Champaign-Urbana Community Fab Lab
Champaign-Urbana Community Fab Lab

Iteration assignment – Andrew Sun

For this iteration assignment, I decided to upgrade my original Arduino project (see here: http://cucfablab.org/arduino-intro-andrew-sun/) into an actual lockable box, using the laser cutter and a servo.

Here is the original “lock” that I made:

Original idea for the box design:

 

To begin, I used the BoxMaker software to create a basic design that I could modify. I wanted to have a liftable lid on a hinge, so I removed all of the notches which belonged to the top of the box, and added a hole to insert the lid into, along with holes where the LEDs and joystick would stick out. The diagram was quite confusing, since some pieces were flipped in the design – I nearly put the hole on one of the pieces on the wrong side. I ended up cutting out a sheet of paper to visualize how all of the pieces would fit together, before using the laser cutter.


Now I have a box and a l- wait, oops! I forgot to account for the width of the wood, so the hinge didn’t fit into the holes I created. Additionally, I didn’t account for the the wood around the holes, so the lid would have fallen into the box if I just made the lid narrower. I solved this by adding a notch around the hinge, to let it rotate around the hole while keeping the rest of the lid wide enough to cover the entire box.

To create the locking mechanism, I decided to use a latch, with one piece of wood attached to the servo, and another attached to the box. When the servo rotated to 90 degrees, the piece on the servo would move under the piece on the box, which prevented the lid from opening. I had to play around with the position of the pieces to prevent the servo from getting stuck. It helped to use a pencil to mark the position of the pieces, so that I could test various combinations without having to actually glue the pieces together.

Finally, it was time to integrate the Arduino circuit with the lid. Previously, I had used jumper wires to create the circuit; but I found that they would often get stuck under the lid and took up a lot of space within the box. I replaced them with some insulated wire, which I cut to the right length so that it wouldn’t stick up. Unfortunately I didn’t have wire strippers, so I ended up using a pair of scissors to cut off the insulation at the ends, which took a really long time! I couldn’t get rid of the jumper wires attached to the joystick, since the joystick only had male connectors. If I had some extra time, I could have tried soldering the wire to the connectors. My updated code is available here: https://ghostbin.com/paste/j4xwh

Demo of the finished product: