IR Communication by using PT2248/PT2249A

[munhann]

HI All,
Recently i build a IR communication circuit and still fails to figure out what went wrong..
I hope can get your expert help on this. Below are component list and attach files is my circuit schematics. Please help and this is urgent!!

TX IR Component List
- C1 = C2 = C3 = 120pF, C4 = 10nF (Polarized Capacitor)
- XTAL = 455Khz
- D1 = IN4002 and D2 = IN4148
- Q1 = Q2 = PNP A1015
- LED0 = Infrared Transmitting LED

RX IR Component List
- C1 = 100pf
- R1 = R2 = 39K
- 1738 IR Receiver (38Khz)
- PNP A1015
- Receiver IR Sensor

 

[munhann]

Anyone please help advices.

 

[SABorn]

I did have a quick look and was not sure if you had the code setup correctly between TX and RX.

What code are you sending on TX and how are you decoding that on the RX end.

 

[mdorian]

Hi , munhann, first , Q2 in the emitter cannot be A1015 because it's a NPN transistor. And find a higher current transistor, this has max 150mA, find one rated to at least 0.5 A
Between the battery and the IR LED you have D1 and a darlington transistor this goes to at least 1,6V voltage drop that leaves only 1,4V for the IR LED. You better leave D1 and use just one PNP transistor as in the datasheet.
In the datasheet I see three diodes from pin13 to pin 10 , 11 , 12 , leaving the pins 11 and 12 floating may have unexpected results.
And finally , don't forget to put a 2 ohm resistor in series with the IR LED because you can burn the LED if you didn't already.
After fixing this use your webcam to see if the emitter is working.

 

[munhann]

HI Mdorian, Thanks for great comments. I will go modify and updates you once i get the results.