch, and, yes, it is mechanical device. However, these switches are very reliable as they don't operate in presence of air (oxygen), so, if you have them - use them.
Regards,
IanP

 

[david90]

odometer circuits?

what kind of pulses do hall sensors output? Do you need to amplify or condition the signal before inputting to the avr?