suppose there are two bots.their task is to detect each other and hit one another(as,i am participating in a sumo-bot competition). but if the two of them are using the same kind of sensors like ultrasonic or ir proximity (for object detection) then ,what will happen if they fight face to face? won't there be an interference of the ultrasonic sound wave or infrared ray of two bots?

what will happen??

and what is the solution if this happens?

  • $\begingroup$ They will interfere with each other. The only solution is to write an algorithm to differentiate interference from an actual signal, but if you are talking about constantly facing one another this will be pretty much impossible. The simplest solution would be to use a different method of detection. What sensors in particular are you trying to use and what do you expect to get out of them? Ultrasonic sensors are good for short range typically. I would look into computer vision as an alternative $\endgroup$
    – user241585
    Commented Jul 21, 2017 at 20:44
  • $\begingroup$ yes,they will face constantly... actually,i am participating in a sumobot competition.I have seen many online videos of this type of competition.in these videos they rarely use any type of computer vision... may be..(not sure).Isn't there any other solution? $\endgroup$ Commented Jul 22, 2017 at 2:27
  • $\begingroup$ Infrared sensors are much easier to use for this as they can be focused more specifically and are less likely.to.be I interfered with $\endgroup$
    – user241585
    Commented Jul 22, 2017 at 4:29
  • $\begingroup$ why won't they interfere? won't the infrared ray of opposite's bot come to my bot's ir receiver and cause bad readings? $\endgroup$ Commented Jul 22, 2017 at 5:42
  • $\begingroup$ I didn't say they wouldn't, I said it would be less likely. The sensors can be adjusted for frequency depending on which sensor module you use to cut down on interference also. It will also help to dial in the range and remove external interference from outside the ring. $\endgroup$
    – user241585
    Commented Jul 22, 2017 at 13:01

1 Answer 1


Because you have not specified any particular Infrared nor ultrasonic device only generic responses possible.

Infrared range finder devices which triangulate normally project a small focused light on the target. The receiver likely is only looking for the refection in a defined area. So interference from reflection of other infrared signals should be unlikely. However, if an infrared source was aimed at the receiver, it could flood it and cause an incorrect reading. Since normal transmitters project a small focused light, this too should be unlikely. But if the opponent wanted to, it may be possible to flood the play area with correctly modulated infrared light.

Ultrasonic range finders transmit and receive sounds waves timing all events. So there is only a small window when the range finder is expecting to hear an echo. Any sounds heard outside this window of time are likely ignored. It would appear unlikely that two independent ultrasonic range finders would encounter overlapping windows where they would be susceptible to unexpected interference. That said, it may be possible to flood the play area with the correct ultrasonic sound to cause the opponent problems.

Software solutions exist to deal with unintentional interference. Values that are known to be impossible can be rejected. Minimum of, say, 3 samples and Maximum of, say, 3 samples can be used to remove outliers. And averaging can be used to remove noise.

  • $\begingroup$ so,what will be the best option for me to use in my sumobot? please suggest one or anything better than this...I was saying about ultrasonic sensor "HC-SR04" and " Sharp IR proximity sensor " $\endgroup$ Commented Jul 22, 2017 at 16:15
  • $\begingroup$ I have yet to build a sumobot. But I would pick several Shap IR proximity sensors because of price, size and convenience of use. Use a CCD type camera (almost all digital cameras) to "see" where they are pointed. Consider height as well as angle from direction of travel when placing them. $\endgroup$
    – st2000
    Commented Jul 22, 2017 at 19:40
  • $\begingroup$ The best option would likely be LIDAR. Usually used in automated automobiles. But the size, power and price will likely outstrip lower budget project such as a sumobot. $\endgroup$
    – st2000
    Commented Jul 22, 2017 at 19:42

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