Thread: lirc

me - a while ago...

Thats cool. I was looking at the schematic and it looks like they do alot of crazy stuff to get power to the actual IR Reciever. I don't see why one couldn't just supply it with +5vdc.

Originally Posted by TheLlama

Thats cool. I was looking at the schematic and it looks like they do alot of crazy stuff to get power to the actual IR Reciever. I don't see why one couldn't just supply it with +5vdc.

I'm not sure what receiver you are looking at but if i remember correctly I only used 5 components for mine, and ther was nothing crazy about. I thought it was very elegant and simple.

http://www.lirc.org/receivers.html

Scroll about 2/3rds down the page. It looks to me like the whole circuit is designed to power pin 2 of the receiver from the serial port's RTS signal. I guess the software will turn RTS high while the receiver is in use. I think this is just so no external power is required.

Mine will be mounted inside of my case, so +5V is readily available

I'd like to know if I can just eliminate the regulator; creating a circuit like:

Code:

 IC1 = TSOP 1738
+-----------------------+ 3                           R1 (4k7)
|               data -> +--------------------------------+--------o DCD
|                       |                                | 
|      ______________   |                               | |   
|     /                 |    +-----+----------------+   | |
|    (                  | 2  |     | +              |    |      
|     \______________ + +----+   -----              +----+--------o VCC
|                       |        -----                          
|                       | 1        |          
|                     - +----------+------------------------------o GND
+-----------------------+      C1 (4.7µF)

A little under that schematic on the lirc page, it says:

Instead of pulling the power supply from the serial port you can also use a different source like e.g. the USB port or the internal 5V line to power the circuit. Then you won't need a voltage regulator at all.

So, looks like you can definately get away with a different power source.

OK, I was just making sure I wasn't omitting any important parts. I almost leftout R1. However, R1 is a pull-up resistor, so it is essencial for a clean output.

as a side note, since its relevant to linux and lirc:

some sound cards have builtin ir ports. if you're using say the audigy nx, like me, or some other external usb cards, you can actually use alsa to configure the ir port. this is relatively new, so you may have to use the cvs versions of lirc and the latest version of alsa. it takes a bit to configure it, but it works quite well.

Originally Posted by ruzzmon

as a side note, since its relevant to linux and lirc:

some sound cards have builtin ir ports. if you're using say the audigy nx, like me, or some other external usb cards, you can actually use alsa to configure the ir port. this is relatively new, so you may have to use the cvs versions of lirc and the latest version of alsa. it takes a bit to configure it, but it works quite well.

Thanks, that is good to know.

I've built two IR receivers for use with LIRC (actually taught 13-16 year olds to build one of the simpler ones from the LIRC site), and I can tell you that for the parts costs, it's simpler to just find a cheap remote / serial port receiver combo that you don't have to worry about damaging.

I found a source on Ebay a couple years ago for old HP serial port receivers and remotes. They were something like $5 US, and everything is nicely encased and semi-water tight, so the receivers are quite durable. The remotes turned out to be not too shabby as well and worked famously with LIRC. I used to use my PC to control everything (TV-out to the TV, receiver always on the PC input at mid-volume), and this worked pretty flawlessly after being set up.

No matter which way you go for the receiver, you can't go wrong with LIRC. There are so many apps now with LIRC plugins.