NEC ('Arduino') remote controls.

[Nigel Goodwin]

I'm still experimenting with IR remotes controls, and programming PIC's to use with them - so as NEC remotes (often listed as 'Arduino' remotes) are dirt cheap (only 22 pence from China), I ordered a few different ones - to go along with the couple of similar ones I already have.

I was shocked to find that the key assignments have no bearing on the labels, and are simply the physical position on the remotes - so the remotes are identical other than the labels on the front. For example, '1' on the black remote is the same code as 'CH-' on the silver remote, '#' is '200+' etc, and '1', '3', '7' and '9' on the silver remote don't even exist on the black remote, as they are the missing corners of the cursor section.

The address code of the remotes is identical as well, and is simply 0x00 - it makes the remotes less useful as replacements, as you've got to ensure you find one with the labels in the right places

On a further shock, the new gaming PC I bought earlier this year has a silly 'flashing light display' inside, and comes with a similar looking remote to alter it, or turn it off (this gets done the instant it's turned ON) - however, while the remote looks identical, it produces no output from a normal TSOP IR receiver, so I've no idea what system it uses. I'll have to get hold of a photo-transistor to see what it's putting out.

 

[hexreader]

I struggled using phototransistors and photodiodes to read IR signals.
The signal shown on scope always seemed very distorted and very low amplitude.

I had more success with Vishay TSMP58000. Similar to TSOPxxxx IR receiver 3-pin, but gives out raw IR at TTL levels, without de-modulating
Limited to the range 20kHz to 60kHz

For absolute best oscilloscope trace, open up the remote and scope directly across IR LED, or perhaps battery - to IR LED

And yes, generic remotes are the wild west of NEC protocol coding - all bets are off

Sony protocol is my favourite protocol - well defined and really easy to decode

 

[For The Popcorn]

Some of those ubiquitous remotes are actually RF. I bought several with controllers for LED strips. As I recall, they mostly put out the same codes for each key position, except for one that seemed dead. Then I noticed the microscopic print that said "RF".

 

[Nigel Goodwin]

Some of those ubiquitous remotes are actually RF. I bought several with controllers for LED strips. As I recall, they mostly put out the same codes for each key position, except for one that seemed dead. Then I noticed the microscopic print that said "RF".

Well, I just had a quick look at the lights remote with my computer - no mention of RF on it, and it has an LED sticking slightly out the front, it looks exactly the same as the other remotes, just with a different label most of the buttons are just colours, to select different colours inside the case.

However, while playing with it, I noticed that the front LED flashes red when you press a button? - so I thought, perhaps it uses visible light, rather than IR?. But as it's obviously just a 'standard' WS2812B controller remote, I googled for them, and found this exact same one. Notice the receiver next to it says "RF remote control", and the Aliexpress page says:

Package included:
1 x LED Controller
1 x 21 Key RF Remote controller (Battery not included)
1 x User Manual

Incredibly, it's priced at only £1.32

So thanks for that, as it looks exactly like the other IR remotes it never occurred to me that it might be RF.

 

[For The Popcorn]

Oh, that's right. I remember being fooled by the LED until I saw it was flashing red.

I don't know how they can sell things so cheap, sometimes even with free shipping!

 

[Nigel Goodwin]

Oh, that's right. I remember being fooled by the LED until I saw it was flashing red.

I don't know how they can sell things so cheap, sometimes even with free shipping!

The free shipping seems to have stopped to the UK now, but it's still pretty cheap.