Toner Transfer Method
- Copper-Clad Board
- Ferric Chloride
- Laser Printer & Transfer Paper
- Scrubber/Steel Wool
Print board design on transfer paper using laser printer & cut out shape. Prepare the copper board by sanding off protective layer with a scrubber or fine steel wool.
Lay the printed circuit design face down on copper and feed thru laminator 5 times (the laminator we used was hacked so it goes through slower and at at a higher temperature). After going through the laminator, drop the plat into a container of water for a few minutes and agitate. When it is ready, the paper will separate from the copper on its own and leave the printed design on the copper.
Cut out the design leaving as little copper on the edge as possible without cutting into the black printed part (less copper = faster etching time). Drop the copper board into container of ferric chloride (with gloves on). Agitating the acid will speed up etching process.
After about 20-30 minutes, the board is ready and we put in water to neutralize acid. Only the copper under the printed design remains while everything else is disolved. Last step is to sand off the toner and drill holes for the components.
Mary Fe, Maria Paula and I finally got our shake on! We learned that it is best to use thin copper wire wound very tightly and many many times to get the most voltage. The best coil we got can put out a max of 10 volts.
We soldered up a board with 6 LEDs, a bridge rectifier and 4 0.0047F capacitors in parallel to hold some of the charge.
Starting voltage: 0 V
Ending voltage: 8.5 V
Capacitance: 4 x 4700 microFarad
Starting energy: 0 joules
end: (0.5) * 4 * (0.0047 F) * (8.5V) * (8.5V)= 0.68 Joules
power = 0.68/ 20 secs = 0.034 watts
The motor I was using is does not put out a lot of voltage so I had to back it up with a lot of capacitors. When there was no load on the circuit, I could charge all the caps up and get a steady flow of 5.2 volts. Once I hooked the arduio up with the LED blink sketch, it was only getting 2.5 to 3.5 volts after the load… so the arduino couldn’t stay on for more than a few micro seconds. :|
Basic Analog Circuit
A game that mixes the interaction of physical and digital objects. It draws influence from games like pinball, pachinko, tetris and wack-a-mole.
The Game: The physical game board has 5 irises staggered at the bottom. The irises will open and close by the use of servos working behind the game board. A processing sketch is projected onto the board with circles in positions corresponding to each iris.
Particles/balls/objects fall from the top. The objective of the game is to catch these objects by opening the irises. To open an iris, the player presses the button on a physical controller, which triggers the servos. Each iris will only stay open for 2 seconds then closes again. If the object hits an open iris, player scores a point (iris lights up/blinks). If it hits a closed iris, it will bounce off and change its vector. At that point, the player still has the chance to catch it by opening one of the irises in the next row. If the object is never caught, it falls off the screen and disappears.
It sounds like a fairly simple game, but because of the timing, it takes quite a bit of skill. Sometimes it is best to catch one in an open iris, but other times it is best to bounce the ball off a closed iris and catch it in an open one.
NOTE: Probably the most popular question I received during the show was “where is the camera?!” The answer: there is no camera! It’s all done in processing using collision detection algorithms! There is really no need for machine vision when I can define the areas of the irises and track positions of objects in Processing.
Design of irises derived from thingiverse http://www.thingiverse.com/thing:31855 adapted for laser cut acrylic.
Arduino & Processing code can be found here!
PDF of all the laser cut parts can be found here!
Team: Xuedi Chen, Andrew Siegler & Tarana Gupta
For more information, see earlier post on development & construction process.
The gears are looking and working A LOT better once i made them out of plexi. I don’t even necessarily need the two side gears anymore to hold it since there isn’t much resistance with this material.
I want to ultimately make the moving parts out of plexi but I made a prototype of one iris structure out of wood (because plexi is expensive!) and tried to hook it up to a servo. While the mechanism works by hand, albeit roughly, it does not work so well with the servo because of several reasons. 1. Material has a lot of friction. 2. The tolerances of the track on which it rotates needs to be tightened up a bit to decrease side to side movement. 3. The screws may be adding some extra friction from the threading.
By popular demand, I am posting directions here so everyone can make one! The star projector works like a pinhole device so if you add more lights inside, there will be more “stars”. BE ÜBER CAREFUL! These LEDs are really bright, if you stare straight at them, you will most definitely get a headache for a few hours.
Step 1: Materials
- 2 sheets of 12 x 20 black museum board or something comparable. I got a 20 x 30 sheet at blick for around $4.
- A battery pack from Radioshack that hold 4 AA batteries. (total output 6V)
- 1 (or 2) super bright LEDs. I used two of these https://www.sparkfun.com/products/9658? (They are rated for about 3.15 to 3.99V and max 700mA)
- Since these LEDs draw a lot of current, be sure to make a bundle of resistors in parallel to handle the current, or else things might catch on fire. One bundle of resistors for each LED. I used three 470ohm resistors plus one 4.7ohm. (you want something low around 4.7ohms as the resulting total value. Use any combination, just make sure your math is right.)
- Optional – (If you want it to spin) A pretty torque-y dc motor with some kinda platform for the thing to sit on. I ran it at 3.3V, off of an independent power source.
Step 2: Laser cut the thing!
- File can be found HERE!
- Cut the red lines & score the black lines.
- Good cut settings for museum board (20, 75, 500)
- Good score settings (50, 45, 500)
- After you cut, you’ll have to poke out the circles with something tiny and sharp.
Step 3: Build the thing!
- Fold along all the score lines slightly, you’ll start to see the shape immediately.
- One tip: peel off half the layer of the scored tabs, it’ll make the whole shape fit a lot better when you get to gluing.
- Get to glueing! I used hot glue for a quick fix. You can also use krazy glue of you want, just something fast drying.
- When glueing the second half of the thing, leave one of the panels open without glue so you can get the LEDs in.
- Wire up the LEDs and resistors and stick them in.
- Wire up the motor and make it spin!
This is a super fast hack job. Customize it yourself. Add a switch on the outside so you don’t have to open the thing up every time to turn it on and off, whatever you want. Have fun!
I’ve been wrecking my tired mushy brain for weeks thinking about a fun and interesting project to do for a final project. I became very fascinated with this iris mechanism (pic below), which I first saw a print of at Maker Faire this year. The way it moves is so simple and elegant, so I decided to incorporate it. At first I imagined a field of these reacting to some external stimulus. While it may not be hard to physically build 50 of these, programming them would probably pose a huge problem I’m not sure I’m ready to tackle on my own. So I scaled back…
The Idea So Far…
I’m imagining an infinit game with a physical board and processing projection. The vertical game board will have 10 of these irises staggered at the bottom. The irises will open and close by the use of servos working behind the game board. A processing sketch will be projected onto the board with circles/buttons in positions corresponding to each iris.
Particles/balls/objects will fall from the top. The objective of the game is to catch these objects by opening the irises. To open an iris, the player presses the button in processing, which triggers the servos. Each iris will only stay open for 3 seconds then closes again. If the object hits an open iris, player scores a point (iris lights up/blinks and the button in processing blinks). If it hits a closed iris, it will bounce off and change its vector. At that point, the player still has the chance to catch it by opening one of the irises in the next row. If the object is never caught, it falls off the screen and disappears.
It’s a simple idea right now, not fully developed yet, but sounds like fun.
Another idea I was toying with is working with the Magic Ball. I thought about actuating maybe 3 large ones (made of mylar) with muscle wires and installing LEDs inside them. Maybe it would react to external stimulus or also to a processing projection. The end mood would be like an organism that breathes (by movement of muscle wire and dimming of LEDs) or grows and shrinks depending on how many processing particles is being fed to it. Also, half baked idea so far.