A sensitive IR detector for capturing and digitizing weak infrared signals
KiCad
Latest commit e4a9ae2 Aug 10, 2016 @devttys0 Added test points TP1 and TP2 for monitoring the signal before and af…
…ter DC blocking capacitor C4.

README.md

What?

IRis is a low power, low cost, high sensitivity infrared detector designed for capturing raw IR digital data transmissions. Think of it like a mon0 interface for IR.

Why?

Typical IR receivers are designed to work with common IR remote controls, and as such they ignore any IR signals that are not modulated at 36-38kHz. But there is so much more to the world of IR than this!

In contrast, IRis was designed to be a simple, general purpose IR detector to aid in the capture and analysis of raw IR transmissions, in particular low data rate signals such as those emitted by chell phone proximity sensors.

Who?

The brainchild of Dale Wooden, and designed by Craig Heffner, IRis is of use to anyone interested in exploring the hidden world of IR around them!

How?

Most IR data is transmitted via on/off pulses (i.e., on-off keying). Powered from a single CR2032 coin cell battery, IRis uses a a sensitive photodiode, high gain transimpedance amplifier, and comparator to detect even very weak IR signals and convert them back into clean digital pulses that can be interpreted and analyzed by nearly any digital system, such as an Arduino or Raspberry Pi. Just connect to the IRis' output pins (connector P1) and point it at an IR source!

Due to its high sensitivity, best performance is obtained by preventing unwanted or ambient light from hitting the IRis photodiode. In conditions where there is low ambient light this is not a major problem, and in areas of greater illumination the issue can be mitigated by placing a shroud around the IR detector to prevent direct contact with unwated light. IR filters can also be used to reduce interference from unwanted light sources, but bear in mind that some bright light sources (e.g., the sun!) emit IR radiation as well.

IRis is still able to detect IR transmissions in the presence of bright ambient light, but at a reduced distance.

How Much?

PCBs (1.24 inches in diameter) are available from OSHPark for less than $8, and components can be ordered in single quantities from Digikey for an additional $8.

IRis PCB 3D View