Iron Man Arc Reactor with a Circuit Playground Express (CPX)

This if a follow up to my previous post about how to make an Iron Man Arc Reactor with a Gemma MO, except this one details how to make it with a Circuit Playground Express. This one can be programmed with MakeCode, making it  a great project for kids! They can easily program it do different patterns, colors, play music, and turn on or off if they clap their hands.

The 3D parts where remixed from an existing project by Aelkaim. I basically modified the Crystal Bottom to hold the CPX, and Crystal Ring to hold a 24 Bit LED ring.

Print all parts at 95% scale to work with the parts I link to below. I had to do this to fit the large LED ring. If you get different parts you may need to adjust the scale. I used alligator clips to reduce the soldering and make it more kid friendly. You could just use regular wires and solder it to the CPX.

Adafruit Circuit Playground Express
24 Bit LED WS2812 Ring

3 Alligator Clips
Spray Paint (Metallic Gold, Metallic Silver,"Hammered")
Copper Wire 24 Gauge (Ace Hardware)
3 X M3 16mm screws




Download the 3D printed parts on Thingiverse

Print out these parts in Transparent or Glow in the Dark PLA
01_Crystal_Ring
02_Crystal_CPX_Bottom
04_Crystal_Top

Print out these parts in ABS (I preferred this stronger material because the PLA kept breaking when I screwed the parts together)

05_Upper_Grid
06_Lower_Grid_Caps ( Printed with a Raft to keep the tabs from breaking off when I removed them from the printer. )

Spray paint the parts your desired colors.

Cut one end off of each the alligator clips and solder the three wires on the large LED ring (V++, GND, DIN) and place it into the Crystal Ring:

Place the caps on the ring, then wrap the copper wire around the caps. Don't wrap the copper wire too thick or the lower grid will not fit later if you do.

Use the three 3M X 16mm screws to screw the Upper Lid into the Lower Grid and Crystal Top. Keep the screws flush with the backside of the Crystal top:

Connect the alligator clips from the 24 bit LED ring to the CPX. Place them on the same output as show below as the Crystal Bottom has specific cutouts for it to fit.

LED Ground > CPX Ground
LED V++ > CPX Vout
LED Di -> CPX A1.

Place the CPX in the crystal bottom. Line up the USB on one side, and pull the alligator clips through the holes on the other side. If you are using a battery, plug it in and feed those wires through a hole.

Now place the crystal bottom and CPX with the Crystal Top, Upper Grid and Lower Grid you assembled earlier.  Use some hot glue to keep it together. NOTE: YOU MAY WANT TO PROGRAM THE CPX FIRST AS YOU WILL NOT HAVE ACCESS TO THE RESET BUTTON ONCE ITS GLUED TOGETHER. SEE THE BOTTOM OF THIS POST FOR THE MAKECODE.

Place this "core" inside the LED Crystal ring. Line up the clips and the grooves in the Lower Grid and it should settle into place. Use some more hot glue to secure the "core" and the LED ring:

The USB is accessible through the hole. I was able to program mine without using the reset button by plugging/unplugging the CPX each time I wanted to load the MakeCode.

Go to MakeCode to program the CPX. Below is the code I used for the effects shown above. MakeCode makes it easy to reprogram! Add in some musical tones, or have it turn off or on when you clap your hands.

Iron Man Arc Reator with Gemma MO and LED Rings

This project is a 3D printed Iron Man Arc Reactor. It uses an Adafruit Gemma MO to run two WS2812 LED rings. It can be powered from either USB, or a lithium battery. There is a case in the back that holds the battery and Gemma MO making it fully portable. There is a button on the back that will cycle though three different patterns and turn off the LEDs.

The 3D parts where remixed from an existing project by Aelkaim. I basically added in the case and lid that holds the Gemma MO and battery.

Print all parts at 95% scale to work with the parts I link to below. I had to do this to fit the large LED ring. If you get different parts you may need to adjust the scale.

Adafruit Gemma MO
24 Bit LED WS2812 Ring
16 Bit LED WS2812 Ring
Button
Spray Paint (Metallic Gold, Metallic Silver,"Hammered")
Copper Wire 24 Gauge (Ace Hardware)
3 X M3 20mm screws
2 X M3 8mm screws


If not running from a USB power source:

Tiny Lithium Battery
Lithium Battery charger (The Gemma MO will not charge the battery)

3D printed parts on Thingiverse

Print out these parts in Transparent or Glow in the Dark PLA
01_Crystal_Ring
02_Crystal_Bottom_MO_Holder
03_Crystal_Lid
04_Crystal_Top

Print out these parts in ABS (I preferred this stronger material because the PLA kept breaking when I screwed the parts together)

05_Upper_Grid
06_Lower_Grid_Caps ( Printed with a Raft to keep the tabs from breaking off when I removed them from the printer. )

Spray paint the parts your desired colors.

Solder three wires on the large LED ring (V++, GND, DIN) and place it into the Crystal Ring:

Place the caps on the ring, then wrap the copper wire around the caps. Don't wrap the copper wire too thick or the lower grid will not fit later if you do.

 Next, solder three wires on the smaller 16 LED ring:

Use the three 3M X 20mm screws to screw the Upper Lid into the Lower Grid and Crystal Top. Keep the screws flush with the backside of the Crystal top:

Flip the it over, and place the small LED ring in the Crystal Top:

Place the Crystal_Bottom_MO_Holder on top of the small LED ring.Make sure the wires from the LED are pulled through the hole. Line up the posts on the Crystal Bottom and finish screwing it it:

 Now its time to solder all the wires to the Gemma MO.

24 LED Ring
LED Ground  > Gemma Ground
LED V++ > Gemma Vout
LED Di  > Gemma D1*

16 LED Ring
LED Ground > Gemma Ground
LED V++ > Gemma Vout
LED Di > Gemma D0*

*make these solders on top so the screws can fit into the holes to mount the Gemma later.

Button
For the button, pull the wires through the top of the lid first before soldering the button. Once the button is soldered, pop it into the holes on the lid.
Prong1 > Gemma Ground
Prong2 > Gemma D2

Use two 3M X 8mm screws to mount the Gemma into the two posts in the case. Plug in and tuck the lipo battery in and close the lid.

To program the Gemma Mo, follow the instructions on Adafruit to get it set up with Arduino IDE and appropriate libraries. Follow steps 1,2 and 3 from this tutorial to do so.

Upload the following sketch from my github to program the two LED rings.