I'd like to reuse the IR Extender cable that came with my H6400 TV and transform it into an IR blaster to control my AC unit. But, to do this I'd like to understand how it's built (does anyone have a schematic?) and also what voltages/currents I can apply to it to work.
I will be controlling it from a Odroid XU4 which has TTL1.8V logic, but I'll be using a transistor and can feed it from 5V (and probably a max of 100mA).
I'm guessing the limited range when using it to enter the extended service menu is due to the limited current it gets from the headphone jack, right? From what I've read the voltage could vary from 0.3V to 2V, and current should be around 15mA: http://electronics.stackexchange.com/qu ... om-a-phone
Anyone else tried this already?
Here are some images of the inside of the IR extender and an approximate electrical diagram.
Now, the problem is identifying the parameters of these IR LEDs - what is their direct voltage drop and their maximum forward current. From various sites online I could gather that the voltage drop for an IR LED is between 1.4-1.6V and the current is around 50mA. Any ideas how I can test these in a controlled fashion in order not to burn the LEDs out?
My plan is to use the extender (which is about 3m in length) to control an AC unit. The IR leds will be around 20-30cm away from the AC unit's receiver.
I'm guessing I won't be needing 50*5=250mA of current, because when using the extender with a PC to enter the service menu, the PC's headphone jack is not outputting more than 20-30mA.