Can I somehow use Vishay's TSOP series IR receivers and IR LEDs to measure the distance from an object? Has anyone done that before or has any idea how one could do it(clever programming or circuitry, maybe?)?
32.3k 6 6 gold badges 81 81 silver badges 139 139 bronze badges asked Nov 27, 2010 at 18:01 465 2 2 gold badges 7 7 silver badges 12 12 bronze badges\$\begingroup\$ TSOP is a series of IR receivers by Vishay, here it doesn't mean "thin small outline package" or something like that. Right, gomek? \$\endgroup\$
Commented Nov 27, 2010 at 19:14 \$\begingroup\$ That's right stevenvh. \$\endgroup\$ Commented Nov 28, 2010 at 5:26\$\begingroup\$ Please do not use the TSOP acronym as a general purpose noun for infrared receivers. TSOP is far more commonly used to refer to a specific type of IC package, and it makes the question very confusing. \$\endgroup\$
Commented Nov 28, 2010 at 13:31\$\begingroup\$ Have you considered using an Ultrasonic Sensor for distance measurement? There are a few that are out there and being used in the industry to do the same. Or is that you have to/want to use IR Receivers? \$\endgroup\$
Commented Nov 28, 2010 at 22:43\$\begingroup\$ Why do people suggest different things when people want to do one thing? \$\endgroup\$
Commented Oct 3, 2012 at 10:1310.8k 20 20 gold badges 64 64 silver badges 89 89 bronze badges answered Oct 2, 2012 at 20:54 41 1 1 bronze badge \$\begingroup\$Many other applications require a reflective sensor that detects not only presence but also proximity by measuring the strength or weakness of the reflected signal. Instead of a fixed detection threshold, analog information from the sensor is needed. This is possible with the TSOP4038, TSOP58038, and TSOP58P38 IR proximity sensors. The length of the sensor’s output pulse in response to the emitter signal varies in proportion to the amount of light reflected from the object being detected. For near objects, the output pulse approaches 100 % of the emitted pulse, for far objects the output pulse becomes shorter.
I doubt you could do better than just detect the obstacle this way. What you need is a device like Sharp GP2D12, which measures distance between 10cm and 80cm. About USD 10, IIRC.
answered Nov 27, 2010 at 18:56 146k 21 21 gold badges 458 458 silver badges 669 669 bronze badges\$\begingroup\$ I just discussed a method but I agree with Stevenvh, if there is a device to do it you are much better off. +1 \$\endgroup\$
Commented Nov 27, 2010 at 19:08 \$\begingroup\$You will need to have to approach it one of a different ways. one method would be to sweep what power you are radiating with the LED (something like a digital potentiometer to control the current) so that different range of objects will be detected.
It is very important that you recognize different materials will reflect IR differently making it very hard to get accurate results unless you know what materials will exist. The Receivers also have automatic gain control that will remove a continuous signal at the frequency and can remove yours if you send it continuously.
answered Nov 27, 2010 at 19:07 13.5k 8 8 gold badges 62 62 silver badges 85 85 bronze badges \$\begingroup\$You can get some effective LED power control by adjusting the mark/space ratio of the 37khz carrier. However it isn't a good way to get any sort of repeatable distance info - could be useful for object detection and approach/retreat discrimination . Elmos's Halios can do IR ranging by comparing reflected light with a local reference signal, but unless you're designing high volumes there are cheaper and simpler ways.
answered Nov 27, 2010 at 22:56 mikeselectricstuff mikeselectricstuff 10.7k 34 34 silver badges 34 34 bronze badges \$\begingroup\$Yes. You can sweep modulation of frequency of the transmitter and use the very sharp roll of of sensitivity around 38kHz of the receiver to estimate distance based on signal. It is not that accurate though and is influenced by ambient light as are other IR distance sensors that rely on output amplitude for distance measurement. You can also get interference from sunlight and Fluorescent lamps among other things. But you can derive a distance scale based on frequency ranges up the receiver sensitivity slope. You know what frequencies let an object be detected so can estimate how far based on prior calibration tests. I did this in 2012 using Parallax Arduino BOEBOT kit.
answered Jun 30, 2020 at 0:58 \$\begingroup\$ Mind sharing how you did this? \$\endgroup\$ Commented Jun 30, 2020 at 5:33To subscribe to this RSS feed, copy and paste this URL into your RSS reader.
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