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 2008-12-01T23:16:35-08:00 contact@nospam.com hourly 1 2000-01-01T12:00+00:00 http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 HI GUYS,I m facing a problem how to count the pulse codes given by the IR sensor TSOP1738...i want program on the basis of which key is pressed in the remote...I m working on a home automation( IR) project, and i m using the PIC16F72 mcu.already i was enable the counter read the o/p of the IR sensor, but i don't know how to read the codes according to the key pressed......please help me, and send me some example codes.........ITS VERY URGENT......... this PROJECT DEAD LINE is on 18th july....help me................ http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 Ajay I hope you have read how RC5 remote works.. so the time for every bit is defined and fixed. After you sense the first low at pin where IR receiver is connected, you wait for fixed amount of time to read bits coming on the way with IR signal.You may need to do lot of testing as timing is always a problem.Try to start with something. Use my 8051 IR project as reference. It will help you.use 1736 for reception not 1738.PS: moving this post to PIC Discussion section. http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 electronicfreak what is the difference between 1738 and 1736,what is the problem with 1738....ur code is in C or it is in assembly language......thanx for ur suggetion..........may i know at what time u will be online...... http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 Ajay TSOP series is represented as TSOP17XXwhere XX means the modulating frequency.if you are modulating data to be sent at 38khz then you have to use TSOP1738 so that you can demodulate the signal successfully.RC5 remote use 36khz carrier frequency so you have to use TSOP1736 to demodulate the remote signal successfully.I dont have a fixed time for being online http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 sashijoseph Read this for RC5 ... http://www.ustr.net/infrared/infrared1.shtmlAnd here's Ajay's code in asm ... http://www.8051projects.net/downloads185.html http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 electronicfreak i m using the counter in microcontroller, it it increments the register when rising pulse occurs... is it a right right way to read the rc5 code...in ur prooject you r using the INT1 pin?it makes any difference http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 umibond hi u can use interrupts pins...it ill be easy way i think write ur counting program inside interrupt service routine...... http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 electronicfreak i dont know how to count a signal which connected to intrupt pin....please can u send me anyexample code......is it works like inbuilt counter as mentioned in my previous reply.. http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 electronicfreak thanx every one, i m using the PIC16F72 for this project ,and i m using synchronus counter on pin PC1...... there are 2 counter input pins , can i short them as u made it in above ckt............ http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 Ajay just use the timer in counter mode and i think you dont even need to use interrupt pin.whenever a the input signal complete its cycle counter will be incremented by one. Hence your pulses will get counted automatically. http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 pdi33 well, if there are two timer/counters in the PIC,i think u may need both of them, one in the counter mode to count the pulses and one in the timer mode (internal clock) to measure the time. just start the timer and counter simultaneously and read the counter value when the internal timer reaches a fixed pre determined value. http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 Ajay Electronicfreak, he is not angry on anyone Please take it lightly..anyway.. there are number of ways you can decode the IR signal. as i told you my asm code do the same. you can take it as a reference.I have considered the fixed timing of IR signal which is known as per RC5 protocol. other way is you calculate the timing on runtime by using timer controlled by interrupt.If you do the timer way, your program will become clock frequency independent. So you can use either way you want.You can download the code from download section and test it and analyze it carefully. http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 sashijoseph Guys,I think the OP wants to decode the RC5 codes rather than count pulses.Calling electronicfreak....... do you want to decode the RC5 pulses in order to determine which key was pressed or do you want to count the number of pulses received? http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 pdi33 right arun , i got it now. actually , i was thinking on the lines that the pulses are continuous, but the IR sensor would give a burst of pulses which can happen randomly in real time so yes, u need the interrupt to sense when that occurs, right?good thinking . http://www.8051projects.net/forum-t10679.html 2008-12-01T23:16:35-08:00 electronicfreak sashijoseph wrote ...Guys,I think the OP wants to decode the RC5 codes rather than count pulses.Calling electronicfreak....... do you want to decode the RC5 pulses in order to determine which key was pressed or do you want to count the number of pulses received?i want to determine which key was pressed .. which ever the way ,its counting pulses of the burst or the other