More and more IR PIC ?s

I'm sorry to beat this to death but when I get one thing down, it opens more questions.

I have been reading several tutorials on sending pulses out using the 16F628 and I have found a couple of code examples that I like.

One turns on the IR for 9 instructions and then turns off the IR for 15 instructions and then repeats for X amount of times.

The other turns on for 13 then off for 10 and repeats for X amount of times.

What affect does this have on freq? Or other factors? We will be making/programming our own receiver if it makes a difference.

I found some code for a receiver that checks for the pulses and then compares the values. It only checks for how many times it pulsed and not so much on the data. This will work fine for what we want to do.

It would affect the duty cycle of the IR LED.

What you do is set the pin your using to oscillate at say 38khz
Then you turn it on 10us and that's a high 1
Then off for 20us that's a low 0
Now the Ir detector is checking for a signal that is riding on a 38khz carrier so to no that it is good data you would send out a start bit like a 1 that is 10us followed by a 40us low then the code you want to send 10us and 20us blocks I just used the time as example

Does the duty cycle need to match the receiver programming?

No it will affect the range. 30-35% LED on is common for IR transmitters, good compromise between range & battery life.

be80be said:

What you do is set the pin your using to osculate at say 38khz

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That's really fast kissing!!!

HA HA it was fast 38khz spelled that wrong didn't I oscillate

Osculate is a semi-archaic English word with several definitions.

* "To Kiss" - Latin osculatus, past participle of osculari, from osculum kiss, from diminutive of os mouth.

* Its primary definition is "to bring, or come into, close contact of union".

* In mathematics, it means "to touch so as to have a common tangent at the point of contact". See osculating circle, osculating curve, and osculating orbit.

* An additional definition is "to bring into focus or tune, to attune".

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