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Asked — Edited

Ir Distance Sensor

Touching on it in an earlier topic it's advised that I include both ultrasonic and infrared sensors for distance/collision detection.

I know there is a mention of the Sharp GP2D12 in the tutorials but it seems I cannot source this in the UK. I can find the Sharp GP2Y0A41SK0F though, would this work?

To save looking it up the basics are;

As distance increases the voltage (Vo) decreases from +3v to around +0.3v The three pins are Vcc, Vo and Ground, I assume Vcc is +5v, Vo is the signal wire and Ground obviously Ground? Plugged in to an analogue port?

It measures distances from 4cm to 30cm, which is fine for what I need it for, it only needs to know if it gets within around 3 or 4 inches (7.5-10cm)


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With no replies I decided to just try it, it does work although the range is much shorter than the unavailable & discontinued sharp ir sensor in the tutorials.

IR collision detection works fine, set to stop if over 35 and it stops a few inches away from obstacles but the IR Radar doesn't work...

@DJ_Sures how do we calibrate the IR sensor for the radar? One of the options is "minimum distance before turn (inches)" but even setting this as high 60 doesn't make my robot turn. The Radar doesn't plot any red dots but the distance shown below the radar is reporting (between 255 and 120 on mine).

As the GP2D12 is discontinued and there are various other IR sensors with various ranges etc. wouldn't it be an idea to add calibration of the sensor to the settings/config like the ADC meter config has the setting to do this? I realise the list of things to do may be large but hope this gets added to it (and while I don't know the specifics of how ARC is written and updated from my experience this doesn't sound too hard to implement so hopefully a nice easy one for DJ)

Any help would be appreciated in getting the IR to control the Movement Panel as ultrasonic doesn't seem to pick everything up but between the two it should be perfect, even if it's just a quick fix at this stage.

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Thanks, I found that last night when I did a better search after posting.

It looks like it's been an issue for a while, is it something that's being worked on @DJ?

P.S. Just read my posts back and would like to point out that I wasn't trying to be a pain in the rear end about this nor demanding answers etc. I guess that's the problem with text based communications, you can't judge the context it was meant in... If there's anything I can do to help solve the issue I'd be more than happy to help.


Hi Rich! Long time no see!:) I also just went accross the same problem. Did you find a solution, beside going for ultrasonic instead of IR? It is weird how it is impossible to calibrate the IR radar and the fact that it doesn't go below 121 detection.

Do you know how you get your motors to stop using the Collision Detection instead of IR Radar window? This one seems to provide with workable values but I don't know how to make motors stop upon reaching the threshold collision value.

Thanks in advance,