1
\$\begingroup\$

I'm trying to find a datasheet for the receiver component in Snap Circuits part U24, which is an infrared light detector/receiver. It looks exactly like a TSOP382 sensor (picture below) but doesn't seem to work like one.

TSOP38238 sensor

Here's my understanding of how the component works:

  • Similar to an NPN transistor
  • Connect pin 1 to Vcc (5V)
  • Connect pin 2 to GND (0V) (similar to Emitter)
  • Connect load to pin 3 (LED in my case) (similar to Collector)
  • When infrared light is detected, pin 3 and pin 2 are connected, like in an NPN transistor

Again, I'm specifically looking for the datasheet or the exact name of the component.

\$\endgroup\$
  • \$\begingroup\$ It sounds like a pretty normal phototransistor? \$\endgroup\$ – Hearth Nov 18 '18 at 19:11
  • \$\begingroup\$ I think so but I need the datasheet and therefore the name of the component. \$\endgroup\$ – Kian Kasad Nov 18 '18 at 19:12
  • \$\begingroup\$ You're going to have trouble if you want the exact part number. This sounds like an extremely generic part. \$\endgroup\$ – Hearth Nov 18 '18 at 19:12
  • \$\begingroup\$ Yeah, I feared that. \$\endgroup\$ – Kian Kasad Nov 18 '18 at 19:14
  • 2
    \$\begingroup\$ If it IS a TSOP38238 , then you should be able to measure a resistance of roughly 30k ohm between the two outside pins...this is the pullup resistor between output pin and Vcc pin. Do this check with no power applied, and verify by measuring with ohmmeter probes swapped. \$\endgroup\$ – glen_geek Nov 18 '18 at 19:30
4
\$\begingroup\$

Looks like an infra-red receiver that's used for TV "remotes". These universally are encapsulated in black plastic that blocks visible light, but is transparent to infra-red light. These are far more complicated than a photo-transistor.

  • Two pins accept DC power between 3V and 5V.

  • A third pin is a digital output.

ir remote pinout IR remote internal block diagram

Most infrared receiver chips contain a pullup resistor between digital output pin and DC supply pin - roughly 30k ohms. This can be probed with an ohmmeter. It is unlikely that a phototransistor would measure 30k ohms between two pins, especially if you reversed the ohmmeter leads, and still measured 30k.

Your posted photo looks like a TSOP38238 , made by VISHAY. Vishay provides data sheets.
Its digital output pin pulls low only when it receives short bursts of 38kHz-modulated infrared light, such as that produced by many TV remote transmitters. Steadily shining infrared light at it produces no output (output remains "high").

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.