Hand tools and fabrication machines
I am fascinated with mechanical displays. From the established split flap displays to newer displays such a flip dots and mechanical 7 segment displays, I have always found watching these displays in the transition phase to be captivating
Apart from the visual aesthetic, I also enjoy the auditory feedback these displays give. The clacking of parts and switches are very pleasing to listen to.
Following Scott Bezek's opensource documentation of his split flap project, I was able to adapt the design to the laser cutters and materials available at Rice. I chose to cut the frame out of clear acrylic sheets to display the interior mechanisms.
One issue I ran into was the size of the opening in front. If the opening is too small, the stepper motor has a hard time rotating the spool. If the opening is too big, the flaps tend to just fall through and also do not make as satisfying of a sound when turning.The text is cut from vinyl sheets. Although I think moving forward, I will experiment with opaque or frosted acrylic as some of the letters are hard to read currently.
All individual pieces are held together with captured M4 nuts and 10 mm M4 bolts. This no glue approach allows the acrylic to stay clean and also add another point of visual interest.Code
Using the Beagle Bone stepper motor library written by Pete Bachant, I was able to successfully control the motors.
My general success with code ended there, I struggled with the code quite a bit. My original plan was to create a 4 module display that would display a user input. However, I was unsuccessful on creating a reliable way to keep track of the current position, next position, and starting position of the spool. Although I will continue to try to work that out, the display is currently only runs on predefined code.
There are three programs I have written using the library. A timer, introduction, and a letter randomizer.Build Order
1. Laser cut acrylic pieces. (The rhino file below is setup for 1/8" acrylic sheets)
2. Assemble frame without the spool
3. Load spool with flaps. (I cut the flaps out of 1/32" acrylic sheets)
4. Connect spool to frame and stepper motor
5. Decide text order and apply text
6. Connect modules (I only have 2 modules but have tested with 4 motors)
A big thank you to Dr. Welsh for helping me throughout this project and allowing me to to learn new and valuable skills.