Is there any issues with driving multiple IR Transmitters at the same time with the same frequency?
I want to create a WIFI IR transmitter and instead of having a single IR Trasmitter I want to have about 6 in a semi circle to better send to device in my lounge.
Chris
I assume you want all to be outputting the same signal at the same time.
This is simple as you just need to drive them all from the same IO via a transistor or MOSFET. A combination of serial and parallel connections of the number of LEDs required would work.
If the LEDS are driven from a 12v source you could have 5 or so in series (with a current limiting R). You could then have a number of these in parallel to cover the area required. It may work with 6 in one string. If not use two rings of 3. If you want to use only the 5v supply you would need to drop it to 2 per string.
Weedpharma
In a perfect world, there are no issues, but we don't live in a perfect world. 
A potential problem would arise if the receiver picked up light from two or more transmitters and one, or all, of the transmitters were out of phase with each other. While we assume that the transmitters will turn on and off at precisely the same time, in practice this may not be reality except for very slow signals. I would suggest using a single transmitter and a couple of cheap mirrors to bounce the signal around the room--perhaps now you have a good excuse to buy that disco ball you always wanted to hang in the lounge. 
Laser-Lance.
I see nor practical reason why the signals should be out of phase with each other. After all this is only 38KHz so in computer terms is very very slow.
Grumpy_Mike:
I see nor practical reason why the signals should be out of phase with each other. After all this is only 38KHz so in computer terms is very very slow.
Wavelength of IR is about 700nm. So there's every possiblity that the light from one LED will be out of phase with another when it reaches it's target.
KenF:
Wavelength of IR is about 700nm. So there's every possiblity that the light from one LED will be out of phase with another when it reaches it's target.
Oh come on. This light is not coherent so phase matters little. It matters even less when you are talking about a photo detector. This is just a silly comment designed to confuse beginners.
Grumpy_Mike:
Oh come on. This light is not coherent so phase matters little. It matters even less when you are talking about a photo detector. This is just a silly comment designed to confuse beginners.
Grumpy_Mike:
I see nor practical reason why the signals should be out of phase with each other. After all this is only 38KHz so in computer terms is very very slow.
The phase I'm referring to is the actual on/off [rise/fall] time of the transmitters, not the potential collisions of photons which could negate the signal. I didn't see the part where 38KHz is the frequency of the transmitter. If this was specified, then I wouldn't have commented. WiFi was specified and I assume WiFi data frequency to be 54MHz. At this frequency, the rise/fall times of the transmitters are pivotal to the function of the system and if there are multiple transmitters all running at 54MHz, then they need to be precisely synchronized.
Laser-Lance.
@LaserLance - I think you have got hold of the wrong end of the stick here. It is the IR transmitters that the OP wants to be simultaneous not the Wi-Fi.
I didn't see the part where 38KHz is the frequency of the transmitter.
It is the standard modulation frequency for IR transmitters, although it could range from 30KHz to 42KHz but that makes no odds to the answer.
your advice of :-
I would suggest using a single transmitter and a couple of cheap mirrors to bounce the signal around the room
Refers to the IR signal not the Wi-Fi does it not? There was never any suggestion that there were multiple Wi-Fi signals.
The Wi-Fi referred to :-
I want to create a WIFI IR transmitter and instead of having a single IR Trasmitter I want to have about 6 in a semi circle to better send to device in my lounge.
Makes it clear ( well to me ) that there is one Wi-Fi and at least 6 IR transmitters.
I can see no problem in that and indeed Weedpharma provided a perfectly correct answer in reply #1.
I guess the poster needs to be more clear about what the requirements are. I work with "IR Transmitters" that are extremely fast and completely capable of WiFi data rates so "standard" is relative here.