Receiving IR signals with RTL-SDR dongles

R. X. Seger
Jul 4, 2016 · 15 min read
The RTL remote’s infrared LED turned on, as viewed through a digital camera
NooElec NESDR Mini 2+ teardown
The outside of the NooElec NESDR Mini 2+ showing the location of the IR sensor

Beyond RF into the IR spectrum

Electromagnetic spectrum showing visible light
Terahertz gap: technologies exist to rx/tx above (IR, etc.) and beyond (RF)

The Original DVB Tuner Software

Windows

RTL28328UHIDIR detected by Windows
REALTEK 2832U Device (RTL2832UBDA.sys, RTL2832UUSB.sys)

Linux: the dvb_usb_rtl28xxu driver

Remotes

A remote for the RTL-SDR, photo from @kolaCzek
Original Apple Remote
Some other remote controls, including the Siri Remote

Remote control protocols

Remote Control 5 protocol
NEC protocol modulation from SB-Projects

IR modulation explained

Introducing rtl_ir

rtl_ir showing the NEC protocol pulses for the RTL power button (0x4d), then 4 repeat codes

Aside: Software-defined IR, or translating IR to IQ samples

Sound card IR and alternatives

RF + IR, take #1: rtl_tcp -I

Integrating with dump1090-mutability

Using rtl_tcp and netcat

Using rtl_rpcd

Persistent rtl_rpcd daemon

Limitations

A simple application of IR: powering off the Pi

A juicy Raspberry Pi berry
A powered off Raspberry Pi 3

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