Oreo Night Light

This is a short Instructable that describes building a small nightlight with 3D printed parts and some simple soldering of LED's to make it light up. I was teaching a short course to grade school students on introduction to 3D printing and electronic design and I needed a short project that we could do as a group in a couple sessions. The goal was to make something that they would care enough about to keep and also to learn basic soldering. I have never taught soldering to kids before and this was also my first exposure to how make subjects palatable to the grade school kids. I picked a project to print: https://makerworld.com/en/models/440968-secret-oreo#profileId-367197 from Sketchy. It is a series of perfect prints of an Oreo cookie that can be sized to fit your needs. I used the series that was slightly larger and able to hold a real Oreo cookie. I have provided a couple different ways to light them up. One very simple with some 5 Volt LED's on a strip and the other with 2 Edison filaments and some in-series resistors. Both work well and are easy to wire and solder--even for kids.

The materials are very cheap/easy to get on Amazon. You also need a 3D printer...I use a Bambu P1P...works great!

1. USB wire connector with male end $4
2. 5 v LED strip $0.83 per foot various colors
3. or Edison LED filaments $.05
4. 75 ohm resistors or near equivalent
5. soldering iron

The 3D printed parts are all printed in PLA--Matte without support. The internal holders of the LED's are printed in white. Depending of whether you used the Edison filament or the LED strip you only need one for each light that you do.The choice of color for the cookie is of course up to you but looks best in the original black and white.

The two edison electrodes are actually a small line of connected LED's. They need a resistor in series with each one to prevent the usual unlimited current draw and resulting burn-out. I used a 75 ohm resistor for each one but depending on your source of power and where you ordered your electrodes this may have to be modified. Be careful not to shoot too low or your resistor might overheat and melt. The electrodes have a positive and negative end...the positive is denoted by the small hole in the end of the electrode. The resistors fit into the recess at the bottom of the board and their wire ends poke up through the printed board to join with the positive wire from the usb cable. The resistors other end is soldered to each positive end of the edison electrode. (see photo) The negative usb end is soldered to one of the neg ends of the edison electrode and the other edison negative end is connected to the usb cable with a small wire tunneled over from underneath the board. All the wires are carefully soldered together as done in the photo. The kids did well with this actually as long as you guide their hands through the process.

This is definitely easier than the Edison electrodes although not quite as evenly lit. The LED strip is cut so that you have enough room for wrapping around the printed mount. About 6 in the variety that I got. The strips have designated areas where you can cut between LED's. The easiest way to solder these connections is to pre-solder the solder pads with a bit of solder before you connect the wires. Most of these strips come with adhesive to attach your strip to the outside of the printed holder. Trim the USB wires so that you have an adequate stretch of cable to attach the PLUS and MINUS wires to the corresponding spots on the led strips.

Just plug your cookie in to test your connections before assembling the cookie halves. Make sure you lead the USB wire through the hole in the "double stuff" layer before assembly and soldering or this will teach the kids a lesson on self-control and thinking through things before acting. The USB cable should be hot glued to the ring that holds it in position and the light disk can then be hot glued to the bottom cookie layer before assembling. This turned out to be a good beginning project to introduce kids to 3D printing and the concepts of circuit assembly and soldering.