Cardboard Box Diffuser for Photogrammetry/resin Curing

Within my creative practice and lifestyle, I try to find ways to extend the second life of waste objects. I was inspired by the form of this carboard box that I was holding onto for too long. The shape of it seemed perfect for a diffuser box, so why not add a rotating platter and try some photogrammetry scans? Then I thought I could use the same hardware and just swap the LEDs for blacklights and use it as a resin curing machine for 3d prints as well. Lets give it a try.

Supplies

Cardboard box (mine was 9.5x9.5x26 in) , stepper motor (28BYJ-48) and driver (ULN2003), arduino (I'll be using nano), wire, 12v white/warm led strip, 12v blacklight led strip, x2 power jacks, box cutter, scissors, hot glue, soldering iron, solder, CheapStepper library

(i)phone apps (trnio and autocamphoto) These apps were free when I first downloaded them.

You could also use an old turntable, music box, or other motor for the platter.

Step 1: Find and Prepare Box

Find a nice box that is wide enough to fit your platter (mine is about the size of a CD) and tall enough to fit the objects you will be scanning. My box is 9.5x9.5x26 in. Cut a decently sized hole in the box for easy access to where the platter will be. It needs to be big enough to fit your objects and provide a decent view from the camera (my phone). My box already came with some weird cuts in it that seemed perfect for the project.

Step 2: Platter Wiring and Code

For the platter, I will be using a stepper motor, driver, and arduino nano. The cheapstepper library by tyhenry is pretty easy to follow and implement. We will just simplify the simple sketch, so it only rotates one direction and add a delay to allow the camera to take a decent still shot. Follow the wiring diagram (from tyhenry's github) for connecting the motor, driver, and arduino board. In my case, I connected the power input for the motor driver directly to the arduino, so it is more self-contained.

To install the library, in arduino go to Tools>Manage Libraries, search "cheapstepper" and install the library by Tyler Henry.

Then you can go to Examples>Cheapstepper>cheapstepper_simple to load the simple sketch. We can simplify the sketch further rotating one direction and adding a delay to allow the camera to take a shot. I have set it to rotate 10 degrees at a time, but you can tweek this to your liking.

/*
 * cheapStepper_simple.ino
 * ///////////////////////////////////////////
 * using CheapStepper Arduino library v.0.2.0
 * created by Tyler Henry, 7/2016
 * ///////////////////////////////////////////
 * 
 * 
 * //////////////////////////////////////////////////////
 */

// first, include the library :)

#include <CheapStepper.h>

CheapStepper stepper;
// here we declare our stepper using default pins:
// arduino pin <--> pins on ULN2003 board:
// 8 <--> IN1
// 9 <--> IN2
// 10 <--> IN3
// 11 <--> IN4

// let's create a boolean variable to save the direction of our rotation

boolean moveClockwise = true;

void setup() {
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop() {
    stepper.moveDegrees(moveClockwise, 10);
    delay(1500);
    digitalWrite(LED_BUILTIN, HIGH);
    delay(1500);
    digitalWrite(LED_BUILTIN, LOW);
}<br>

This should make the motor rotate clockwise 10 degrees and blink the onboard LED, and repeat.

Step 3: Platter Construction.

Now that we have a rotating motor, we need to add a flat surface on which to place our objects. For this I used cardboard and a CD as a stencil. Mark the center of the circle and cut the cardboard out in the shape of the disc (you may need two layers of cardboard to raise the platter above the stepper shaft so it is level). Then poke a hole in the center mark of the circle using something pokey (used a pencil). Careful not to make the hole too big. We want it to fit snugly over the shaft. Secure with some hot glue if necessary.

Now we have a nice rotating platter ready for our box. I added a grid to the top for more contrast.

Step 4: Installing LEDs and Platter

This part is pretty simple. Just cut two strands of white leds and wire them together on one side with enough room to stick them to adjacent walls of the box without getting pulled off. Wire the other side of one strand to a power jack, and poke a hole near the bottom of the box to expose the jack. Place strands vertically along the walls opposite the camera window you cut in the box. Make sure the wires connecting the strands together are at the top and out of view of the camera. Repeat the process with blacklight LEDs, so you have one jack for white, one jack for blacklight. Then cover them with some more packaging to diffuse the lights.

Test the lights by plugging in your 12v power supply into both jacks. One should turn on the white lights, the other should turn on the blacklights.

Center your platter inside the box and secure it to the bottom of the box with double sided tape or hot glue.

Step 5: Scan

Now we are ready to do our first scan. I will be using a phone app called "autocamphoto" to automatically take pictures at a specified interval and another app called "Trnio" to process the photos (both apps were free when I downloaded them). (You could alternatively take photos manually, or rig up a vactrol trigger system to trigger your camera via 1/8in. cable when the arduino blinks.)

Plug in the white leds, place your object, and plug in the arduino, and set your camera interval (based on your delay). It should start rotating and taking pictures automatically. A tripod comes in handy here (you can make one out of cardboard!).

Once you have enough pictures from enough angles, you can upload them to the trnio app using the photo import option.

After some time processing, you should be left with a 3d model generated from your scans.

https://skfb.ly/onwGw

Step 6: Cure

Now that we have scanning out of the way. Lets explore how we can use the same box as a resin curing machine. We already have our rotating platter and blacklight LEDs, so we just need to place our cleaned resin print on the platter, plug in the blacklights, and start the motor rotation. You can probably remove the diffuser for this part. I think direct uv light is better for curing, but I could be wrong. Not sure of best time for curing so you'll have to test. 5-10 min should be good.

Thanks for taking the time to read through my first tutorial! Feel free to leave some feedback or questions.