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Below you can see the device I'm trying to identify:

The incriminated part

It is mounted underneath the expression pedal in one of these:

DigiTech RP90

Basically, below the pedal there is a little plunger which gets closer or farther from the device. The end of the plunger which is facing the device is covered in a small amount of white paint.

My best attempt at an educated guess is therefore that the device is some kind of LED+photodiode/phototransistor combo, used to estimate the position of the footpedal.

Unfortunately, the ribbon cable that attaches the small daughterboard to the unit goes straight into a busy section of the main board, which makes it difficult to trace its surrounding circuitry. All of the surrounding circuitry is SMD resistors, capacitors and transistors, so my guess is that this device is analog.

The device has no discernible markings on its top or sides.

Does anyone recognize this? Does this kind of "split package" have a name I can start my search with?

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    \$\begingroup\$ Your guess is probably correct. You can try to turn it on and see if you can view the IR light with some old camera (ones that don't have a very good IR filter) and or measure it with a multimeter. p.s. the white paint would corroborate the IR sensor guess \$\endgroup\$ – Wesley Lee 2 days ago
  • \$\begingroup\$ Looks like an IR emitter and receiver. The top plastic looks different than the sides, probably so it can transmit IR. \$\endgroup\$ – Aaron 2 days ago
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    \$\begingroup\$ a smartphone camera "sees" IR very well \$\endgroup\$ – jsotola 2 days ago
  • \$\begingroup\$ @jsotola My hope is to identify the part so that I can reuse the enclosure & mechanism for other purposes. \$\endgroup\$ – Francesco Bertolaccini 2 days ago
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Did an image search for reflective optocoupler.

Found one that looks similar.

It may be a SFH 9245 Osram Opto, SMT Reflective Optical Sensor, Phototransistor Output.

Here is the datasheet.

https://docs.rs-online.com/aa9a/0900766b811e0651.pdf

edit: google osram reflective photointerrupter

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  • \$\begingroup\$ This is it! Thanks for providing the magic keywords, I'd never heard of a "photointerrupter" before \$\endgroup\$ – Francesco Bertolaccini 2 days ago

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