robotmaker
I mostly know about every sensor made and run many many tests on them some for work but mostly for robot designs i ,might have well over 30 different types
ON sonars narrow detection is needed to mostly detect the corner of the 2 walls that meet for good navigation ,but also thin table legs or chair legs ,also doorways .
When a sonar transmitt a utrasonic pulse it sends like a cone shape.wider the cone shape wider the detection.
So there is 2 ways to do it,so far maxsonars sells smaller cone angles $30 each
Other way is easy with like SRF-04 types like EZB sells on the transmitt side you need to reduce the SIDE SLOPES or cone angle. its fairly easy only need a tube that fits on the outside of the ultrasonic tranducer and in the inside place a foam tube smaller the ID smaller the cone and length is about 1 1/2 inch long on the tube,can use cardboard type on foam tube inside length is about 1 inch try to match it to get a tight fit inside the cardboard tube
also best place to place them on robots is on each corner at 45 deg and then have 2 facing forward like headlights with no cardboard tube or foard to pick up wide angle objects
latter on will give you info on IR sensors too
And where do you find a "foam tube" like the squishy stuff?
mcmaster has plenty of them all sizes
foam tubes closed cell tubes all work and they have many more,kind the use for hot water pipe cooling i think the size i got was 5/8 OD 1/4 ID OR 1/2 OD will work too need to measure the OD of the transducer,i dont have one in my bedroom where i am now
Forgive me for sounding argumentative but have you tried narrowing the field of view with a plastic tube that slides over each sender /reciever? It seems like (and im no expert) that just a sleeve over the sensors that are longer by say 1/2" narrows the sensors view. The foam part doesn't seem absolutely needed though im sure it absorbs some "noise"
plastic doesnt work,i tried many types of materials only foam blocks the sonar thats why it wont detect foam stuff ,carpet or bedding or sofa's just like in speakers foam blocks sound, utrasonic receiver dont really need it ,it only picks up the return pulse
here is a guy who did much testing on it,and I did a little more to get a better detection.
reducing sidelobes on a sonar
Here is the Hero-1 way, it also incorporates foam.
You mention the best place for the sensors on a robot is on the corners at 45 degrees but that's not ideal on smaller robots such as the Omnibot or my Hearoid (same body) and probably the Omni 2000.
What position would you suggest for these robots? Also, is height a big factor and if so, what is better, higher or lower?
Also, I think I got the general idea of how to reduce the cone for the sonars EZ-Robots sell but is there any chance of a photo or sketch to reinforce this? Do I basically just put a small tube made from foam around the ping?
I'll make one and put up a photo shortly to hopefully help explain how I have read your instructions.
Nevermind, found your link which had a photo. I'll try this later on if I get chance as I am looking to find the best object avoidance method for my build.
I assume if narrowing the cone helps object avoidance and distance measuring then having the sonar on a servo for sweeping is not a good idea?