File this post under fun with technology! Earlier this week, Nikki and I went to Coldplay's Tuesday night concert at the United Center here in Chicago. Coldplay puts on an excellent show. They're all around entertainers and one particularly impressive item in this show was the light-up wristbands given to every guest.
When entering the venue, each guest was given a green, white, orange, pink, or blue wristband to wear during the concert. These wristbands are made by Xylobands. Each color could be controlled while the music was playing. For instance, all the blue wristbands would flash while all the orange wristbands stayed on. 20,000+ people all had lights synced to the music. Very cool. Here's a great video from YouTube:
Naturally, I brought my home and took it apart to see how this pulled off. The exit we used did not have any collection bins. Here's a picture of the cover taken off my green wristband:
That's a 3V CR2032 battery sitting on top of the circuit board and here's a shot of the bottom:
Two more 3V batteries are on the bottom of the device (CR2016s) and the wires to the LEDs can clearly be seen. So, there are a total of 9V powering the wristband, which should be good for days. Does it still work and how's they pull off controlling the wristbands?
Taking out and putting the batteries back into the device caused the lights to flash. That's smart. The microcontroller flashes the lights to let the person know the band is ready for action.
Two components are largely responsible for this device working:
A computer chip to read instructions and tell the lights what to do (blink, flash, turn off, stay on, etc...)
A wireless receiver to get those instructions.
Here's a picture showing those two components:
Each chip has text written on it and a bit of Googling shows that they're both from Silicon Labs:
C8051F980 Microcontroller: this holds the brains of the operations. Based on the instructions it gets, it'll control the lights. It'll also flash the lights when it first turns on (i.e. gets power) and then probably starts communicating with the RF receiver. I imagine the device also enters a low power consumption mode after not receiving a signal for a period of time.
Si4313 RF Receiver: these are the ears of the device. This component is used to wirelessly receive instructions. You can see its oscillator just to the left of it in the image.
Hats off to Coldplay for turning the entire venue into the inside of a Christmas tree and to Xylobands for inventing such a neat device!
