I realise I'm showing my age and ignorance, but I figured if I didn't ask, then I would remain ignorant.
I recently opened a VCR IR remote, which had stopped working. By means of my digital camera, I worked out it wasn't lighting the IR led. Turns out that the led had become partially detached. (See this small boy, see this sharp pencil, see that broken remote).
Well, while it was open, I thought I'd take a look at how to hack the remote by using an Arduino to press buttons. Except there aren't any switches.
Instead there is a grid-like pattern on the board, and applying pressure makes the contact. Since, when I put it back together it worked, I'm guessing that is HOW it works.
Any advice on how I'd make a break-out (connect to the board) so I could do the same thing with opto-isolators (transistors)?
The PCB doesn't seem to have anywhere sensible for me to start, so I realise it's a long shot....
Hmm. The buttons don't appear to have a conductive pad, at least, not according to my meter. At my age, though, anything is possible.
To hack this, then, I might have to get a little medieval on the board. sigh.
USB microscope later, so there is. I have also identified the encoder chip as well, not to mention finding a datasheet for it, so I should be OK from there!
I did some tinkering with a remote control a long while back (link below). The buttons work in a matrix, something like 6X7, which would give ~42 potentential buttons. One could control this matrix with two 74HC4051 chips. On the remote that I tinkered on I used a multimeter to map the matrix to see how it worked. With careful soldering one can connect to the chip using the exposed pins on the side of the chip.
Small reed relays or similar could also handle that. The problem often is, where to find a good place to solder.
With relays you don't need to know about voltages on the remote. Choose relays well, because signals are small and not enough to go through thick oxide layer on contacts.
If you are lucky, your IR remote use one of the supported protocolls, which is quite a few, but not all of them out there. All is not lost even then, as it can handle the "raw" IR received for unsupported protocolls (unless they are really different, I suppose).
Then you could just wire up an IR LED to the arduino and have it send the commands. I reckon you first would have to have an IR receiver connected to the arduino and have a look at how your remote sends the IR though, and learn what they are.
