Diddy wheel count sensor

Not sure the best place to put this, but here goes...

Has anyone considered adding a wheel rotation sensor to the Diddy's center wheel on each side? I'm thinking a chopper wheel and a photo sensor. But perhaps Hall effect instead?

Would be very useful for measuring relative distance, and thus for mapping out a floor plan in a room.

Thanks!
'sig

I've certainly thought about it, but that's as far as I've got. I'm hoping that, for now, I'll be able to get by with dead reckoning; that is, at a specific voltage the distance travelled will be proportional to time. If that isn't the case, then I'll have to consider some form of rotation encoder.

Best wishes
Kevin

piborg's picture

This would be a really good idea, it would certainly make coding autonomous movement easier.

We did consider getting motors with the shaft protruding out of the back so encoders could be fitted, but there is not really enough room between them.

Using Hall effect would probably be easier to mount on the existing chassis as the magnets can simply be attached to the wheels.
The only trouble will be if the motors produce a large enough magnetic field to confuse the sensor when they are running at higher speeds.

sigpaw@hotmail.com's picture

I'm leaning towards the Hall device because it would be less susceptible to dirt/contaminants.

I too wondered about interference with the Hall Effect. But since field density decreases with the square of the distance, I'm thinking if I glue a magnet as far to the outside of the wheel as possible, the field generated by the motor should be negligible (fingers crossed). ;-)

Now to find a suitable device --- Mouser, here I come!

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