HDMI whisperer

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HDMI whisperer
Gestartet:	21.11.2015
Involvierte:	User:Phaer User:m68k User:Pk User:Jackie
Status:	active
Beschreibung:	It's a custom-built remote control interface for our cheap Chinese HDMI switches
Shutdownprozedur:
Zuletzt aktualisiert:	21.11.2015

What

Our HDMI switches provide only a classic infrared remote control, to interface easier with Slackomatic we replaced the infrared receiver with a few wav files and a small custom-built level shifter.

How

The cheap Sindax 5 to 1 HDMI switches we got have an IR remote control that comes with a 3.5mm audio connector to plug in a cape with a  TSOP383  AX-1838HS IR receiver module.

This receiver was plugged into the audio port of a laptop and the generated audio was captured.

That gave us 5 different audio files.

The files were post-edited using Audacity and now we can simply play them and attach the audio out from the Raspberry Pi directly to the HDMI switch IR receiver port with a small piece of voltage converter logic in between.

Data

Wav files with the recorded IR commands:

1. HDMI 1
2. HDMI 2
3. HDMI 3
4. HDMI 4
5. HDMI 5

The more or less mono files from above split into stereo files with only the left or right channel in use

Schematic

Circuit

the supply voltage is actually +3.3V instead of the shown +5V.

As NPN transistors we took 2x BC547B from Metalab's fine electronic parts stock).

Pictures