doughnut Posted November 4, 2020 Posted November 4, 2020 (edited) Hey folks, I am new on this excellent forum although have been a reader for a while. I am recently seem to be having a trouble with EV3 IR sensor. It always shows proximity ~40, even when there's nothing around. I understand it should be either 100 or 0, not 40? Remote control also behaves strangely. I had dropped the thing not so long ago, so I'm wondering if something is now wrong with it. Have anyone had a similar issue? How do I debug these things and check if it's broken? Is it worth writing to Lego support with this? Curious about people's experience. Thanks! Edited November 4, 2020 by doughnut grammar Quote
Tcm0 Posted November 5, 2020 Posted November 5, 2020 Can you let it see in different directions? Heaters and similar IR sources might interfere with the signal. Quote
Mr Jos Posted November 5, 2020 Posted November 5, 2020 The EV3 Ultrasonic measures distance in CM's, giving a distance between 0-2xx CM. It does not care what color the object is. The EV3 IR does give a distance, but it's based on light reflection. So depends on surroundings, colors in front, thicknesss of object etc. Depending on the location where my machines are it gives a different value for nearest position. This is why I programmed a calibration everytime the program is started to find the value for the shortest distance. Quote
doughnut Posted November 5, 2020 Author Posted November 5, 2020 On 11/5/2020 at 8:07 AM, Tcm0 said: Can you let it see in different directions? Heaters and similar IR sources might interfere with the signal. Expand oh yes, I tried in different locations and directions. I've never experienced this before with the sensor. On 11/5/2020 at 11:15 AM, Mr Jos said: The EV3 IR does give a distance, but it's based on light reflection. So depends on surroundings, colors in front, thicknesss of object etc. Depending on the location where my machines are it gives a different value for nearest position. This is why I programmed a calibration everytime the program is started to find the value for the shortest distance. Expand I tried in different locations (quite frankly, the location is always the same two rooms in my apartment) and in different light conditions. So does your sensor simply show different numbers or does the actual nearest distance it can "see" also change? What is the range of nearest distances your sensor can show? Quote
Mr Jos Posted November 5, 2020 Posted November 5, 2020 When I start my crane with clear view it shows around 80 PCT, when I put my hand around 10cm from it, it shows around 30PCT, when I put my hand against the IR it shows 0 PCT. My 2 other IR sensors on the other bricks show around 40-45 PCT when no boxes are in front, but the high bay rack is around 30cm away (thin pillars). When a box is on the chain conveyor it's around 30-40PCT, when the box is moved to the roller conveyors it shows 0-5 PCT. For these 3 IR sensors I don't use a calibration yet as the range is far enough to figure out positions. On this IR I used the calibration, as it measures the position of the crankcase of the press. The value changes fast and very accurate every rotation the yellow liftarms pass close by in front. When the crankcase is down (clear view) this IR shows around 30PCT, as it does kind of detect the items under/low in front of the sensor. Goes to around 10PCT when the liftarm is 0,5cm away. I do have to say I like the IR sensors more then UltraSonic for accurate positioning, US seems to float more. IR is more precisely when running in same conditions and when the distance is not to big! If you want to measure distances around 50cm or more the IR is not a good choice. Quote
doughnut Posted November 11, 2020 Author Posted November 11, 2020 wow, some awesome creations detected! Interesting. My sensor shows ~40 max at the moment, and it doesn't "see" anything farther away than ~80cm away. I think that's approx the actual maximum distance. So yeah, it looks like I might need some calibration on the software side. Thank you folks, the sensor now makes a bit more sense to me! Quote
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