The IR Transmitter

The newest hardware implementation uses my prototype platform AVRstk with a ATMEGA328P processor and is called girt (Gnu Infrared Transceiver).

Figure 1. Girt on Avrstk

girt avrstk

Figure 2. Schematics

girt avrstk schematics

The software running on the avr has been developed using eclipse juno with the avr plug-in and made use of gcc-avr-4.8.2. A goal was to write the software in C, making use of a rather bigger microprocessor and use its peripherals as timers and uart and interrupts to get a source code that can be easy maintained and also ported to future microcontrollers.

The source code is girt-0.4.tar.gz and a compiled binary girt-atmega328p-0.4.elf/>

As already mentioned girt acts as a virtual com-port using a FTDI chip and can be observed using a terminals a gtkterm or miniterm. The baudrate is 19200 and intentionally kept low, to make buffer overruns on the girt software unlikely.

Figure 3. gtkterm


As can be seen in the terminal, girt used CSV, the first value is the command IRRX means received IR signal and the second field are the timer values for each signal change.


Your Linux distribution might restrict access to the com port as /dev/ttyUSB0 to fix that either work as root su or check what group /dev/ttyUSB0 belongs ls -l /dev/ttyUSB* and then add yourself to this group usermod -a -G <groupname><username>

The next steps would be converting avrstk into a dedicated girt device using an etched PCB.

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