Sometimes, the ideal little package comes along and you don’t have to do all the hard work fabricating a physical user interace. While working on the Spot-On project at LKL, I found a very nify little “finger torch” that solves the problem of powering up an LED in a small form factor. This little guy’s is perfect for retrofitting with an LD271 infrared emitter, for Wiimote hacking, IR Motion tracking, and generally mucking about moving around infrared sources, for you Johnny Lee fans. This package combines 3 button cells, a switch and an LED into a tight little case with a hook-and-loop strap. Not sure if it’s emitting continuously or in pulses (PWM) but there’s a microcontroller under that resin blob (pic 2), so it seems likely. A little de/re-soldering and, you’ve got yourself a perfect finger-mounted IR pointer!

At Tinker, we’ve been working on some blue glowing balloon clusters for an upcoming event. They consist of a blue LED and an ATTiny13 microcontroller and they pulse with a slow, compelling sine wave. Selecting the timing of the sine wave was an important consideration, but it was necessary to make a choice about the frequency of the wave oscillation before programming the ATTiny microprocessors and inserting them into the balloons. I wrote this little sketch in Processing to get an idea of what a cluster of glowing balloons would look like and used the same sine wave lookup table we generated for the ATTinys.

The code below produces this.

// A program to simulate balloons with LEDs inside.
// Uses a sine wave lookup table rather than
// a sin wave generated by a function.
// Brock Craft, 9 Aug 2008
// at tinker.it

int num= 60; // number of ‘balloons’
Led[] led;

void setup(){

size(300,300);
noStroke();
smooth();
colorMode(HSB);
led=new Led[num];
for (int i=0;i<num;i++){
led[i]=new Led (int(random(width)),int(random(height)),int(random(255)));
}

}

void draw(){
background(53);
for (int i=0;i<num;i++){
led[i].render();
}
}

void mousePressed(){
for (int i=0;i<num;i++){
led[i].x=int(random(width));
led[i].y=int(random(width));
}
}

class Led{

int i;
int x;
int y;
int col;

// mapping the colour intensity to a sinewave that’s in a lookup table below
int map[]={
0,0,0,0,1,1,1,2,2,3,4,5,6,6,8,9,10,11,12,14,15,17,18,20,22,23,25,27,29,
31,33,35,38,40,42,45,47,49,52,54,57,60,62,65,68,71,73,76,79,82,85,88,91,
94,97,100,103,106,109,113,116,119,122,125,128,131,135,138,141,144,147,
150,153,156,159,162,165,168,171,174,177,180,183,186,189,191,194,197,199,
202,204,207,209,212,214,216,218,221,223,225,227,229,231,232,234,236,238,
239,241,242,243,245,246,247,248,249,250,251,252,252,253,253,254,254,255,
255,255,255,255,255,255,255,254,254,253,253,252,252,251,250,249,248,247,
246,245,243,242,241,239,238,236,234,232,231,229,227,225,223,221,218,216,
214,212,209,207,204,202,199,197,194,191,189,186,183,180,177,174,171,168,
165,162,159,156,153,150,147,144,141,138,135,131,128,125,122,119,116,113,
109,106,103,100,97,94,91,88,85,82,79,76,73,71,68,65,62,60,57,54,52,49,
47,45,42,40,38,35,33,31,29,27,25,23,22,20,18,17,15,14,12,11,10,9,8,6,6,
5,4,3,2,2,1,1,1,0,0,0,0
};

Led (int myx, int myy, int mycol){

x=myx;
y=myy;
col=mycol;
i=int(random(255));
}

void render(){
i++;
if (i>=map.length){
i=0;
}
fill(180,map[i],175);
noStroke();
ellipse(x,y,30,30);
}

}

Looks like Ponoko has made it easy to get access to a laser cutter. Check out http://www.ponoko.com/ where you can design objects and have them fabbed and shipped right to your door. You can even sell your designs on their website. Similar to Café Press, but for 3D objects!

My friend Adam Sporka’s been working on some new segment designs in an effort to get the maximum number of readable characters with a minimum of segments. They are pretty novel and the inclusion of curves leads to some very attractive new letterforms:

Check out Adam’s flickr photostream for more: http://www.flickr.com/photos/adam_sporka/1890226576/

I’ve been playing around with representing textual information with 7-segment displays. The nifty thing about 7-segment displays is they are ubiquitous, cheap, and easily addressable with IC chips such as the (mighty) ULN2003a.

In my immediate explorations, I find that the following letters are not possible using a 7-seg:

M, W, V, K , X, Q, Z

This is considering that it is okay to use lowercase letters to “cheat”.

For example, the word “BURNT” could be written :

|_Â | |Â _Â _Â |_
|_| |_| |Â | | |_

I don’t really like the solution for “N”, but at least it works. It’s a shame about the letter “M”, as it has a somewhat high letter frequency! Here’s a chart of the letter frequencies of the 7-segment “orphans” (based on Wikipedia data):

m 2.41%
w 2.36%
v 0.98%
k 0.77%
x 0.15%
q 0.10%
z 0.07%

The next plan is to develop a display that can handle all the letters with as few segments as possible (inspiration from Josh Nimoy). In the meantime, I whomped up a little Processing program to randomly illuminate the various segments of a 7-seg display…click to view the program: