LED Star Projector

High school students will reuse an old aluminum can and learn how to solder to create their own LED light star projector with a 3D-printed base! This tutorial assumes knowledge of how to 3D print STL files, as well as basic SOLIDWORKS skills.

Objectives:

1. Students will create their own base and rod using SOLIDWORKS and then 3D print their models
2. Students will be able to successfully solder cables and LED light strips together
3. Students will be able to assemble all components together to complete a finished product.

STELS:

STEL-1C: Demonstrate that creating can be done by anyone

Students will show that this can be completed by anyone who has a basic understanding of the programs used to create a product.

STEL-2B:  Safely use tools to complete tasks

Students will be able to safely use tools to complete a task

TEP-2: Creativity

Students will use their own creativity to place their own "stars" and create their own constellations

TEP-3: Making and Doing

Students will create a physical product using hands-on methods such as soldering and creating holes.

TEC-1: Computation, Automation, Artificial Intelligence, and Robotics

Students will use Robotics and automation to 3D print their model

LED light strip

USB power cable

Aluminum can

3D Printer

Drill with 1/16 inch bit (or thumbtack but the drill will be much easier and faster)

Wire strippers or pliers

Hot glue gun

Electrical tape

Can Opener

Sand Paper (recommend 80 or 120 grit)

Masking Tape

If you need a crash course or just a video to brush up on soldering just click the link below

https://www.youtube.com/watch?v=Qps9woUGkvI

The Link below will show some quick tips for 3d printing if you need it

https://www.youtube.com/watch?v=YPAXeBuq9qU

SAFETY Reminders

• Soldering and 3D printing operate at high temperatures so be cautious at all times
• This tutorial works with live exposed wires so use caution when handling them
• Make sure that you solder on surfaces that are heat resistant

First, start by using a can opener to remove the top of the can, and make sure to wash and dry the inside. Then proceed to sand the can and finish by applying a coat of spray paint of your choosing.

Measure the overall length of the can as well as the open that you created in step 1. For this can we see that we got an overall length of approximately 16 cm and an opening of a little over 5 cm. we will use these measurements to create a base in SOLIDWORKS that can be 3d printed.

Open a new part file in Solidworks. Start by creating a new sketch on the front plane to create a profile that will be revolved along an axis (the centerline) to give us the final shape. the profile looks somewhat like an upside-down L. create the shape and dimension it like the image above.

NOTE: the 5cm measurement from step 2 will be our overall width/radius. Once the profile is dimensioned, revolve along the centerline to create a cylindrical shape

The first hole that we will add to the base will be a square hole that will allow us to pass the power cable through. Create a new drawing on the top surface of the base and add a center line that bisects the circular face. Create a central square that is 1 cm wide by 2 cm long to allow the thickest part of the cable to pass through. Make sure that the entirety of the square is within the bounds of the base. Create an extruded cut through all of the base to finish the top hole.

Now create the backport that allows the cable to exit the base and allow for the projector to sit flush against a flat surface. Start back creating a new sketch on the front plane. Create a 1 cm by 1cm square and cut "through all" in the same direction as the top hole. Save as an STL file and 3D print it (color does not matter but a lighter color will allow for the base to light up.

Create a new SOLIDWORKS part. Start by creating a new sketch on the front plane and create a shape like the one above and dimension it in a similar fashion. The 13 cm length comes from the can being 16 cm long, by reducing this length we allow the can to partially slide onto the base for a cleaner look. Revolve along the longest line (orange line in the second image above) to create the final rod shape. Save as an STL file and 3D print.

Connect the two 3D-printed parts as shown above. Some light sanding might be required to make them fit together

Make sure that the surface you will be soldering on can withstand high temperatures. First, start by cutting the small end of the USB power cable and exposing the Vcc ("hot") and ground wires. make sure not to cut any of the small copper wires within. You can apply a small piece of masking tape to hold the LED strip if needed. Most LED light strips have a thin plastic layer to protect them so you may need to scrape that layer off from the copper terminal. Crape the plastic only off the "+" labeled terminal and the corresponding color that you want to use.

Very carefully if you are not 100% sure which cable is which you can plug your wire into a low-power source (such as a laptop and test the wires to see which setup gets the light to turn on. USE CAUTION AS THEY ARE LIVE WIRES.

Once you know where the two wires go you can now begin to solder! Apply a small amount of solder to each cable and the terminals on the LED light strip. This makes it a lot easier to connect the two. Once the terminal and the wire both have solder you can now melt them together. Make sure that you have a smooth solder with no jagged edges. Once they are both soldered you can test them once again to make sure e that everything works.

NOTE make sure that your solder iron isn't too cold or too hot. Solder typically has its appropriate melting temperature on its roll.

Wrap all exposed wires with care using electrical tape.

Using the adhesive backing on the lights wrap the lights onto the projector rod and insert the cable through the top hole of the base.

Using a drill make holes along the entire can to create what will be the stars. You can use a thumbtack as well but it can become dull and difficult after a few holes

TIP: get creative with your starts and add or create your own constellations

Using hot glue, attach the can to the base. You can add a drop of hot glue at the top of the rod to hold the can in place while you glue the bottom.

Enjoy the finished product!