A step-by-step guide on how to make coasters light up when you set your drinks down.
What is it?
The Illuminating LED Coaster is a simple and inexpensive way to build your own transparent LED powered coaster. This step-by-step tutorial is designed to help one create his or her own Illuminating LED Coaster using easily available and affordable materials.
How does it work?
The Illuminating Coaster will simply remain off until a beverage is placed upon the coaster. In essence, the coaster acts like a “pressure sensor.” The weight of the beverage causes pressure to the positive lead of the LED, which in turn, makes contact with the positive side of the 3V lithium battery, illuminating the LEDs inside the coaster.
Step 1: Materials and Tools
In order to successfully create your own coaster, the following items are needed. Each set of materials will be used to build one coaster.
· Two Acrylic plastic sheets (0.05 inch thickness)
· Four 3mm LEDs (any color)
· Two 3V lithium batteries
· Foam insulation tape
· *Plastic cutter (acrylic cutter)
· *Hot glue gun
· *Soldering iron
· Straight edge
*Please note to always remember to use appropriate safety equipment including eye protection and gloves when using the plastic cutter, hot glue gun, and soldering iron.
Step 2: Prepare the Acrylic
Using a ruler, measure and trace a 3.5 x 3.5 inch square on each plastic sheet of acrylic (0.05 inch thickness). Next, using a straight edge, place the point of the plastic cutter’s blade at the edge of the acrylic. Firmly apply pressure and draw the point across the full width of the sheet. Slice through the acrylic until the acrylic seems ready to snap off or separates completely. Repeat entire process again for the second square. ***Also note that a jigsaw is an acceptable alternative to use to cut through the acrylic as well.
Tip: This step can be a little exhausting and frustrating, do not try to snap off your piece too early or you will crack your entire sheet in half!
Once both acrylic squares are made, use the scissors to cut off the appropriate amount of foam insulation tape to form a square perimeter along the edges of one of the acrylic squares. Peel off the back of the foam insulation tape and apply to the acrylic square as shown in Figure 3.
Step 3: Attach LEDs to Battery
Select one of the 3V lithium batteries and place it on a table with the negative side facing up. Next, position the negative leads (the shorter lead) of two LEDs to cross over on another near the center of the battery in a “V” like position as seen in Figure 4. Using a soldering iron, solder the point at where the two negative leads intersect. Remember to apply enough solder so that the two negative leads are also soldered to the battery. Repeat this process for the other battery.
Tip: If you are unfamiliar with soldering, please watch this video for a quick lesson.
Now that the negative leads are soldered together and to the negative side of the battery, flip the battery upside down to the positive side. With a little repositioning, align the two positive leads of the two LEDs so that they form a small intersection point near the tips. Apply solder to this intersection point, but DO NOT solder the positive leads to the battery, otherwise the LEDs will constantly remain lit. Repeat this process for the other battery.
Step 4: Attach Circuitry to Acrylic
Position the two batteries with their respective LEDs attached onto the acrylic piece with the foam insulation tape with the negative side of the batteries facing down as shown in Figure 5. Next, using a hot glue gun, apply glue to the bottom side of the batteries (the negative side) as needed and adjust the battery placement so that the batteries are level with rest of the acrylic piece and the LEDs face all four corners of the square.
Tip: Since using a hot glue gun can be a little tricky and messy, this step will require some patience. Also remember to check the height of each battery so that they are level with the foam insulator.
Step 5: Assemble Housing
Before completing the final step of this tutorial, test the functionality of the LEDs by simply placing the other 3.5 x 3.5 inch acrylic square on top of the coaster and applying pressure to the center. All four LEDs should light up, but if they do not, adjust the height and angle of the positive leads of the LEDs. Once all four LEDs properly light up, apply hot glue along the perimeter of the foam insulation using a hot glue gun and then place the other acrylic square on top, sealing the coaster.
Tip: Remember to test your coaster by placing a beverage on top before sealing it to ensure complete functionally.
Step 6: Enjoy!
Your Illuminating LED Coaster is now ready to impress your friends! Enjoy!