Suggestions on sensor placement and use for Jeeves 3.0

noobmuncher

Hello all, Seasons greetings!

I have a robot i have been working on for a few months now dubbed "jeeves" he has now gone through 2 full rebuilds and now is going through his third.· He is about a meter high, cylinder shaped with a domed head and about 1 foot in diameter.· in the past i havwe used one infared sensor pointed down at a 45 degree angle from near the top to detect low objects and a ping sensor on the front which pivots to find the farthest path.· Now with a dramatic change to the components along with the program I am using a minimum of 2 ir sensors (the one on the left with point right the one on the right pointing left, both at angles so that the fron of the robot is covered).· The issue i am having is deciding how to cover the full meter high robot with sensors so that all objects are detected not just low lying ones.· This problem has occured because the program was originally for a very short rover robot and did not require multiple sensors.· It allows the robot to be in constant motion while avoiding objects.·
Anyhow any ideas? I was thinking putting 2 more IR sensors near the top of the robot therefor having 4 sensors to detect objects and forgetting about the ping for object avoidance.· Or I could have it facing straight forward at the top and have it act as a sensor telling the robot of impending collision.·
Hopefully you guys have some suggestions, sorry i was so indescriptive and didn´t post pictures, but I am in a such as well as not on my home computer.

Thanks
·

Mike Green

Some objects reflect IR well and some do not. Some objects reflect ultrasound well and some do not. If you use just one kind of sensor, you will miss more object detection cases than if you had at least two different kinds of sensors. The various sensors' documentation describes their "field of view" and you should use that to decide how many sensors you'll need to cover the field of view that you want. You could do quite well with two PING))) sensors on servo driven brackets with IR sensors mounted above the PING))) and facing in the same direction. If you mount them one above the other with slightly different angles, you'd cover the whole front of the robot (180 degrees horizontally) over a pretty full range vertically close in. Further out, either sensor will cover the height of the robot.

MovieMaker

would like to see some pix when you have the ability.

noobmuncher

Here are some pictures of what it currently looks like with the ping sensor up top scanning back and forth and the Sharp IR sensor facing at an angle down. What i am trying to do is follow a similar structure to the diagram i have drawn up here (sorry it's crude). The two IR sensors would be near floor level while the ping is near the top. The IR sensor that is shown in the actual picture would be one of the ones moved to the bottom side. Would this work? How would i do it?

Mike i like your idea, but can you clarify it so i am having a servo on either side rotating horizontally? Or 2 at different heights rotating horizontally?

Thanks

Mike Green

A single PING has a cone shaped pattern to the ultrasonic beam. With horizontal servo movement, you can get over 180 degree coverage in a band. The PING documentation shows the size of the cone and you can figure the range where the coverage becomes complete (where the band extends to the floor). By mounting one PING near the top and another PING about 1/3 of the way up from the floor, you can get complete close coverage as well.

noobmuncher

Excellent thanks Mike!· That will work perfectly!
Thanks everybody!

MovieMaker

Thanks for Posting the pix. Good looking robot. What Mike says should work.