PROJECT DEVELOPMENT
I started out with make the main part, the flaps..
TEST 1
Instead of using metal or plastic hinges to connect the flaps, I made living hinges.
Material: MDF
![](images/week 19/mdf cut.jpeg)
3mm MDF turned out to be too thick for easy movement, so I used 1mm cardboard for the second test.
![](images/week 19/cardboardcut.jpeg)
MECHANISM
I designed arms for the movement of flaps and tested it out with different materials and thicknesses.
![](images/week 19/eduboard.jpg)
3d printing with PLA worked the best.
The next issue was with the flaps going back to its original position.
I decided to add a spring that would push the arms to its original position when the spring is released.
I tested the spring out with different materials, thicknesses and designs.
PLA in 1mm, 1.5 and 2mm thickness.
![](images/week 19/testforspring.jpg)
![](images/week 19/pla spring.jpeg)
The prints in PLA turned out to be very brittle.
ASA in 1mm, 1.5 and 2mm thickness.
![](images/week 19/asaspring.jpeg)
Testing a 2 spring system
![](images/week 19/testwith2springs.jpg)
![](images/week 19/failed2spring.jpeg)
![](images/week 19/test2spring3d.jpg)
In theory, 2 springs mirrored and attached at the top and bottom should have kept it in line but that did not work.
So I needed to make housing to keep the spring in line.
![](images/week 19/housing1.jpg)
![](images/week 19/housing 2.jpg)
I also made a pulley in the center with holes that the string from each side can go through and get connected to the servo.
![](images/week 19/pulley.jpeg)
![](images/week 19/pulleysystem.jpg)
DESIGN FOR FINAL PROTOTYPE
- LASER CUTTING
- VINYL CUTTING
- 3D PRINTING
- ELECTRONIC
The flaps are laser cut in 1mm cardboard and the base in 4mm Plywood.
![](images/week 19/lasercut.jpg)
![](images/week 19/laser.jpeg)
The input is a capacitive sensor cut from a copper sticker with a hole in the center to solder the wire in.
![](images/week 19/vinyl.jpeg)
The Springs connected to the arms are printed in ASA, the housing in PLA and the central pulley also in PLA.
![](images/week 19/housing3.jpeg)
![](images/week 19/pulley2.jpeg)
I need to make a PCB with would take input from a capacitive sensor and relay the signal to a servo motor.
![](images/week 19/pcb traces.png)
![](images/week 19/pcb-outline.png)
ARDUINO CODE
![](images/week 19/code1.jpg)
![](images/week 19/code2.jpg )
ASSEMBLY
![](images/week 19/assembly.jpg)
TESTING
I had to experiment with different
- ways of connected the string to the motor.
- Attaching the servo to the base with a laser cut plate/ spacers.
- Different thicknesses of the spring so there is less weight on the servo to pull.
![](images/week 19/fin1.jpeg)
![](images/week 19/fin2.jpeg)
At first, I barely got any movement from the flaps because the springs I used were too thick and were putting a lot of pressure on the servo. So I printed out another set of spring with lesser wall thickness. I still don't have a full range of motion, but I have proof of concept now and I would like to fine tune the mechanism in further iterations.
![](images/week 19/presentation.jpg)
Design files download
Rhino file
Laser cutting dxf
Stl for spring
Stl for pulley
Kicad
Arduino