Wiring for a 3.5mm 2-pole IR emitter cable


can anyone confirm how the standard commercial IR emitter cables (3.5mm jack, 2 terminal, this sort of device: https://www.amazon.co.uk/Infrared-Extender-Extension-Transmitter-Compatible-Red/dp/B06WW6L2FK/ref=asc_df_B06WW6L2FK/?tag=googshopuk-21&linkCode=df0&hvadid=218081924305&hvpos=&hvnetw=g&hvrand=2791749134668735693&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=1007848&hvtargid=pla-716584661662&th=1) are wired?

I want to use one connected to a photon, to automate IR control of a heater I have.

Using the IRremote library and an IR receiver chip I’ve learned the raw commands for the heater.
But any attempt to drive an IR blaster similar to the one linked above using a standard setup (2n2222 transistor to switch 5V to the IR blaster) and the device does not appear to flash using my phone camera as a tester.

I suspect I am doing something wrong. I naively expected that the 2 connections on the 3.5mm jack are emitter diode anode and cathode, but … this does not seem to be right. Cannot find a datasheet, but these are quite common parts. I could sacrifice one and cut it up to investigate … but I thought I’d check if any of you find people know how to drive those emitters.

Any help gratefully accepted.

Did you test with a diode tester? (e.g. the diode setting on your DMM’s resistor settings)
Normally the tip would be anode and the sleeve the cathode of an IR diode.
There shouldn’t be much more to such an IR extender.

Yes … inconclusive is the best I could say :slight_smile:

Directly on the jack plug itself seems to show closed/high resistance in either direction but I don’t trust that entirely. And I have 2 of them bought at different times and unused so unlikely both broken …

Will investigate a bit further

and I just amazon primed a couple of IR emitters which come with a data sheet, so I will investigate a bit harder with those too.

The new IR emitters delivered from Amazon work fine.
So I guess those others were either a) bad or b) designed for a compatibility with some peculiar type of equipment …

Anyhow, all good.

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