Tuesday, April 24, 2012

The Music Container – Part 2

I’ve been able to put more hours on the project and I’m getting very excited with it. I’ve been finding some similar projects on the web but most of them just play a song when the RFID tag has been read, or they’re using flat cards to read them. Most of them seem to be just explorations on how to implement RFID with Arduino, not that much of an exploration of the user experience… I really want to thank all of the guys doing this kind of projects for now I really know what’s happening here.

So, following with my Tinkerlab project: I'm back to business as I finally got some components: an Arduino UNO, the ID-12 reader, some 125KHz RFID tags and the USB base for the ID-12, all from Sparkfun.


The first thing I did was just plugging the USB reader to my laptop and playing around with the tags to see if I had bought the right type, and fortunately for me, I did (I had surfed way too fast on the Sparkfun website, so I was kind of afraid that I had bought the wrong ones). Then I hooked it up to the arduino and wrote some code based on what Martijn The did with BARRAGAN’s code.

The interaction between components is super simple. The ID-12 reads the tag and sends an ASCII code to the Arduino via the software serial. The arduino checks if the code is complete and translates it to HEX numbers, storing it in an array. Then it just looks for tag id in a database and if it exists, pulls the playlist name from another table in the database… Ok, it may not sound that simple, but believe me, it is. I’ll upload my code as soon as I finish tweaking it and spend some time cleaning it to make it usable for others (you), meanwhile, here’s a [very] simplified diagram.

The next step was making some foam spheres to prototype the music containers (I want to make the final ones out of wood, if I have the time, obviously), to see if the tags could be read from 1.5inches away. I used high density foam that I scavenged from the scrap box of the Polaris project I’m also working in, and then had some fun with the ID fellows using the lathe in the woodshop.

Some pics of the process

I split the spheres in half, drilled by hand holes just deep enough to hold the RFID buttons and double-side taped them together again. Some sanding was needed to get the final shape and it also helped me relax after a hard week.

The final RFID’d spheres were tested to see if the tags were powerful enough, and voilá! I’m one step closer :D

Trying the RFID functionality of the first 3 container prototypes

My next steps will be spray painting the containers to start getting some user feedback. Then I'll start working on the code to make it work as I want and make it run VLC and open a different playlist with each tag. I want to be able to edit the tag and playlist database without needing to modify the Arduino code and re-flash the Arduino. I will also work on the base, as I need to hack and tinker with an old mouse and be able to read it with the Arduino (for the playback controls). I also want to get rid of that annoying beep that is kind of driving crazy all of my surrounding peers, so I’ll need to solder the ID-12 to a breakout board and wire it the right way. It seems that I’ll also need to re-think the shape of the containers, maybe making them assymetrical, this just because the RFID buttons only work when they are flat and paralell to the reader… or I’ll need to buy another kind of RFID tag.

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