# IR transmitter too weak?

Following the instructables, I managed to map out the remote for my AC unit. I took apart an old remote and stole it's IR LED. Hooked it up to Pin 3 with a resister (I forget what I had on there, but I was using it with a regular LED with no trouble - maybe a 220?). Surprisingly, it worked pretty much out of the box.

HOWEVER, it needs to be REALLY, REALLY close to the IR receiver (say about one foot).

so I am trying to decide on one of two designs, but part of that depends on what you all tell me.

Question 1: Is the short range expected? How can I fix that? Pin 3 should be giving enough power, but should I provide a separate power source to it and feed it via transistor? Should I try dropping the resister level? Is it maybe a bad IR LED (it was pretty old, but I figure the original remote must have had more range than that).

Question 2: My plan is to use this all for home automation. I want to be able to tell me phone to turn on pretty much any IR appliance in the house. So there are two ways I can handle this.

Design A: A private army of little, cheap arduinos each one armed with a small IR led (maybe 2 for devices close together) and wiring the LED's right up against the receivers (like you do with a media closet).

Design B: Strategically placed IR LED's around the house each one covering a swatch of the room. intelligent decision on which IR can hit the device best (for this to work, I need to answer Question 1 above about why the short range).

Figuring that 1 is solvable because well..l. my remote works from across the room and I am sure you will tell me how to fix it... Which design would you suggest?

IR LEDs are limited in their range at normal ‘visible’ LED power levels. But, IR LEDs used for sending the usual remote codes can be driven with very high current levels with duty cycles below 1%. I.e., you’re on the right track with a separate power supply for the IR LED. Iirc, you can go upwards of 1A @ <1% duty cycle.

should I provide a separate power source to it and feed it via transistor?

Yes. There are plenty of designs on the web. Look up the TV-B-gone project.

Thank you for the replies!