Combining Ultrasonic Distance Sensors

Thread Starter

djsfantasi

Joined Apr 11, 2010
5,683
Has anyone used this module? It’s similar to the Ping modules.
26394D85-1C1B-4227-9A10-E0E398637FDD.jpeg
B8A0DDE1-7AFF-46A3-86A6-90A631DD39DC.jpeg

I purchased a 5-pack from Amazon. There is an article somewhere that uses two modules to determine location as well as distance of an object. They block the transmitter of one with foam and tape. Then, they activate two modules at the same time, and with two separate distances, they triangulate to location of the detected object.

I want to remove one transducer instead of blocking it. I’m wondering if I need to replace it with some passive components? Instead of blocking it with foam...

And secondly, I would like to move the transducer so that I can place the receivers further apart and center the transducer between them. So, I plan on soldering wires to the removed transducer and mount it independently of the modules. Is this practical?

I’m going to wire up an experiment soon. But any input that can help will be greatly appreciated.
 

jpanhalt

Joined Jan 18, 2008
8,068
As for the modifications, I hoped the schematic would help. I did not go through it in detail, but I suspect there is an interaction between the receiver and transmitter to effect blanking of the receiver during transmission, so only reflected sound is detected. If that is the case, simply removing one TX without any connection to the other receiver will probably present some issues.

I have never built a line follower or robot to detect a source. But many years ago on a DC6 flight from LA to Memphis or return, the pilots invited me to the cockpit and let me listen to an AN beacon. I was quite young, but impressed. To this day, I would love to see someone use that principle instead of simply reflected intensity for object location. Here are some links from my files on object detection/line followers and the AN-beacons:

http://users.frii.com/dlc/robotics/projects/botproj.htm
http://www.inpharmix.com/jps/PID_Controller_For_Lego_Mindstorms_Robots.html

AN Beacon History:
http://www.navfltsm.addr.com/ndb-nav-history.htm

I know those are not specific to your question, except maybe the schematic, but I am assuming you want to locate a sound-reflective object.

John
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
5,683
As for the modifications, I hoped the schematic would help. I did not go through it in detail, but I suspect there is an interaction between the receiver and transmitter to effect blanking of the receiver during transmission, so only reflected sound is detected. If that is the case, simply removing one TX without any connection to the other receiver will probably present some issues.

I have never built a line follower or robot to detect a source. But many years ago on a DC6 flight from LA to Memphis or return, the pilots invited me to the cockpit and let me listen to an AN beacon. I was quite young, but impressed. To this day, I would love to see someone use that principle instead of simply reflected intensity for object location. Here are some links from my files on object detection/line followers and the AN-beacons:

http://users.frii.com/dlc/robotics/projects/botproj.htm
http://www.inpharmix.com/jps/PID_Controller_For_Lego_Mindstorms_Robots.html

AN Beacon History:
http://www.navfltsm.addr.com/ndb-nav-history.htm

I know those are not specific to your question, except maybe the schematic, but I am assuming you want to locate a sound-reflective object.

John
It’s for the penguin. I want to add sensors to locate something (a person) near it, so he can turn its head toward the person and talk.
 

AlbertHall

Joined Jun 4, 2014
8,506
As for the modifications, I hoped the schematic would help. I did not go through it in detail, but I suspect there is an interaction between the receiver and transmitter to effect blanking of the receiver during transmission, so only reflected sound is detected. If that is the case, simply removing one TX without any connection to the other receiver will probably present some issues.
If you trigger both boards simultaneously then the blanking will apply to both receivers even with one TX transducer covered (and also possibly with it removed if that doesn't upset the rest of the circuitry).
 

Thread Starter

djsfantasi

Joined Apr 11, 2010
5,683
I found the original article to which I referred:
http://forums.parallax.com/discussion/134899/triangulation-with-a-ping-array

I also researched Spice models for the transducer. There are several solutions, from a simple RLC model to more complex ones. Now, to learn how to calculate the values needed to create a dummy circuit to replace the specific transducer in the HC-SR04

I’ll experiment with your various suggestions. I’m beginning to realize that if I’m willing to use an extra pin, firing each individually might work. The large animatronics use an Arduino Mega, only because of the memory requirements of the a-code runtime. I am right at the flash limit. A delay between successive firings of 33ms appears to be sufficient; found a project online that fires multiple Ping’s and it used that delay. I doubt that the person/object is going to move an amount within 33ms that will confuse the animatronics triangulation of his/her/it’s location.

It’s way to easy to overthink. You guys deal with nanosecond accuracy. My projects are good with 0.5s of accuracy.
 

KeithWalker

Joined Jul 10, 2017
451
I found the original article to which I referred:
http://forums.parallax.com/discussion/134899/triangulation-with-a-ping-array

I also researched Spice models for the transducer. There are several solutions, from a simple RLC model to more complex ones. Now, to learn how to calculate the values needed to create a dummy circuit to replace the specific transducer in the HC-SR04

I’ll experiment with your various suggestions. I’m beginning to realize that if I’m willing to use an extra pin, firing each individually might work. The large animatronics use an Arduino Mega, only because of the memory requirements of the a-code runtime. I am right at the flash limit. A delay between successive firings of 33ms appears to be sufficient; found a project online that fires multiple Ping’s and it used that delay. I doubt that the person/object is going to move an amount within 33ms that will confuse the animatronics triangulation of his/her/it’s location.

It’s way to easy to overthink. You guys deal with nanosecond accuracy. My projects are good with 0.5s of accuracy.
There are a number of ways of doing this but I think you have come up with the optimum solution. There are no hardware modifications to make so the results should be quite predictable.
 
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