week 17 final project (dynamic 'jali')

After long hours of preparation, we finally have been able to produce a working prototype of what we intend the final model to be. While I made all the initial prototypes and the final one with the rivets, Ashris and Ankita helped documenting the entire process.

Sotry board.

First protoype I made was using paper (mill board), cut using laser machine and fixed with revets manually. The height of revets was too high so while fixing them for just two sheets of paper put together, only 1mm thickness, it was too. Extra metal flattened at the back restricted movement. This one was almost fixed prototype. No modules moved.

In the next attempt, I scaled up modules with respect to the correct size and height of revet used. Again the modules were cut in paper using laser cutter.

This time it was one step progress. It made the revets better and modules moved a little. But it was still tight as the size of the hole was exactly same as the size of the revet. Also due to this tight movement, pressure on the connecting modules was high due to which they bent. Feed back to the prototype is to choose stiffer material.

Fourth prototype was then made using PVC sheet. Laser cutting burnt the edges of this but for testing material, it was OK. This time thickness (1.5mm) of material was also chosen carefully and with respect to the same size of revets. This was first successful prototype with respect to the smoothness of motion. However, because the edge components (Rhombus) kept keep getting stuck in the extreme open and closed positions. Due to this in case of forceful motion, connection menmers broke. Therefore, next improvement in the prototype to be made was boundary conditions, edge connections and better fixing then revets.

Finally this each component was cut in 1/8" cast acrylic with laser cutting machine. And instead of using revets, machine screws (Chicago screws) 3mm were tried on one module. To fit the diameter of machine screw (3mm) size of holes in the modules were changed and hence the size. These are all related.

Arrangement of the pieces in the module

Machine screws (locally known as 'album screws' in India) used to fix the pieces.

First movement (Completely closed).

Second movement/Central position (Completely open)

Third movement (Completely closed) again

Seven modules connected together.

Final tile in First movement

Second movement (Open position)

Third movement. After this protoypes were ready, electronics trials began.

To begin with we researched on how to make own circuit. Also tried to twik input devices assignment of FabAcademy to manipulate sound input. Found research paper on similar project but the circuit didnt work following the theoritical explantion using microcontroller and servo motor. Due to limited time after all the tiy outs, I took help of experts (PlayLab) to make it work. Finally it worked with an Arduino board and DC motor.

Hardware: Arduino Duemilanove (Freeduino); L293D Motor Driver (H-bridge PCB); 150 RPM, 12 V DC Motor.
Software: Arduino IDE 1.0.5.
Circuit diagram:

Connection: First connect the red wire from the GND pin of Arduino (red board) to GND pin on the H-bridge PCB (green board).
Next connect green wire from 5 of Arduino to any one pin of IN2 on the H-bridge.
Next connect yellow wire from 6 of Arduino to the other pin of IN2 on the H-bridge.

Connect the motor wires to the screw terminal besides IN2. Polarity won't matter.
Next just connect the Arduino board to the computer via the USB cable. It should blink some lights on the board. Don't worry if drivers aren't installed, we just need the power from the computer.
Finally connect the power jack to the Adapter and switch it on.

//normal forward-backward motion of motor with delay
void setup()

void loop()




Working of the final module with the whole assembly. The above assembly and electronics is only capable of moving one module. Till now this is the resolution achieved on electronics side. To make the movement absolutely smooth and house the electronics components, an acrylic box is made.

I intend to continue this research and find an electronic solution for moving all seven modules at a time. I would also like to add a light strip in the layer behid this milky acrylic base. But this will continue as a research beyond FabAcademy. So far success!