USB IR Receiver

USB IR Receiver Assembled

I have a mythtv box and it has pretty much changed the way I watch TV. Now I’m no longer tied down to the schedule set forth by the different channels. This is especially nice since I work at night and would not otherwise be home for prime time TV.

One of the biggest hurdles for the mythTV community seems to be providing an IR receiver so that you can use your remote control with it. I had been using a serial ir receiver but decided to try building my own USB receiver. This is based on the work by Dick Streefland found here: http://www.xs4all.nl/~dicks/avr/usbtiny/

I used his firmware but changed up the hardward just a bit. First off, the TSOP1738 is now obsolete so I had to find a replacement part for that. I also tweaked the setup used for the USB interface based on the schematics for the USBtinyISP by Ladyada.

Build You Own

Schematic

Here is a pretty messy schematic of the circuit. As I said before I fused together the work that Dick did for the project with the USB interface from Ladyada’s design. There is also a bit of difference with the new IR Module as I added the filtering capacitor and resistor that were recommended in the datasheet.

 

PCB Artwork

Here is the PCB Artwork needed to etch your own board (300dpi). This was one of my earlier attempts at PCB layout so its not the best but will do the job. You could also just use perf-board and point-point soldering if you are not able to etch your own boards.

 

Component Layout

Here is the component layout to assist in the assembly of the PCB.

 

Firmware: I used the main.hex file in the “ir” folder of Dick Streefland’s usbtiny-1.4 package. Get it here.
Software: When setting up LIRC you should choose the “igorplugusb” device driver.

Parts List:

Part	Value	Mouser Part #	Description
C1	27pf	80-C315C270J2G5CA	Ceramic Capacitor
C2	27pf	80-C315C270J2G5CA	Ceramic Capacitor
C3	0.1uf	80-C320C104K1R-TR	Ceramic Capacitor
C4	4k7uf	810-FK26X7R1C475K	Capacitor
C5	100uf	647-UPM1A101MED1TD	Electrolytic Capacitor
D1	1N5227B	512-1N5227B	Zener Diode 3.6V
D2	1N5227B	512-1N5227B	Zener Diode 3.6V
IC1	ATtiny2313	556-ATTINY2313-20PU	ATtiny2313 AVR Microcontroller
LED1			3mm LED
Q1	12MHz	815-ABL-12-B2	Crystal
R1	68	660-CF1/4C680J	1/4 Watt Resistor
R2	1k5	660-CF1/4C152J	1/4 Watt Resistor
R3	68	660-CF1/4C680J	1/4 Watt Resistor
R4	330		1/4 Watt Resistor
R5	22k	660-CF1/4CT52R223J	1/4 Watt Resistor
R6	100		1/4 Watt Resistor
R7	4k7		4k7 Resistor
SV1		571-5-146253-3	2×3 ISP Programming Header (optional)
U$1	TSOP4838	782-TSOP4838	IR Receiver Module 38kHz
X1	USB	649-61729-0010BLF	USB Connector