careless whispers….

So we everything came together. Unfortunately, we’re getting weird values from our photocells…Or they just may not be sensitive enough to record values inside the camera. This means we won’t be creating images any time soon. What we do have is:

1) A well designed, light proof housing.
2) A working XY plotter, with perfectly functioning IRs
3) A 16 cell pcell CCD with ethernet wiring.
4) Working Software.
5) The Best Team in the World
6) A strong desire to get this thing running and working
7) A project that we all love
A new found sense of confidence….

We have learned so much. Our goals were lofty, and I think we’re close to meeting them We have worked incredibly hard. I know we have alot to improve, but I am so proud of what we’ve already done.

I know we’ll get this. And I’ll keep you posted about it.

here are some pics of the “finished” housing and rig:

The software for the pinhole painter involves both arduino and processing. 18 sensor values (the 16 photocells from the MUX, along with values from the two IRs) are sent to processing via serial, parsed into pieces, and then plugged into arrays which transfer the photocell values into corresponding greyscales. The greyscales are then “painted” along the screen.

In order to ensure accuracy, the IR values are averaged in arduino before being sent to processing.

//ARDUINO CODE — ASCII SENDER
int val[16];
int analog1[5];
int h, j;
long average1;
int analog2[5];
int p, q;
long average2;

int a= 3; // SELECT PIN A0 GOING INTO PIN 2
int b= 4; // SELECT PIN A1 GOING INTO PIN 3
int c= 5; // SELECT PIN A2 GOING INTO PIN 4
int d= 6; // SELECT PIN A3 GOING INTO PIN 5
//we are using three analog pins
int analog0 = 0;
//int analog1 = 0;
//int analog2 = 0;

void setup() {
Serial.begin(9600);
pinMode(analog0, INPUT);
pinMode(a,OUTPUT);
pinMode(b,OUTPUT);
pinMode(c,OUTPUT);
pinMode(d,OUTPUT);
//pinMode(analog1, INPUT);
//pinMode(analog2, INPUT);
}

void loop() {

for (int i = 0; i > 1) ;
// shift value 2 bits to the right, and mask all but bit 0:
int pinThree = 1 & (i >> 2);
// shift value 3 bits to the right, and mask all but bit 0:
int pinFour = 1 & (i >> 3);

// set the address pins:
digitalWrite(a,pinOne);
digitalWrite(b,pinTwo);
digitalWrite(c,pinThree);
digitalWrite(d,pinFour);

// read the analog input and store it in the value array:
val[i] = analogRead(analog0);

//val[i] = i;
Serial.print(val[i], DEC);
if (i

Got the new, IMPROVED, 16 photocell ccd up and mounted. After massive wiring issues with the first cell (too many wires that weren’t flexible enough to allow movement), we gave the cells a common power source, and wired their outputs with ethernet cable. The result was much tidier, though I am a little freaked out by the fact that all the cells are now linked…much harder to deal with this way on the technical side, but this improvement should result in a more user friendly experience.

As i was somewhat concerned about building a completely lightproof box with our rather wonky shop tools, we decided to purchase a wooden record cube and outfit it to our needs. The cube itself was well constructed, but still ahd some light leaks along it’s seems. To combat this, every interior seem of the box was covered several times with black masking tape. In order to make changing the pinhol easy on this beast, I epoxied four bolts to the front of the camera, and made interchangable pinhole plates, and a light proof gasket of duvatene to ensure no leakage between the camera body and the plate itself.

in the end, a brass handle was added for portability.

After some testing, we decided to use SHARP GPD2D120 IR rangefinders to locate the CCD and moving handle in space, and then translate their values to processing. These sensors are ideal: They are capable of accurately sensing distances from 1.5 inches from the senders head, to about a foot from the sensor. We experiemnted early on with Maxbotix Ultrasonics, but found that they had a dead spot o about 1.5 FEET from the sensor to where it first began accurately ranging.

Check out Acroname Robotics for more info on sharp rangefinders, as well as other types of sensors.

Here are some shots of our sensor placement on the XY rig. It was imperative to position them in such a way that they would see nothing but the head movement, as well as to give them enough room to function properly.

So I know that it’s been a while since I wrote about the Pinhole Painter, and that the project was present as a final last week, but there a few things I would like to briefly touch upon, as they almost killed me.

For all of you with an interest in building an XY plotter rig, my first piece of advice is simple:

Don’t.

For all of you who are insistant on this, I would suggest using incredibly accurate, well maintained tools….Which we most certainly DO NOT HAVE in the ITP shop. Our drill press’ head wobbles, our arm saw cuts at 85% angles, and the band saw, the only piece of equipment in that room that can be remotely trusted, is usually so damn dull you get burn marks on your wood before it actually cuts anything. I could prattle on about this for quite some time, but lets talk about our rig.

I started off with some wood, some brass rod, and a little bit of over confidence.
After a about a week of being continually kicked in the crotch, I ended up with this:

This guy was constructed from two tile cutters, and I constructed the middle rig out of wood and brass. The tile cutters were tools we could easily strip apart and use, very easy to adapt their rails to our purposes. The middle slider, which moves on rails, much like a brio train, works quite nicely. The only issue was that this thing was WAY to damn big. In the end, I abandoned it in hopes of build ing a new, smaller plotter. I will hang on to the big boy, however, as it could easily be used in a number of other projects.

Our final, smaller XY rig was completely hand constructed. By using rails and notches rather then full tubes, I was able to deal with inaccuracy, and still get a working product. This will be outfitted with two sharp IR sensors to locate the rig in space.

Take a Look. Amanda is the best.

Flash is Hard. Tymm and I had some issues, but we made this, and I like it alot.

Click Here