Introduction: LED Swirling Soft Serve

What do compact fluorescent light bulbs (CFLs) and soft serve have in common? Their iconic swirls!

This project combines these iconic swirls together to create a light-up, color-changing ice cream cone. You'll need some RGBW LED strip lights, a microcontroller, a button, a 'cone,' and a CFL-style bulb.

[WARNING] Do NOT get a CFL bulb and crack it open!
CFL bulbs contain mercury, which is poisonous. Instead, you'll need to find an empty bulb shaped like a CFL. I used a CFL bulb that had LED strips in it which you can purchase on Amazon (link below). Alternatively, you may try to use plastic tubing swirled in an ice cream shape, or 3D printing the shape using transculent ABS.

The other unique supply you'll have to source is the cone. I used an old oil can spout which already had an ice cream cone shape and a hole in the bottom. You may also make a cone with clay or other materials, just make sure there is a hole at the bottom for the wires to run out of. Another idea is to get a real ice cream cone and varnish it (see tutorial here).

Supplies

For the Ice Cream

  • Swirling glass or plastic tube/bulb *do NOT use a traditional CFL bulb
  • Cone
  • Frosted Glass spray paint (if glass bulb is clear)

For the Wood Box

  • Wood
  • Saw
  • Drill and screws
  • Hole saw drill bit big enough to create a hole to hold your Ice Cream
  • Wood stain or paint
  • Sanding materials
  • Sheet metal (optional)
  • Wood filler

For the Electronics

For the Sign and Button

  • Sheet metal (cut one rectangle to fit your wooden top front cover, and one circle to fit your button cover)
  • Button cover, or plastic Ice Breakers candy container to make one
  • Clear lacquer spray
  • Wood glue
  • Sanding materials
  • White paint
  • Printer

Step 1: The Ice Cream

  1. If you need to make your cone, do so now.
  2. Detach the glass/plastic tubes from the rest of the luminaire.
    If you're using the spiral LED bulb from Amazon, first detach the bottom from the bulb and bulb holder. Cut the black and red wires with wire cutters to fully detach. You may use the bulb like this, with the white bulb holder still attached. Alternatively, you may very carefully cut the glass tubing off of the bulb holder with a glasscutter or file.

Step 2: The Wood Box

  1. Using your Ice Cream as a guide, cut 9 pieces of wood to create a box with a top compartment, bottom compartment, and middle shelf to hold the ice cream cone.
    You'll need a left side and right side (same size), four shelves (same size), a back cover, and two front covers. My box's dimensions were as follows: side pieces 20" x 7", shelves 7" x 9.5", front top cover 12" x 6", front bottom cover 12" x 7", back cover 18.5" x 12". My frame and shelf pieces were 1" thick, and my covers were 1/4" thick. You'll want to measure the wood that you have and adjust the cuts accordingly. Before you continue, put the pieces together to make sure they fit together to create the box.
  2. Using a hole saw, cut a hole in your bottom middle shelf.
    The hole should be big enough that the cone can be inserted to stand up securely, but the bigger the hole, the more your cone will be covered. The size of the hole will be greatly dependent on what kind of cone you used.
  3. Assemble the box frame and shelves.
    Clamp the frame (two side pieces, top and bottom shelves) together, and using a drill and screws, join the pieces. Drill the screws in past the surface of the pieces, as you'll use wood filler later to create a flat surface. Next, clamp and join the shelves. Stand the box upright and check how it looks with the cone inserted.
  4. Drill a hole in the middle of the front bottom cover, then attach the front and back covers.
    Make sure that the covers fit correctly. Unscrew/detach the covers before moving onto the next step. The hole in the front bottom cover should be big enough to run two wires through, but small enough that your push button will not fall through it.
  5. Use wood filler to fill in the indents from the screws.
  6. Sand everything.
    Give the box and covers a good sanding to prep for wood stain or paint.
  7. Stain the wood or paint to your liking.
    I used a semi-transparent wood stain in the color Red Mahogany. Let the wood pieces dry as the stain or paint package directs.
  8. Reattach the back cover, optionally with reflective material on the inside.
    I sandwiched some sheet metal between the frame and the back cover when screwing the back cover in to add some reflectivity to the inside box where the LEDs will be. This is optional.
  9. Leave the front two covers unattached.
    You will use them and reattach them later.

Step 3: The Electronics

  1. If you are using a CFL style bulb, you may want to cut the 1m LED strip in half.
    Two half-meter strips may be easier to get into the bulb (one through each bottom tube opening). The schematic shows how to connect the two halved strips as twins using the same data line. The provided code is written for two halved strips; if you use one whole strip, you'll need to change line 5 to "#define NUMPIXELS [number of neopixels you used]". If you are using the full meter strip, that number would be 60.
  2. Insert the LED strip(s) into the bulb.
    Blowing pressurized air into the tube while you are inserting the strips may make this easier. You will need to solder longer wires/headers onto the LED strips' provided wires, long enough to runt though the cone into the bottom compartment of the wood box.
  3. Test the LED strips, then attach the bulb with the strips inside to the cone, running the wires through the bottom of the cone.
    You may use hot glue to attach the bulb to the cone.
  4. Connect the electronics using the provided schematic.
    You will need to solder wires onto the push button long enough to reach from the back of the front bottom cover to the inner bottom shelf of the wood box. If you are not using a breadboard, wait to permanently connect the button's two wires, as you'll need to run them through the front of the box
  5. Upload the provided code to the Arduino microcontroller using your computer.
    The code is in this Github repo, file icecreamLEDs.ino
  6. Press the button to cycle through 9 color modes (strawberry, vanilla, chocolate, strawberry-vanilla swirl, chocolate strawberry, vanilla-chocolate swirl, and Neopolitan).
    In the function changeLEDMode(), you can change the colors to any GRB value you'd like (note that the Green and Red are switched in the color code).
  7. Disconnect the microcontroller from your computer and put all of the electronics materials (except the button) into the bottom shelf of the wood box.
  8. Place the button in the middle of the front bottom cover, and run its two wires through the middle hole you drilled earlier. Connect button wires back to the system.
  9. Insert the cone into the bottom shelf, running the LED strip wires into the bottom compartment, and reattaching to the system there.
  10. Connect the microcontroller to power using the switching power supply.
  11. Reattach the front bottom cover to the wood frame.

Step 4: The Sign and Button Cover

  1. Make the button cover.
    I used an empty Ice Breakers candy container bottom. You're going to glue the inside of it to the top of your push button so that it clicks the push button when you press down on the top. You can use any plastic button shape top that will achieve this; you may need to cut it down to fit. Remove any labels or stickers on the plastic cover by soaking in soapy water or using Goo Be Gone. You may want to sand and paint the button cover to match the rest of the project (I painted mine white and then coated it in clear lacquer).
  2. Make the top sign and the button cover sign.
    I used the following Instructables to make the signs with sheet metal and printed designs: Making Reproduction Vintage Tin and Timber Signs
  3. Glue or drill the metal sign to the top of your box, and clue the button cover sign to the button cover.
  4. Hot glue the button cover onto your push button; test that it works.
    I recommend using hot glue as it will be easier to force the button and button cover apart if you need to redo something or cut down the button cover to make the button functionality work.
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