Dexcom Speeder

Introduction: Dexcom Speeder

If you use a Dexcom G6, you know how cool the applicator looks. Don’t throw that’s cool design away, mod it into a cool Speeder for your kids’ LEGO minifigs

(If you don’t know what a Dexcom G6 is, count yourself lucky as it means you don’t have diabetes. )

Read all the instructions thoroughly, figure out what you want to do and what you need, then start from Step 1.

Coming soon... A glue-only option. (i.e. No drilling required.)


  • Dremmel rotary tool
    • You will have to experiment with bits. See photo in a later step of the ones that I have used the most.
  • 3D printer
  • 3D models from

  • X-Acto knife
  • Flat File
  • Plastic glue. One or more of the following
    • Acetone (nail polish remover) - needs perfectly touching parts. Creates a "weld" rather than a glue bond.
    • Model Airplane glue - available in your local hobby shop.
    • Epoxy putty from the plumbing section of your hardware store. Good for the inside of the speeder.
    • Sugru molding putty. Similar application as the epoxy putty. Also available in non-toxic version if you have toddlers who chew on everything.
    • Epoxy glue. Works well, but is quite shiny if you get any mess.
    • Superglue (aka CA) - I have not tried it. Probably works well for close-fitting parts.
  • Optional
    • Lego 4081 pieces (see photo). If you don't have some, they're cheap from
    • Hacksaw
    • Jig for cutting/drilling - made out of LEGO
    • Drill Press
    • LEGO for gluing to speeder
    • Model airplane decals (or other stickers)

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Step 1: 3D Print Your Parts

Get the stl files from and select the ones you want.

For any rectangular cockpit you will want the cutting/drawing jig.

3D print them. No special instructions necessary for printing.

The rectangular cockpit looks good in many colours, but if your hole isn't an exact fit, the white hides your mistakes better.

Once you have your parts, you may need to cut away some supports as indicated in the photo. Your 3D printer may put some difficult-to-remove supports on the round cockpit; just work at it for a while and it will all come loose.

The front blaster piece doesn't print that well and you will likely need to sand it to make it mate perfectly with the orange button. You can do this by taking an orange button you have removed when making a circular cockpit and using it as a sandpaper holder to sand the front blaster piece. Works quite well.

Step 2: Optional: Make a Jig Out of LEGO

To hold the scooter steady while you drill or otherwise manipulate it, you may want to create a jig.

Make a jig with interior dimensions 6 bricks wide (exactly) x 8 bricks long (minimum) x 4 1/3 bricks high. In the front, after second first layer of bricks, make an overhang one brick deep.

See photos

I thought this would be super-useful, but I didn't actually use it much.

Step 3: The No-Cut Cockpit Option

If opening up your Dexcom and dremeling out the insides is a bit much to take on at first, this option is for you.

  1. 3D print your cockpit and base filler.
  2. Carefully remove any supports required for printing, and sand it smooth on the bottom.
  3. (Optionally open up the dexcom and remove the needle assembly. See next step.)
  4. Figure out where the cockpit fits best on the Dexcom, and glue it on.
  5. Glue the bottom filler plate on.
  6. You're done. Go to the "Add Further Flourish" section for finishing ideas.
This design is new. Photos to come.

Step 4: Open Up Your Dexcom Applicator

  • Take your X-Acto knife and cut off the heads of the plastic rivets on the back.
    • Place it vertically beside the rivets and then twist and pry and cut.
  • Pry open the Dexcom from the front with a flat-head screwdriver from the front or back.
  • Carefully remove the needle injector and dispose of it in your sharps container.

Step 5: Choice A: Rectangular Cockpit

    The Rectangular Cockpit

    1. Apply Masking tape to the top of the Dexcom. Align the seam between pieces along the centre line of the Dexcom.
      1. Leave the tape on as long as you possibly can as it will protect the surface against melting plastic and accidental marring.
    2. Use the 3D printed cutting guide to draw your rectangle.
      • The guide is conservative: it is the precise size of the hole, with no allowance for pencil offset. You will likely need to do more cutting/filing after using it. I should probably make it bigger.
      • The cutting guide is only made for a 4x2 cockpit even though .STL files for 3x2 and 2x2 are also supplied.
    3. Cut out much of the rectangular hole with a cutting disk. Use a smaller disk or metal disk for the rest. At this point, the plastic will not fall out.
    4. Turn the top piece over and cut out all the insides. Go crazy, leaving only the side pieces (see photos) but otherwise clearing everything out.
    5. The width of the cockpit will align with the interior support members inside the Dexcom. These can become your guide once you've made your initial cuts.

    6. You can pull out the round spring cover and spring with a pair of pliers.
    7. Eventually, the rectangular hole will pop out.
    8. The dremmel is extremely imprecise. You can clean up afterwards with an x-acto knife and file.

    9. Use a file from the inside to align the sides of the hole with the inside walls.
    10. Try sliding the cockpit in, see where it doesn't fit and use your file or x-acto knife to cut out more plastic.
      1. Use the cutting guide again to draw lines for further x-acto cuts. This is better than eyeballing it.

    11. To fit the cockpit in vertically, you will need to cut very close to the inside guts of the front orange button.
    12. Keep sliding the cockpit in, and if it doesn't quite fit, carefully trimming small amounts of material.
    13. You may also need to slightly cut some material on the cockpit itself to get it to fit. Well, not the cockpit itself, but there may be remaining support bits that you missed shaving off in the "3D print your parts" section. If the cockpit isn't quite fitting, have a look back at that page.

    Once it all fits, fix your cockpit from the inside using epoxy putty. (Or use your chosen glue however works best.)


    • You can add 1/3 height lego pieces inside the cockpit to make your minifig sit higher.
    • The 3D printed LEGO studs on the exterior are probably not going to hold things as well as real LEGO. If you find them not doing the job, holding on some massive antenna, you could just glue a two small circular 1x1 studs (or a 2x1 rectangular piece) to the cockpit studs and now everything will be LEGO-to-LEGO joints.

    Step 6: Optional: Front Blaster

    3D print your part. Glue it on.

    The front blaster piece doesn't print that well and you will likely need to sand it to make it mate perfectly with the orange button. You can do this by taking an orange button you have removed when making a circular cockpit and using it as a sandpaper holder to sand the front blaster piece. Works quite well.

    The 3D printed LEGO stud on the exterior is probably not going to hold things as well as real LEGO. If you find it not doing the job, holding on some massive antenna, you could just glue a small circular 1x1 stud to the blaster stud and now everything will be LEGO-to-LEGO joints.

    Step 7: Choice B: Circular Cockpit

    The circular cockpit may have a lot of support pieces that you will need to cut out. See the above photos.

    From the inside, Dremel out the parts holding the orange button.

    • Cut out the plastic supports and pop out the button.
    • Go crazy cutting out everything vertically under and in front of the circular hole in the white top.Even the female pins.
    • Dremel out the bottom gray plate as shown in the images.

    Insert the round cockpit from the top. You may need to insert it sideways. If it doesn't quite fit, trim it a little with an x-acto or sandpaper.. It should fit nicely into the bottom of the scooter. If it does not, you may need to trim more material out of the Dexcom.

    Try putting your LEGO minifig in the seat. It should fit both standing and sitting.

    Insert the bottom filler plate and mate it with the cockpit. You may need to file it slightly to get a perfect fit. Once you have a good fit, glue them together.

    (I need to work on the mating of the bottom filler plate and the circular cockpit. I think the hole in the filler plate should be farther back.)

    Step 8: General Dremeling Notes

    This is, in many ways, the most complicated step.

    • You will need to take out a lot of material. Go crazy.
    • Rotary tools seem to have a mind of their own and will zip off and accidentally mar your work. Keep this in mind and go in a direction so that it is less likely to zip off and if it does, it will only mar the inside, or something unimportant, not some exterior bit.
    • The instructions are going to be rather vague, you just have to do it and see as you go what needs to be done.
    • You will have to experiment with which bits work best for you. I have included photos of the ones that work best for me. I started using about 12,000 rpm as going faster, the plastic melted a lot. Then I tried 30,000 and while it was very melty, it cut a bit better.
    • Be careful of your tools getting coated in molten plastic. If they do turn it up to 30,000 and cut some wood to clean.
    • Depending on which cockpit you are going to install, you will need to dremmel out different sections of the dexcom.
    • For the round cockpit, you will need to remove everything under the orange cap in the white top part, and in the grey bottom, you will need to remove everything in the front section. See photos.
    • For the rectangular cockpit, see the photos for guides.Remember, that you need to clear a space vertically below your hole. As the top of the dexcom is at a 30 degree angle, this is not perpendicular to the surface, as you hold it upside down to dremmel.

    Obligatory Safety Notices.

    • Be CAREFUL. Rotary tools have a mind of their own. Keep your fingers out of the way because the tool will zip out of your control occasionally.
    • Do not let your kids use the dremmel.
    • Follow manufacturer's safety procedures and use eye protection.

    Step 9: Optional: Add Holes for Side-weapons/thrusters

    Using a drill press and your LEGO cutting jig, cut 8mm (5/16") holes in the sides of the dexcom.

    Insert pieces as shown. Glue with Sugru or epoxy putty.

    LEGO part number is 4081. (They are quite cheap to order delivered from

    (I have ideas about 3D printing custom attachments for this step. But that's a future version of this project.)

    Step 10: Glue the Top and Bottom Back Together

    Mate top and bottom. Make sure they fit nicely.

    Apply glue to male and female guides and all along the seams. I used model glue and a paintbrush and that worked quite well.

    You're done!

    Step 11: Add Further Flourish

    Add model airplane decals that you can get from your local hobby store.

    You can optionally add LEGO in a number of places. Experiment. (If you find that your LEGO no longer attaches to the 3D printed studs, you can always permanently glue a single real piece of LEGO on and then all subsequent pieces will work normally.)

    You can glue studs to the back. (Photo above)

    Rather than adding side holes for lego 4081 as suggested earlier, try adding two Lego Technic pins, spaced 3 lego units apart so that you can snap on a LEGO Technic 1x brick with side-holes and attach a wing to that. (Having a 3 unit separation rather than 3 unit allows you to potentially have some pivot it you just want to use one of the pins.) See photo in the "thrusters" page.

    Step 12: Give Me Feedback

    After you've built your speeders, let me know how it goes, let me know if you have suggestions. I'm especially interested in ideas that add "play value". (I'm very concerned that this is super-cool from parents' point of view but kids will say "meh".)

    Ideas for feedback information:

    • Ideas for better cutting/dremeling tools/techniques
    • Ideas for modifications to existing 3D parts that add more play value. Ideas from your kids, not from you. :0)
    • Ideas for new 3D parts. e.g. Thruster/blaster LEGO attachment points that can be added anywhere on the side or back.
    • Better glue information.
    • Things that you've tried. e.g. A hinge-opening rear compartment.

    email me: dexcom.speeders (at) gmail (etc)

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      2 Discussions


      25 days ago

      Such a fun project! Really clever reuse :)