Flirc USB IR Receiver Pinout Help

[whatthedonut]

Hello,

Does anyone know the pinout of the IR receiver on the Flirc USB? I would like to modify the device to add a female 3.5mm mono plug to the device rather than sticking an IR flasher on there.

When I open the plastic cover of the Flirc USB, I see 4 solder pads under the IR receiver on the bottom of the circuit board. I think I've figured out +V pinout is the right-most solder pad under the "C" of the screenprinted FLIRC logo. More importantly, I need help to understand which is the "signal" and "ground" pads.

Any help is appreciated. Thank you!

[jason]

Here you go buddy: http://www.vishay.com/docs/81764/tsop852.pdf

[whatthedonut]

Thank you. However, the receiver on the Flirc USB is 4-pin, not 5-pin.

[yawor]

It could be http://www.vishay.com/docs/82495/tsop753.pdf

It's fairly safe to assume that the pin-out is compatible even if this isn't the exact chip used. Don't look at the pads at the bottom of the PCB because those are test pads and don't have anything to do with the IR module.

I'm wondering what do you plan on connecting to the PCB. You've said that you want to install 2-pole (mono) mini-jack. But to properly use IR module you need 3-pole connection so you can connect V+, ground and output pins. You can't just use a simple 2-pin photo-diode because Flirc microprocessor is expecting already demodulated data. The IR module is a photo-diode with a demodulation logic built-in.

[whatthedonut]

Thank you. From some snooping around on the Vishay website, I figured that the receiver on our unit was like the TSOP752 and all the variants have the same 4-pin layout so pin 3 = Signal Out. With this knowledge, I played around with the unit last night and came to the same conclusion that simply soldering the leads of a plug will not work. However, I think I've found a solution.

I removed the surface mount IR receiver and had direct access to the solder pads underneath. Using a multimeter on the continuity testing mode, I figured out the solder pads underneath the circuit board and those under the IR receiver were not the same. I soldered the two leads from my mono plug to the "OUT" and :Ground" pins under the IR receiver. I hooked this up to my IR repeater system and the Flirc USB to my laptop. When I tried to teach the Flirc some remote codes (through the IR receiver on my IR repeater system), the USB would disconnect/reconnect to my laptop and the software would flash a "Transfer error." The device registered some action, but it was not the expected input and the hardware/software crashed.

I researched some more and found a relevant post at avsforum. I plan on using an optocoupler with 2 legs connected to the FLIRC and the other two legs connected to the 3.5mm mono plug (essentially in between the Flirc USB and the 3.5mm mono plug). If I understand correctly, I think the optocoupler will demodulate the incoming IR signals.

[yawor]

First of all I've already told you that the pads on the back side of the PCB weren't the same as the ones for the IR module on the top side. These pads are for testing or programming purposes and are probably connected directly to the microprocessor. You could easily fry the microprocessor by connecting something that is not designed to connect to these pads.

I think that the repeater system may be using a RAW modulated IR signal instead of a demodulated one. Flirc is not designed to receive such signal and wont recognize the input even if you pass it through an optocoupler. Of course there is a change that the repeater system you have is actually using demodulated data but I doubt it because it would require an extra logic inside each of the transmitters and they probably are just a simple IR transmitter diodes. If I'm right then you would need to buy VSOP38338 which is an IR demodulator module without the IR receiver built-in. You could replace the IR module on the Flirc with this chip (it's not compatible pin-to-pin so you could not solder it directly on the board but with some short wires). You can then connect output from your IR repeater system to the input pin on the new chip. That should be done via optocoupler (Flirc <-> VSOP38338 <-> optocoupler <-> IR repeater system).

Then this has some change of working :).