Light up the dark with this simple flashlight while illuminating the very basics of electric circuits. Also great introduction to measurement!

This is one of the projects for our Instructables: Made In Your Mind (IMIYM) exhibition at the Children’s Museum of Houston . Produced in partnership with Instructables, IMIYM is an exhibit where families work together to build different fun, toy-like projects that help construct knowledge and skills related to science, technology, engineering, and mathematics while instilling a “do-it-yourself” attitude in kids so they feel empowered to explore, tinker, and try to make things themselves. To learn more, check out the article here.

For this project, we were inspired by the Pocket Flashlight (LED) Instructable created by MattCP, but there are others on Instructables that are also similar. Often, the materials and process for building our projects are designed for use with a large number of visitors (we see over 800,000 annually) and the need to ensure safety in a mostly non-facilitated environment. So, yes, many of these projects have room for improvement in both materials and methodology, which is PRECISELY what we want to encourage the kids to do. So please do share your ideas for improvement and modifications!

Step 1: What You Need

1 - CR2032 3V Coin Battery - we get ours in bulk from Batteries and Butter
1 - LED, 5mm white, slow burning, 12,000-15,000 mcd - we get ours in bulk from Leading LEDs
1 - 6” x 4½” Self-adhesive foam sheet - available at most craft stores, but we get ours in bulk from Oriental Trading
Scissors
Pencil
Ruler

We are selective in our materials for cost, ease of use, and safety due to our high traffic (800,000 visitors annually). So, for our purposes, this design worked best. But you may have other ideas - please share!

Step 2: The Video

We offer optional video segments of each step for this project in the actual exhibit. Here is a compilation of all the steps.

Step 3: Cutting the Foam Squares

Use the ruler to measure and mark a point 1½ inches along the short edges from one of the long ends of the foam sheet. Draw a line across. Cut off the strip. Place the remainder of the foam off to the side to either take home as repair foam for when the battery needs changing or to return to the supply bins. Use the ruler to measure and mark points at 1½, 3, and 4½ inches along the long sides of the foam strip. Draw lines across. Cut along the lines to get four 1½ inch squares.

Step 4: Placing the Battery

Use the battery to trace a circle onto the center of two of the foam pieces. Fold each piece of foam in half and cut out the circles. Save the circles. Remove the backing from both pieces with and attach the two together. Insert the battery into the hole in the two pieces of foam.

Step 5: Adding the LED

Slide the LED over the foam and battery with the long wire on the “+” side of the battery and the short wire on the other side of the battery. Make sure to bend the leads back away from the battery so the LED is off before continuing.

Step 6: Building a Pressure Switch

Peel the backing off one of one of the circles from step 4 and place it over the battery and LED lead. Peel the backing off one of the remaining squares and attach it to the battery-LED foam. Only press it on around the edges, not the center over the battery or else you will bend the leads to permanently touch the battery. Repeat on the opposite side of the flashlight. Again, make sure to only press around the edges, not the center over the battery.

Step 7: To Use

To operate it, gently squeeze the center of the flash- light with your fingers and the light should turn on!

Your Pocket Flashlight is a “squeeze switch.” In order for any electrical circuit to work it needs three parts: a power source (battery), a path for electricity to flow (LED leads), and an output (LED). Circuits can either be open (“off”) or closed (“on”). The circuit inside the flashlight is open because the LED lead is not touching the battery. When you squeeze the foam and press the LED lead to the battery, it closes the circuit and switches the LED on.