Picked up a kit the other day on Ebay for about 3 quid, comes with a remote (meant for an in-car MP3, a little circuit board (not needed), and the 3-pin IC I mention. There's already Arduino libraries to read it. 

The same thing was used a few years ago by people with PCs, pretty sure they just connected the IC up to a serial or parallel port (either), and polled with software. By using the CTS line on the serial port, they had a single bit that could switch arbitrarily. Project was called LIRC / WinLIRC I think. Available for Linux, so maybe the Pi would be amenable to that.

Was UK based, postage I think free, and took a couple of days to get here. Saves a USB port and the software's already there! The Arduino version returns a several-digit hex number, I bet the Linux version has options for the same.

There's tons of stuff on the web about using them. The IC is an 1838, available with all sorts of different 3-letter prefixes. It's the standard chip for these sorts of shenanigans.

For the transmitter end, just an IR led modulated appropriately, there's lots of "PC universal remote" stuff available for that too.

Actually, not to tell you how to make your project, but an Arduino for the realtime stuff might be a good addition. Again, 3 quid on Ebay, UK stock. Also has DACs if you wanted to use a cheaper touch screen. 

Also instead of the U/D/L/R buttons, maybe a joystick? The little analogue ones they sell (for about 3 quid!). An aesthetic choice, up to you. They usually have a push-in click, you could use for "ok" in an icon-based setup.

Still waiting on some bits for a little Arduino LED project I'm making myself.

have a look at Stefan lochbrunners pro trinket keyboard mate - 8 buttons, 4 encoders and some onboard rgb LEDs. May well be worth having a look at it :-)

Ta! Might have a look at his code... There's already a library for the ring of WS2812 LEDs. It's great, this Arduino lark! 

Actually it'll probably be useful if I run into problems, I've got the basic idea of what I want and how to do it in my head, and most of the components, just need to get the pad of paper out. The programming's well within my capability.

Power consumption's another thing, I thought it'd be easiest to run it off 9V worth of AA batteries. But kids don't remember to turn stuff off. So maybe a relay or transistor in the power feed, with a push button that bypasses it to enable it to switch on in the first place, then a standard I/O line to keep it on / turn it off. 

Ta! Might have a look at his code... There's already a library for the ring of WS2812 LEDs. It's great, this Arduino lark! 

Actually it'll probably be useful if I run into problems, I've got the basic idea of what I want and how to do it in my head, and most of the components, just need to get the pad of paper out. The programming's well within my capability.

Power consumption's another thing, I thought it'd be easiest to run it off 9V worth of AA batteries. But kids don't remember to turn stuff off. So maybe a relay or transistor in the power feed, with a push button that bypasses it to enable it to switch on in the first place, then a standard I/O line to keep it on / turn it off. 

Thanks for the tipoff mate! I'm currently rehashing this project in my head and will be updating very soon :)

Your tip for a remote is definitely in, and I am going to drop the idea for buttons on the front as such; the enclosure is going to be more of a prism shape so going to add two panels o buttons on the back panel to be used as shoulder buttons.

The panels I am going to use have many buttons, so the outer ones (on the shoulder) will provide shortcuts and the rest will allow changes to the led backlight I'm going to have.

The panels have their own Arduino Pro Micro on so I will have plenty of pins left to tap into.

As soon as I have a case designed I'm sure it'll make more sense ha ha

Ah, I'm ordering a button panel myself, 16 little buttons. A friends kid is mad on pressing buttons. Even when he's playing with a stick, it has imaginary buttons on it. He's not allowed to use the remote control for the TV (he's 3), but you can't keep him away from it when he's feeling sneaky. 

So I thought make something with loads of buttons to press. Got one of those smart LED rings, bung an Arduino in, a few extra LEDs and a buzzer, and it should keep him occupied. I was originally thinking of using an IR remote, but I dunno if his mum wants him getting into bad habits, or making existing ones worse! The option's still there though. 

When I was 3, my grandad made me a "burglar alarm" as I called it. Was a big piece of pegboard, with loads of holes, a battery, a bell, and some jumper wires with banana plugs on the end. Maybe it had some other stuff too. Couldn't get me away from it! I used to love sticking wires in like I knew what I was doing, sometimes the bell would ring. Can't remember exactly, long time ago! Some of us are born geeks.

Ah, I'm ordering a button panel myself, 16 little buttons. A friends kid is mad on pressing buttons. Even when he's playing with a stick, it has imaginary buttons on it. He's not allowed to use the remote control for the TV (he's 3), but you can't keep him away from it when he's feeling sneaky. 

So I thought make something with loads of buttons to press. Got one of those smart LED rings, bung an Arduino in, a few extra LEDs and a buzzer, and it should keep him occupied. I was originally thinking of using an IR remote, but I dunno if his mum wants him getting into bad habits, or making existing ones worse! The option's still there though. 

When I was 3, my grandad made me a "burglar alarm" as I called it. Was a big piece of pegboard, with loads of holes, a battery, a bell, and some jumper wires with banana plugs on the end. Maybe it had some other stuff too. Couldn't get me away from it! I used to love sticking wires in like I knew what I was doing, sometimes the bell would ring. Can't remember exactly, long time ago! Some of us are born geeks.

Re that IR stuff... it's a PAIN in the ARSE! There appears only to be one library available for IR receiving on the Arduino. It takes 10K, out of the 16K I have available... and you don't get repeatable results, the same button can give different outputs, semi-randomly.

You could just check for the code you want. But the controls seem to send all FFs for "button held down". So you'd end up needing the user to press several times, the unit missing loads of inputs.

If you fancy doing it yourself from scratch, feel free like. So maybe the USB is a better option. Sorry about that man! I didn't realise what a catastrophe IR was on the 'weeno.

I could write my own one, but it involves writing an interrupt handler and microsecond timing, not got that far with things yet. 

Just another thought... while you're implementing that, perhaps add an IR LED. Either do the 40KHz modulation with a simple oscillator, or do it in software. Hardware would probably be more reliable, since the Pi doesn't do realtime, especially not when decoding video I should think.

Then, since you've already got a way of reading IR remotes, you could emulate one! Switch your kid's TV to the right input, or control CD players or whatever else through the IR. A universal remote built into the project.

If messing with an oscillator is too much of a pain (without a 'scope or frequency counter, although maybe the Pi could be pressed into service temporarily to do that too), you could maybe use an Arduino or the like to do the IR reading and sending. Since they're dirt-cheap, and realtime. Communicate through a UART to the Pi. Typically an IR remote will repeat the code it sends 3 times, as a simple method of providing redundancy.

However you do it's up to you, but for the price of an IR LED and a transistor to drive it, seems like a useful feature. On top of all the others! 

There's circuits online for IR remote repeaters, meant to send the signal down a wire to another room, where the IR beams don't reach. Since they're essentially just a receiver + transmitter, split it down the middle and there's your circuit.

Thanks man, great idea! My son has an RGB lightbulb in his room that comes with a remote that I was thinking about controlling but hadnt worled out how. That will be awesome@ :)

Ah, self-dimming lights for when he's watching a film. Or "epileptron disco" mode! You can add new gadgets as needed. 

Just another thought... while you're implementing that, perhaps add an IR LED. Either do the 40KHz modulation with a simple oscillator, or do it in software. Hardware would probably be more reliable, since the Pi doesn't do realtime, especially not when decoding video I should think.

Then, since you've already got a way of reading IR remotes, you could emulate one! Switch your kid's TV to the right input, or control CD players or whatever else through the IR. A universal remote built into the project.

If messing with an oscillator is too much of a pain (without a 'scope or frequency counter, although maybe the Pi could be pressed into service temporarily to do that too), you could maybe use an Arduino or the like to do the IR reading and sending. Since they're dirt-cheap, and realtime. Communicate through a UART to the Pi. Typically an IR remote will repeat the code it sends 3 times, as a simple method of providing redundancy.

However you do it's up to you, but for the price of an IR LED and a transistor to drive it, seems like a useful feature. On top of all the others! 

There's circuits online for IR remote repeaters, meant to send the signal down a wire to another room, where the IR beams don't reach. Since they're essentially just a receiver + transmitter, split it down the middle and there's your circuit.

Actually going by your idiom (couldn't find you using "colour" anywhere) you sound like you're nearer to a pound shop than a dollar store. 

Correct - excellent deduction sir! :)

A thought... You can buy universal remote controls from pound shops ("dollar stores", translated trans-atlantic). Not the learning kind, just the kind that have lots of pre-programmed commands.

There also exists, little 3-pin ICs that look like phototransistors. Inside they contain a phototransistor (!), and demodulation circuitry. They demodulate and amplify the 40KHz infra-red that nearly all IR remote controls use. The output is simply pulses, on-off, whatever was transmitted from the IR remote at 40KHz to start with. No decoding is done, you do that yourself in software.

You could connect one to a GPIO. If you don't have an oscilloscope, use the Pi to study what pulses come from a particular remote. Either pound-shop, or maybe some old thing you have lying around from a broken DVD player. In fact there's already software available to support this, for the various Ras Pi media player projects. You might not need to write the software yourself. Although in theory it shouldn't be too hard to do. Doesn't seem like a complex system, although I confess I've never tried doing it myself. Plenty of others have though! Lots of experiments online with IR this 'n' that.

Typically there's a couple of start bits, perhaps a few address bits, then some data bits representing the button pressed. There's no industry standards, but in practice there's only 4 or 5 schemes used in the wild.

That'd be a cheap way of providing a user interface, and the remote could be easily replaced if lost. And of course, remote control! It's just not civilised to enjoy entertainment without it.

Anyway... interesting project!

Thanks for your ideas, greenaum - remote control was on the list of optional features to look into adding once the main functions had been added. I have seen a fair few projects using the exact method you have described, but I have a few USB IR remotes for the pi and was going to use one of them. Your suggestion is a much more useful way of doing it without wasting a USB port.

Thanks matey!