Working Stop Light

I decided for my passion project to create a stop light. I have had my fair share of red lights driving already, so I decided it would be fun to create an infuriating experience for everybody. This project would also allow me to demonstrate my understanding of 3D modeling/printing and electronics. This would overall present a fun challenge and a good finished product.

Supplies

• Laptop to create 3D models
• 3D Printer to print models
• Circuit Playground
• 3 LED 5mm lights
• Wiring
• Soldering Kit

Step 1: 3D Modeling

I was searching online for a while in hopes of finding a small but easily customizable stoplight. After I had spent time searching, I came to the conclusion that it would be a lot easier to make my own models.

I had a vision in my head of wanting to connect a wire through the pole and base to connect the circuit playground to the lights. I achieved this by creating a paper cylinder (not pictured) and measuring the diameter to put it into the 3D model.

I designed the base and pole around the hole, creating the height and length of the parts by sketching them in my notebook. I found that good measurements for a good scale for the parts were:

Square Base: 76.2 mm (length and width) x 28.58 mm (height)

Pole: 31.75 mm (length) x 36.12 (width) x 82.55 mm (height)

Head: The head itself is more complex. It is made up of both an exterior and an interior rectangle. This design is a little more complicated to write out measurements.

The hardest part about designing the models was making sure the holes were aligned and the parts needed for the face of the stop light were right in measurement and style.

Step 2: 3D Printing

The next part was to upload the 3D model into kiri moto and get ready to print the design. The printer said it would take 7 hours so I left it overnight and came the next day to make sure the print printed well

I, unfortunately, don't have an image of the finished print, but all the parts came out decently, just a few imperfections but nothing that would bring damage to the overall product. I was super happy that the print came out perfectly and was ready to move on to the next step that same day.

Step 3: Hot Glue and Soldering

The next step was to find a solid wooden base to attach the base and corresponding pole. I found a recycled piece of wood and sawed it down to a small size. I hot glued the base to the wood first, and then the pole to the base, making sure to align the holes correctly.

The next step was to solder the lights and wires to the circuit playground. I first cut a long strip of wire and ran it through the hole inside the base and pole. I stripped the wire at the bottom to solder the wires to the circuit playground. The wire was then cut to a smaller size a the top and stripped to remove the rubber coating.

After I soldered the wire to the circuit, I moved on to the LEDs. To create the correct spacing for the lights inside the head of the stop light, I flipped the head upside down and placed the lights with their metal wires sticking up, with the corresponding sizes of the legs aligned. I then grabbed the wire that was in the pole and soldered them to the top of the stop light, making sure the corresponding wires were attached to the correct lights. This step allowed for a much easier and more precise process to solder the LEDs to their corresponding wires. I also decided to only use one ground wire for all 3 wires to save space inside the hole and not pack them with wires.

Step 4: Skeleton and Coding

By this point, the wiring and soldering were all finished, so it was time to test to ensure all lights could turn on and be coded appropriately. I connected the circuit playground to the computer and tested all lights. They, fortunately, were all turned on, but there were some issues with wiring I wasn't able to figure out. The wires would work at certain angles and not at others. I believe this was due to my inexperience in soldering and therefore with a little more precision, the stop light would work a lot better.

The coding is up to the user. I decided to opt for a random number generator that has the stop light consistently running, never knowing when the light will turn green, just like in real life. This ended up being a fun decision and worked out really well.

The final step was to hot glue the head and face of the stoplight, and then I was done.

This project was a really fun experience and exploring all the skills I had learned throughout my maker space class. Some things I would like to improve next time are my soldering and maybe adding a design to the stop light since the 3D print has a decent amount of holes and rough terrain.