Record IR Pulse Pattern

Hi all....I am trying to build a Multi Channel IR Remote Control...The problem is i have access to only unbranded cheap remotes,which dont follow RC5 or similar protocol......So,..one solution is to hook it up to a CRO,and measure the pulse pattern,make a note of the timing involved and write the code accordingly.

However,I dont have access to a CRO ....what i thought next was,why dont i *record* the incoming pulse pattern onto the memory bank of the 8051 (via the IR Receiver TSOP 1738 connected to an appropriate pin),by monitoring the pin in someway...and then,when i have all the pulse patterns stored in the memory,i can use flash magic to view the memory,and then note down the 'recorded' pulse patterns and use the info to write the program....or i can also tell my program to directly use them from wherever they are stored......... Problem is....I dont know how to 'Record' this pulse pattern by monitoring the pin the IR receiver is connected to....could someone shed some light on this?....Many thnX!

Maybe somewhere later down the line,i can code a 'Learning Mode'...i.e using a suitable mechanism,it can record,store & implement IR Pulses of *any* remote...it could go like this... press a membrane switch,it goes into learning mode....press a button on the remote whose pulse pattern u want it to learn...then press the button again,signalling it to become ready to accept the 2nd button's pulse pattern and so on.....so,if its an 8channel remote...u can program 8 *any* keys of *any* remote(s?? )......Pls help me out for this recording mechanism! ...thnx!

hi, you can record the ir pulse using your soundcard input ( mic) and analyze the recorded sound file (wav file) on any audio editing software.

here the diagram :




the sensor is any IR photo diode , resistor can be 4.7K one

Arun

yes..but if i want to record onto the microcon itself?..waht would the algorithim be then?

you can do that by sampling it at fixed interval and reading the port pint at that sample. sample rate may be defined by your or if pulse is having a fixed frequency you can use the same freq for sampling.

...So what u are saying......is: every 1ms,(after IR has been detected) i check the state of the pin and note down the state somewhere in the memory?.....that can be done....can u give me an idea of how long an entire pulse train is usually?...and what could be a good time interval to check the pin..?

well it actually depends on what type of input signal is. i mean frequency of i/p signal. format of i/p signal, encoding of i/p signal. you cannot define things on your own.

yes..but if i want to record onto the microcon itself?..waht would the algorithim be then?

the method i suggested does that, it helps you to analyze the timing of the pulse train and then you define your sampling freq. in the micro.

as ajay already said, its not so easy to just stick a Ir sensor to micro's pin and start logging the data. you first need to know the format used, filter out the Carrier freq., define sampling frequency then adjust the latency time etc.

Arun