ir remote sender

I dont have an ir to radio to radio to ir system. its is just an ir reciever passing the signals it recieves straight on to the emitter. My understanding was that whatever signal was picked up by my reciever (with all different freq components) , if reproduced in exactly the same format by the emitter, would be understood by the intended recipient. Up to now I have only really considered that my LEDs were not being driven hard enough but your theory about dropped frequency components is worth looking at.

The thing is that:

1) The amp recognises everything. 2) The sattelite reciever ( and the DVD player to a lesser extent ) understand the signals intermittently.

This suggests that there is a problem but rather than something being missing from my system its just that something isnt working that well.

Ive checked the datasheets for transistors and the inverter that Im using to see if the rise times are fast enough and theyre in nanosecs. This wld be OK if the max signal freq is 40KHz. Anything else worth checking?

The reciever Im using is IR38D. I found it in an electronics kit from Maplin. Cant even find a datasheet for it on the internet.

The thing to remember is that the amp recognises the signal always and the sattelite reciever and dvd recognise it intermittently. This suggests to me that all the components are in place but something is not working quite as well as it should.

I dismantled one of the remotes, linked my led into it and placed it in the same spot and everything works well, so theres nothing wrong with the IR LED or its placement.

whats an AGC?

I couldnt really find anything on remotecentral, or its forums. Ill carry on looking maybe something will urn up.

On 20 May 2005 14:58:49 -0700, snipped-for-privacy@yahoo.com wroth:

IR controller type signals are not like ordinary serial signals such as RS-232. In most, but not all cases, the on/off pulses that you are probably reproducing well are themselves modulated or pulsed with a much higher frequency on/off signal. That high frequency component is required because most IR receivers are built like radio receivers with tuned front end stages to allow them to ignore interference from room lights and such.

I'm willing to bet dollars to donuts that your IR to radio Tx to radio Rx to IR chain of signal processing doesn't have the bandwidth necessary to pass the high frequency IR components. Those components are often around 40 KHz.

Jim

Most IR repeaters use a constant current source to feed the LED. That allows you to series string as many LEDs as the drive Voltage will support. What IR receiver do you have? most are tuned to a set carrier like 40 KHz. Not all brands of remotes use 40 K but most do.

Your problem may not be electronic at all. Remote repeaters can be a real pain to set up. If the equipment is in a dark area the AGC for the IR receiver may be saturating from your signal. If it works with the door open but not when it's closed that may be your problem. Very common and hard to fix at times. Try placing your IR emitter so it is reflected back to the equipment, this will reduce signal levels. You may need to play around with location for a while. Some of my installs took longer to get the repeaters to work than run wire and install the entire system.

Check out

the install forums have a lot of good information from people who have "been there, done that, got the T shirt" also links to IR formats and other good info.

Good luck! Tom

nanosecs.

lines.

The 38 makes me think that this has a 38KHz filter in it. Your remotes may not all use this frequency.IR30 Wreaks consecutive 30kHz. IR33 Wreaks consecutive 33kHz. IR36 Wreaks consecutive 36kHz. IR38 Wreaks consecutive 38kHz. IR40 Wreaks consecutive 40kHz. IR56 Wreaks consecutive 56kHz. Translation from a Czech page.

On 21 May 2005 12:46:58 -0700, snipped-for-privacy@yahoo.com wroth:

Sorry about the radio red herring. I read too much between the lines.

In any event, I still think you're dropping the 40 KHz "carrier" someplace. Do you have access to an oscilloscope?

Jim

AGC is Automatic Gain Control. In an IR receiver it adjusts the overall gain of the amp to correct for room lighting and stray signals. Check out this link, it may help.