Navigation in the underwater environment is not as easy as on the ground. You have only images from a camera, no sun, no characteristic points, water is not as clear as the air. Expensive commercial vehicles uses sonar, but for homebuilt ROV an old fashioned compass is enough. There are two main solutions using:
It is worth to mention that you must be careful installing a compass in the robot. It can be affected by electronic components and electric engines. Analog compass
The idea is simple, you must attach classic compass to the robot in a way you can see it in the camera. If your compass is not waterproof or can not handle high pressure you can use little trick. Put the compass into camera housing and attach a mirror in the front of camera (not in housing). You can see the compass Use car compass (not "flat") with a ball. Similar to the one shown on the left. It costs about 3€. For practical use, look at Subz NZ page. Digital compass
Digital compass can be easily connected to micro controller. Very popular design use Dinsmore 1490 chip. Two combined units provides only 8 headings (N, NE, E, SE, S, SW, W, and NW). For more details look at Arrick If you need more accuracy you must use different chip. Here you have a list of popular ones:
For more links look at Brooke's Home Page. If you do not want to build a digital compass from scratch, you can buy a compass module. It is PCB with one of the above chips.
If you would like to build digital compass from scratch you need 2 KMZ51 (or 1 KMZ52) chips and accelerometer chip for tilt compensation, e.g. ADXL320. Here are some links:
|
|||
 |
||
|
|
