Some time ago Joan investigated HC-SR02 ultrasonic sensors with oblique detection angle, it's interesting reading.gkraft wrote:Hi! This is my first post in these forums.
Some friends and I are building a robot for a school project. We decided to make one that has to be able to solve som tasks, one of them being to avoid collisions, i.e. it has to be able to turn if it finds a wall. We first thought about using an ultrasonic range finder. If it senses something getting closer the robot has to change course. Then we realized that the wall must be at a right angle for the sensor to give correct meassurements. We thought that a way of solving this was to attach it to a servo so that it could "look around" and then have the wall at a right angle in some position.
Is this a good way of solving the problem? Or should we use another sensor (and maybe method)?
Thanks in advance!
Unless your angle is so acute that you need to travel a long way to reach the wall (long corridor) the sensor will probably be able to detect the wall before you hit it.gkraft wrote:Thank you for your answer!
We'll probably go with the servo solution, but if we decide to have the sensor stationary it will still work you say?
Two wheel robots can spin on the spot, set one wheel forwards and one backwards and you have a very small turning circle.gkraft wrote:Those were very fast answers!
Thank you for your help! We'll probably try with the fixed sensor. But say that the robot is moving very close to a wall, but parallell to it and then reaches another wall. If the sensor is fixed it cannot look to the side and see that there is a wall there aswell and the robot may try to turn into the wall.
That depends on how close to the wall it has got. The sensor launches sound out in a (nearly) conical pattern so the closer the wall is the more likely the sensor will be picked up.gkraft wrote:But if the robot is too wide it will hit the wall while turning, right?
Don't forget to mention in your report that you had considered a single sensor on a servo mount and rejected due to the inherent delays. If the report documents negative events as well as positive it will be more interesting reading and more informative of the process you used in developing your project.gkraft wrote:We can actually do whatever we want for our project. It doesn't even have to be a robot. We could study fish if we want to, but we thought a robot would be fun. We have to come up with something to study and then write a report on it.
The three sensors solution sounds promising. Well probably use that solution. It uses less power which is important since we will be using batteries.