infrared UART project

[marian]

  Hello , i am traing to make a sistem of two opticaltransceivers one that take information from a termic sensor conected to an adc pin of ATMEGA 48 and the ather one on a computer using an MAX232 using infrared leds for transmitting.

 

   I saw a lot of projects similar and personally i have started from an remote control jamer that use an 555 timer circuit.

 the input of transmission circuit is taken from TX pin of anATMEGA48,  so i’m using uart interface that should modulate the 38 KHz – the out of 555 timer.

    Transmission rate is at 2400 bps and i kow it work and the 555 also i have watched on oscilloscopeand gave me 38 KHz but with the duty cycle somewhere  60 – 70 % and it also jums successfully all the tv remots.

    this is how i connect the output of 555 and the TX                                

     

 and this is the result, the modulated signal

    

  for reception i use an ir receiver TSOP31238 and the output goes to an max232 and on the computer.

 i send some control character but what i received is not what i send

 

    any ideas? i have also try to invert the output of TSOP31238 circuit

 

[Author]

Posts