DIY LED Pendant

I made a small LED pendant with 8 neopixel LEDs. The pendant can be put in a chain or a bracelet, it also has a cavity at the back to put in a magnet. It has a micro USB port for changing the flashing patterns and looks like a regular pendant until the magic happens!! I programmed the LED's to flash a heartbeat-like pattern where the flashing LED jumps up the array with a longer gap between every two jumps.

For this project, I've used the following supplies:

1. Adafruit trinket M0
2. Adafruit Neopixel 8 RGB LED stick
3. 3.7V lipo battery
4. Soldering iron
5. Solder wire
6. Wires
7. 3D printer (with white filament for best results)
8. Super glue (optional)

The circuit for this project is very simple.

First, solder the wires to the data in side of the Neopixel stick ( It's important to solder on the data IN side). In order to keep the pendant compact, I did not solder the header pins on the trinket and soldered the wires directly on the board. Connect the ground of the Neopixel stick to the ground pin on the trinket, connect the 4-7V on the Neopixel stick to 3V on trinket M0, connect DIN to pin 2 on trinket.

For the battery connections, connect the ground of the battery to ground on trinket M0, connect the positive wire to BAT on trinket and THAT's IT!! YAYY

Upload the attached code to the trinket and you're ready to go! (refer to this page if you are using trinket for the first time)

The two part enclosure has been designed with features to snugly fit all electronics.

Just trim the wires short enough so that they fit in the enclosure and press the electronics against the walls to mount them. The two parts snap lock to each other but you also use a drop of super glue to make sure the pendant is closed properly.

I 3D printed these files on my creality CR 10 with 0.16mm layer height and 35% infill. (since the parts are small, it is recommended to use finest quality settings for the print)

Enjoy wearing the pendant to a party or a concert! Play with the patterns and colors :)

The next steps for me on this project are to swap the trinket m0 with a board that also has a charging circuit for the battery or just attach a JSTconnector to the trinket for easy removal of the battery.