I have an RSL Line Sensor which is designed to distinguish black and white lines. It detects white surface and gives me digital 1 as output, with 0 in case of black, but the surface needs to be close to it.

As it uses infra-red-sensors, I wanted to use this sensor as a proximity sensor, to tell me if there is a white surface near it. Is it possible to do this?

I think the only problem here is that we need to increase it's range of giving 1. Currently, it gives 1 only when white surface is too close to the sensors. I want 1 even if the white surface is there at a bit more distance.

Also there is an adjustable screw there to adjust something, under which POT is written. I am working with an Arduino.

  • $\begingroup$ Just out of interest, why do you particularly want to use this sensor as a proximity sensor? You can buy sensors which do what you want, like the Sharp GP2Y0A21YK (and its cheaper). $\endgroup$ Commented Sep 11, 2014 at 20:05
  • $\begingroup$ i had a competetion and we were given this particular sensor. i was just wondering if i can use this sensor to detect walls at a distance. it's over now!! $\endgroup$ Commented Sep 12, 2014 at 15:16
  • $\begingroup$ Anyway it's too late: you CAN'T use it in other way that line sensor (it just won't be reliable). $\endgroup$ Commented Sep 15, 2014 at 11:57
  • $\begingroup$ Does the sensor produce something other than 0 or 1 if the surface is not close enough? $\endgroup$
    – Ian
    Commented Sep 16, 2014 at 18:19
  • $\begingroup$ This is not very good answer. "reliable" needs to be qualified. I don't see any reason why a 0/1 sensor can't be used this way, assuming sensitivity can be increased as stated. A technical rebuttal or some insights would be a much better way to answer. $\endgroup$ Commented Oct 6, 2014 at 20:14

2 Answers 2


This would not be a good idea. As you can see in the specs of your sensor, it has a maximum range of 50mm. It's going to give you lots of faulty outputs if you try to use it for larger distances. My suggestion is to use a line sensor as a line sensor.

Three types of sensors are widely used as proximity sensors:

  1. IR sensors: Omits IR pulses and receives the reflection. The distance is calculated based on triangulation.

    • Pros:

      • Very Affordable.
    • Cons:

      • Not a good option for outdoors, because of high IR level in sunlight.
      • It has a noticeable lower range. For example, GP2Y0D21YK does not see obstacles closer than 10 cm.
  2. Sonar(ultrasonic) sensors: Sends sound pulses and receives the echo. The distance is calculated based on time of travel.

    • Pros:

      • Affordable.
      • Can be used in outdoor environment.
      • More accurate than IR sensor with less noise.
    • Cons:

      • Does not work very well with sound absorbing objects.
      • Might see ghost objects, because of receiving response after multiple reflections of the sound wave.
  3. LiDAR (laser range finder): Sends near IR, visible, or UV light pulses and measures the time of travel. The sensors come in one, two, and three dimensional.

    • Pros:

      • Very Accurate.
      • Works with a wide range of surfaces, outdoor or indoor.
    • Cons:

      • Not as affordable as the other two.

The sensors which you using as got just an comparator with a variable resistor to adjust the threshold to differentiate black and white line... Sensors with filters can you configured to find the distance from an obstacle which can be used as a proximity sensors .. Anyways proximity sensors are IR based sensors (you can verify using phones camera)...


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