315 Mhz RF link kit

be80be

Well-Known Member

• Apr 6, 2012

• #1

I was going to write code for one of these first time using.

This is the deal there really no data sheet and what Itead Studio Has posted is links to ardunio and avr

So after a long look at some code and a picture of the output it looks like this thing is keyed high going low, Not low going high.

Is this right

Here a pic to show what I'm saying
View attachment 63079

 

Last edited: Apr 6, 2012

Nigel Goodwin

Super Moderator

Most Helpful Member

• Apr 6, 2012

• #2

It's quite possible, IR receiver IC's work that way as well - it really makes absolutely no difference.

 

be80be

Well-Known Member

• Apr 6, 2012

• #3

I was thinking that I just wondered if and one really new.

It's low going hi now to write some more code

The Receiver output looks good at 1200 baud sending numbers 123

I'm thinking more like write code to look for a start bit of 2.45mS and 3 bits and stop bit

2.45mS start
.65mS low bit
1.25mS high bit
The stop bit would be if the line is high for 3.75mS

 

Last edited by a moderator: Sep 10, 2013

Nigel Goodwin

Super Moderator

Most Helpful Member

• Apr 7, 2012

• #4

The normal way is to use Manchester coding, and send packets of data.

A scheme using variable bit widths is what Sony SIRC does, and it will work just as well for RF as for IR - however, it's relatively slow, and it's important not to rely on accurate pulse widths (as neither radio nor IR give those).

 

be80be

Well-Known Member

• Apr 7, 2012

• #5

I'm just after 4 buttons not a lot of data.

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Apr 7, 2012

• #6

be80be said:

I'm just after 4 buttons not a lot of data.

Click to expand...

Manchester coding still makes sense, as it's more reliable - plus the code is there in my tutorials ready.

 

be80be

Well-Known Member

• Apr 7, 2012

• #7

Thanks Nigel I always love your work.

 

be80be

Well-Known Member

• Apr 8, 2012

• #8

It's important not to rely on accurate pulse widths (as neither radio nor IR give those).

Click to expand...

Your right there I tried the keying a 10mS on 10mS off you can tell how long it is first time it gets the rising edge fine but say you use that to start a led blinking it gets out of sync and takes a long time to catch the edge.

I got these with the decoder too but it's fun using the ones with out it. I think a dollar more for decoder was well spent. After all the playing LOL