I am in a bit of a pickle. If anyone could help/has any ideas I will be very grateful - am aware this post is pretty long but thought if anyone was clever enough to know it would be you guys. If anyone needs more information/has ideas then I'm also listening! Thank you.

Have a specialist bit of kit which uses proximity sensors and would dearly like to be able to replace sensors on it with the same model. However, I am unable to ID the chip and manufacturer of product will not help. Therefore - does anyone know what chip this might be? The chip senses reflectance from a person from about 1cm to closer.

Visually inspecting the chip it consists of an LED and a sensor, separated by some dividing plastic. On the underside, it has 4 pads, with 4 microvias.

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Initially it looks like the chip was mounted on a small PCB but I think this is an integral part of the chip - or at least I have been unable to separate it with hot air. No markings anywhere other than an arrow of copper to indicate direction, on underside, as well as a slightly larger pad on the top layer of the "pcb" to again indicate LED.

On PCB layout it is measured as shown.

enter image description here

Pad layout on the chip is pretty similar. I was unable to measure the microvias so haven't included dimensions.

Pin layout is (from pin1 marked on PCB layout moving clockwise):

  1. Phototransistor/diode Anode
  2. IR LED Anode
  3. IR LED Cathode
  4. Phototransistor/diode Cathode

The phototransistor/diode is operating in reverse bias. Vcc is connected to pins 2 + 4. Pin 3 connected via current limiting resistor (100 ohm) to digital ground. Pin 4 is run to analog ground via 1k resistor w cap in parallel for noise reduction (standard voltage divider). It (pin 4) also runs to an ADC where measurement is taken. Vcc is approx 3.6V.

I don't have a spectrometre so am unable to confirm what wavelength of light is but I assume it's IR as it is not visible.

I have sketched the dimensions here -

enter image description here

I modelled it in fusion though my calipers are fairly budget so the accuracy may be slightly off(+-0.1mm). https://a360.co/2Kkbv5k

Thanks for the help!

  • \$\begingroup\$ Not quite sure why you want to take it off the board and re-install with some other one. If this is about repair due to the sensor being bad then this question is barely on topic here. Could you consider replacing the part with this one: vishay.com/docs/84285/vcnt2020.pdf \$\endgroup\$ – Michael Karas Jul 1 '18 at 15:37
  • \$\begingroup\$ We would like to be able to repair and also to design add on circuitry with more sensors that behave identically. Yes we are aware of lots of similar ones but would be especially good to be able to do an identical replacement. Thanks \$\endgroup\$ – Calum Nicoll Jul 1 '18 at 16:18
  • \$\begingroup\$ Goto newark.com/c/sensors-transducers/sensors/photo-interrupters/… \$\endgroup\$ – Gregory Kornblum Jul 1 '18 at 17:23

It's almost certainly the GP2S700HCP. Looks identical down to the microvias.


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Reflective optical sensor

QRE1113GR is one such example..

Turn on your mobile camera and observe one of the socket to emit IR closely to confirm.

enter image description here enter image description here

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  • \$\begingroup\$ Recent mobile cameras filter out IR. \$\endgroup\$ – Gregory Kornblum Jul 1 '18 at 18:17
  • \$\begingroup\$ Don't count on every camera picking up the IR. I tried 3 Apple products (iPhone X, iPhone 5, iPad) and none of them picked it up. A P&S Nikon S8100 camera does (looks white as on others). Nikon DSLR does not. Blackberry Priv dimly viewable. Logitech HD webcam, dimly viewable. Lumix P&S DMC-ZS7 viewable. All my notebooks have tape over the cameras so didn't try any of them. \$\endgroup\$ – Spehro Pefhany Jul 1 '18 at 18:43
  • \$\begingroup\$ @SpehroPefhany That's bad news. Phone camera was one of the debug tool for us.. How to observe IR now easily? \$\endgroup\$ – User323693 Jul 1 '18 at 19:24
  • \$\begingroup\$ Unfortunately this isn't the correct sensor - though I do have several of them on my desk and they are good, I'm looking for the exact model mentioned in my first post. \$\endgroup\$ – Calum Nicoll Jul 3 '18 at 13:59
  • \$\begingroup\$ I am sorry. I should delete this answer. It makes no sense..my bad. \$\endgroup\$ – User323693 Jul 3 '18 at 17:04

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