IR demodulator

[miscreant]

I had this idea but it did not work.

I used an IR LED to transmit a modulated stream of pulses. The RX is a TSOP 1738. Now, the 1738 outputs data serially. since i am using a simple 16f84a for a micro, i cant use UART to obtain data. so what i did was that i used a 4 bit shift register, configured as serial in parallel out. the parallel outputs can be easily interfaced with the PIC.

I am runnin the register clock at 38 Mhz, the frequency at which the IR LED is running. the circuit sans the register works with another microcontroller which can accept serial data but i NEED to make it run with a 16f84a. any suggestions ???

 

[Roff]

You may have scared off potential help with your "38Mhz". How about 38kHz?
Trying to sync a remote signal to a local clock, at the data rate,seems to me like it would be impossible unless you phaselock the clock to the data. Can you implement a UART in software?

 

[Nigel Goodwin]

I suggest you check my IR PIC tutorial, it uses the 16F628 (rather than the obselete 84), but you could use an 84 if you still have old ones available.

There are specific reasons you can't just send standard serial data via IR (for one thing, the pulse width out of the receiver isn't the same as that transmitted). My tutorial uses the Sony SIRC's system, but another popular method is Manchester coding - this is used in the Philips RC5 system.