|
It would be great if our robot had a sense of direction. The dream is
beautiful but the reality not always looks the same.
Here is the electronic compass produced by Dinsmore
Sensors ($12 for digital and $35 for analog, which looks more
accurate). It indicates four cardinal directions N, E, S and W and four
intermediate NE, SE, SW, NW,
 |
The producer explains the how it is made: "Sensor is
a combination of a subminiature rotor jewel suspended in combination with
solid state Hall-effect IC's" .
OK. Now we know that this is just normal compass with four detectors
of a magnetic needle. We can't expect a miracle here. |
 |
Let's install it on the piece of universal board to connect
power supply and ground to each of four Hall-effect detectors. |
 |
It works! Here is the North! |
 |
And the North-West! |
 |
And the West... |
 |
And the South-West... |
 |
Finally the South. This is enough. |
The dynamics is not exciting either: according to the manual: 2.5-3.5s to
indicate the correct direction from full 90 degree displacement. Another
problem is that the compass must be operated in vertical position only.
The tilt should not exceed 12 degrees.
But, do we really need more?
What about external sources of magnetic field like DC motors? This is a real
problem.
 |
Here we have perfect indication. But where is TeamUR? |
 |
Just near by - an inch from the sensor. The indication
is not as good as before. |
It seems that we must be aware that the compass has limited applicability in
robotics. Unfortunately... | 
