[chbot] Odometry

[Helmut Walle]

Apologies for probably the slowest reply ever to any posting here...

Have you taken a look at he GMR components from NXP (used to be 
Philips Semiconductors)? If you can easily mount a small permanent 
magnet on the end of the motor shaft or wheel axle, you can position 
the GMR sensor next to it, and your encoder is ready. The only 
difference is that you don't get pulses, but sine waves instead, which 
should not be much of an issue in the age of readily available 
microcontrollers. The advantage of this solution is that it is very 
cheap, and quick and simple to set up. The GMR components are used in 
many high-volume applications where component cost and reliability are 
important, e.g., car accelerators. And they make nice compact and 
affordable encoders...

Kind regards,

Helmut.

+----------------+
| Helmut Walle   |
| walle@ww.co.nz |
| 03 - 388 39 54 |
+----------------+

On Tue, 31 Oct 2006, Carl Ranson wrote:

> 
> I'd like to modify my base to correct for the slight differences in the motors
> and thought that odometry might be the way to do it.
> 
> Anyone had experience with through hole type encoders (where the shaft goes
> through the encoder)?
> 
> What about the home made reflective ones?
> Ta
>