Friday, March 14, 2014

The Remote Project - The Specifications

Currently on my coffee table I have:
  • A wireless keyboard (to control a Raspberry Pi)
  • A TV remote
  • A digital tuner remote
  • An AV Receiver remote (with the volume buttons no longer working)
  • A DVD remote
I hate it... I really hate feeling a tiny bit guilty because I can't be bothered turning off EVERYTHING... that'd take too many remotes... For the Raspberry Pi I'm considering a opto-isolator to be able to turn it off and on remotely.
Sound at all familiar? I was looking for a replacement to the AV Receiver remote when I thought to myself "this is silly". For the price of a replacement, I could potentially get rid of all of the remotes on the coffee table and get it down to just one.

Now you probably think I'm thinking of a universal remote. I've had a play and I hate them. I mean, there are probably some really cool ones out there but I doubt any of them could replace the keyboard for the Raspberry Pi.

And there's always the phone option... but then smart phones aren't great for battery life. So chances are, if I'm sitting down watching TV, the phones on the other side of the room charging. Besides which, this brings it's own problems. For example, I'd have to show everyone else how to use their phone to control all of the devices (inserting an IR blaster, putting the volume up, designing an app and putting in remote codes).

So it'd be real nice to just have a really simple remote that could just sit on the coffee table and do what it needs to do (and I'm damned if I'm going to buy a cellphone/tablet just for this purpose).

I got to thinking...

I could control the Raspberry Pi with an Arduino Leonardo receiving signals from a remote control. I've got one sitting around that cost me around $12 (off ebay. It's a mini). A Leonardo can tell a computer that it's a keyboard so... it just seems way too easy.

For the remote itself I'd need a bunch of buttons. Around $2 for 100 off ebay.

I'd need something that both communicate with the Leonardo AND send out infrared signals... for which an Arduino mini seems ideal. (also lying around - $5).

This is where my design has gotten a little silly. I wanted a way for the remote to communicate with the Leonardo controlling the Raspberry Pi. In which case, transceivers all around! I could have just used an IR (Infra Red) receiver on the Leonardo though cost wise, they're much a muchness (except that I still had to buy an IR receiver to be able to record signals from the existing remotes). So $2 for 2 transceivers and $1.90 for the IR receiver (it was cheaper to buy one from China with free shipping than it was to go to the local electronics store to get one).

I toyed with the idea of printing up my own PCB though I really wasn't keen. It would have been kind of cool but I REALLY hate working with chemicals that I have to be cautious of. I've had a few vero strip boards lying around for ages which I figured will have to do.

It's worth noting I'm actually not that much of an electronics guy. While I see other people talking about ... stuff... power rectifiers and stuff.... All I really want to do is come up with something that does something useful and I understand (not for the sake of understanding but rather to accomplish something).

So from my initial costings... (knowing full well I'm probably going to have to get a few more bits and pieces)...


Cost (NZD)

Arduino Leonardo (1)12.00
Arduino Mini (1)5.00
Momentary micro buttons (25)0.50
Vero Strip Board (1)1.10
Arduino Transceivers (2)2.00
IR Receiver (1)1.90
Diodes (I'll explain later) (25)0.27
IR LED (1)0.01
Total $22.78

That total's looking brilliant at this stage given that a replace remote for the AV receiver was going to cost at least a tiny bit shy of $50.

In my next post on this subject I'll go over the buttons... (A button matrix and designing it for the vero board).

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