detecting Sky IR pulses

btemple

New Member
I just need to detect the presence of a "Skye"signal to initiate an action.
It does not matter what button.
Interrupt does not seem to work (the sky signal is a falling waveform).
Pulsin should work but I don't know how to read the pulses.
Can anyone help? By the way, I can see the waveform on my storage scop
 

inglewoodpete

Senior Member
I just need to detect the presence of a "Skye"signal to initiate an action.
It does not matter what button.
Interrupt does not seem to work (the sky signal is a falling waveform).
Pulsin should work but I don't know how to read the pulses.
Can anyone help? By the way, I can see the waveform on my storage scop
I'm afraid you've lost me on this one. I see you're in Scotland and I remember from primary school (over 50 years ago) an island off the coast of Scotland being called "Skye". I've not heard of Skye emitting IR, especially in the middle of winter :).

I imagine you're using a TSOP 38/40kHz IR receiver. Please post a copy of your circuit and your code so far. And, perhaps a summary of the project so forum members have a better chance of helping you.
 

Jeremy Harris

Senior Member
Skye isn't even line-of-sight from Helensburgh, there's a damned great range of mountains in the way, plus it's about 85 miles from the nearest point on Skye to Helensburgh, as the crow flies.

From the description it looks like the pulses may well be fairly rough signals, that may well need some cleaning up before they could be reliably detected. If you can let us see the shape of the waveform we may well be able to take a stab at how best to clean it up into something a Picaxe can decode. There are lots of ways to do this, but without knowing where the waveform is coming from (in terms of the circuitry that is generating it) it's pretty hard to guess how best to tackle this problem. Knowing how often these pulses are received would also help a lot.
 

hippy

Senior Member
I am guessing btemple may be wanting to look for signals from a Sky Satellite Receiver Remote. If so that is possible.

One way to do it is to read in the IR stream straight into a memory buffer then analyse what that buffer full of data represents. The IR Scope software described below does that and also includes details of how it could be used to identify that a Sky Remote code had been received.

I would guess the numbers in the code match what a real Sky Remote would put out because that was what I was probably using. Run the IR Scope software and it will show the numbers obtained which would confirm if that's the case or not.

http://www.picaxeforum.co.uk/showthread.php?26791-IR-Scope
 

MartinM57

Moderator
+1 that OP is trying to detect Sky Satellite TV remote controller signals.

Requirement is for "any key" so no reading into buffer/decoding required - seems that the problem is actually getting anything detected by the PICAXE at all.

If OP can see the pulses on a storage scope, then there must be some sort of receiver already involved, and if the pulses can be seen from it and the signals are 0v/5v then surely they can be detected by a number of means - polling for change, interrupts, pulsin etc.

@OP - more info please - what exactly do you have/have you done/code snippets (failed or otherwise) etc...
 

hippy

Senior Member
Requirement is for "any key" so no reading into buffer/decoding required - seems that the problem is actually getting anything detected by the PICAXE at all.
A simple "is IR present?" test may work but I get the impression that the OP wants to tell when it is an actual Sky remote button pushed rather than the TV or some other remote being pressed. If so that will require some sort of decoding to determine the IR is from the Sky remote.

The IR signal is a falling, active Low, signal out of a TSOP detector and that should be long enough to trigger a SETINT or HINTSETUP interrupt. It may therefore be an issue with the code. It could simply be reading the wrong pin, having the interrupt mask and level swapped round.

More details to confirm what's wanted and what exactly is and isn't working will help members give more assistance.
 

MartinM57

Moderator
Amazing how people make up undocumented requirements ...:)

I'll wait until OP comes back and tells us there's 17 different IR remotes firing off continuously in the vicinity before thinking about a solution to detect (just) the Sky remote :D
 

hippy

Senior Member
From a quick look at my code it seems Sky is a 2700us pulse followed by an 890us gap. That might be enough to identify a Sky IR packet from some other.
 

btemple

New Member
interrupt works!

A simple "is IR present?" test may work but I get the impression that the OP wants to tell when it is an actual Sky remote button pushed rather than the TV or some other remote being pressed. If so that will require some sort of decoding to determine the IR is from the Sky remote.

The IR signal is a falling, active Low, signal out of a TSOP detector and that should be long enough to trigger a SETINT or HINTSETUP interrupt. It may therefore be an issue with the code. It could simply be reading the wrong pin, having the interrupt mask and level swapped round.

More details to confirm what's wanted and what exactly is and isn't working will help members give more assistance.
I am an idiot...yes, I had got the interrupt mask the wrong way round.
And yes, I did not supply enough information The Sky remote TV control uses a 36kHz carrier signal and I was using a TSOP (Vishay).
I also spelled Sky as Skye, which is of course an island quite near to me.
I think setint will do. I have a game for a disabled person who can only, in a controlled fashion, move his head and his eyes . Since I needed three switches for the game, I am going to use his TV signal that he can send from his eye-controlled computer system: it is set to control a Sky tv box.
 
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