http://www.8051projects.net/ Learn to make simple microcontroller projects, pic, 8051, avr and arm projects. download 8051 projects, tutorials, libraries, sample codes. join the microcontroller discussion forum and ask doubts regarding electronics. the best source for 8051 over internet. en-gb 2009-01-07T22:47:08-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 i need circuit and configuration code to implement IR sensor led communication b/w microcontrollerand tell me frequencybaud rate,how to interface it. http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 Ajay IR sender: IR LEDIR Receiver: TSOP1738IR Frequency: 38KhzBaudrate: 1200bps (for good communication)Please make use of NE555 in astable multivibrator configuration for 38Khz square wave and 50% duty cycle. Connect the o/p of 8051's UART to RST pin of NE55. http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 hyogesh On the sender side I connected the IR LED & transmitted the data on 1200bbs & on the Receiver side I collected the data using the IR detector at 1200bps, but communication is not establishing between to 8051 controllers???The ckt explained above (IR Sender has how much baud rate & how u have connected the TSOP at the receiver side?) Can u give me the ckt diagram for the same & some help on it....Thanks http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 Ajay TSOP understands only PCM waveform so you need a 38Khz carrier wave for transmitting your data.TSOP is directly connected to 8051's RX pin but after you receive the data you need to complement it. http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 say2paul Ajay wrote ...TSOP understands only PCM waveform so you need a 38Khz carrier wave for transmitting your data.TSOP is directly connected to 8051's RX pin but after you receive the data you need to complement it.You mean to receive data from an IR transmitter (mobile phone/remote), TSOP's data pin can be directly connected to the RX pin of the 8051 micro Controller??If yes, can I use the same code to scan the data that I am using while serial connection of 8051 with Hyper Terminal? http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 say2paul you mean I have to connect the tx pin to a pc? Can't I leave the tx pin free?Or if i has to connect in anycase, can I connect it directly to an IR led? http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 Ajay well serial port can be only 1-1 connection. you cant use the same port for receiving and sending with two peripherals.rather.. if you use only rx pin of controller for IR reception then tx can be connected to PC like simplex communication. http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 sashijoseph You can very well leave the tx pin unconnected... http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 sashijoseph Ajay wrote ...TSOP understands only PCM waveform so you need a 38Khz carrier wave for transmitting your data.TSOP is directly connected to 8051's RX pin but after you receive the data you need to complement it.think you would have to invert the bits before it gets to the rx pin,else with the start and stop bits of the frame inverted,the controller will not be able to make out the serial frame. http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 say2paul sashijoseph wrote ...think you would have to invert the bits before it gets to the rx pin,else with the start and stop bits of the frame inverted,the controller will not be able to make out the serial frame.Dear Sashi, Can you please explain it in detail. I do not have any idea how to invert the bits..? http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 Arun Kumar V I do not have any idea how to invert the bits..?say2paul you can use "CPL" instruction in asm and in C you know the complement instructionArun http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 say2paul sorry I am newbie Can you please explain with C example..! http://www.8051projects.net/forum-t5286.html 2009-01-07T22:47:08-08:00 sashijoseph say2paul wrote ...sashijoseph wrote ...think you would have to invert the bits before it gets to the rx pin,else with the start and stop bits of the frame inverted,the controller will not be able to make out the serial frame.Dear Sashi, Can you please explain it in detail. I do not have any idea how to invert the bits..?Hi Paul,For an asynchronous transmission the data byte is sanwiched between a start bit and one or two stop bits.This constitutes a serial frame.The start bit is always 0 and stop bit(s) are always 1.Now,the tsop presents a low output when it receives a burst of ir ie with an input 1,it's output is 0.Similarly when it's input is 0 ie no ir,it's output is high.So when it receives the start bit it's output turns 1,instead of 0.This is read by the Rx pin which cannot decipher it as a start bit and hence the frame is not recognised.Thus you are required to invert the output of the tsop before it reaces the Rx pin and not in software.You could use a transistor inverter.