Hardened Case for CGM Nightscout Users




Introduction: Hardened Case for CGM Nightscout Users

This project is for users of the Nightscout system. We are not waiting to put our CGMs in the cloud!

Nightscout is an open-source project to give Diabetic T1s access to their Dexcom CGM in the cloud. You can read more about Nightscout here or join the Facebook group here.

Step 1: You Need

  1. Dexcom CGM G4 Monitor
  2. Android Phone with Nightscout CMG Uploader Installed
  3. Cabela's Fly Box (Swing Leaf model, approximately $16)
  4. USB OTG Cable
  5. USB to USB Micro Cable
  6. Drill with large hole bit (I used a 1-1/4" Forstner) and small bit
  7. Exacto Knife
  8. Approximately 8" of Elastic
  9. Washi Tape if desired

Step 2: Prepare the Box

  1. Line up your CGM with where you would like it inside the box and mark the foam.
  2. Use your exacto, goo-gone, and elbow grease to remove the foam from the insert.
  3. Measure the lid and remove some of the foam in the same place on the lid. I didn't remove it all because I wanted some padding over the screen.

This is going to be a tight fit, and will keep the G4 from moving at all during daily abuse and use.

Step 3: Create a Pass Through for Cables

  1. Place the CGM on the divider, and mark two dots above the CGM and two dots below the CGM. This is where you will thread elastic, so consider your placement.
  2. Using a small bit (I used 3/32) drill four holes in the divider.
  3. Mark the middle of the right hand side of the divider.
  4. Remove the foam on both sides of the divider in the approximate area of your hole.
  5. Drill slowly! This divider is NOT thick, and not reinforced, so go slow. You might also consider using a block beneath it to provide support.

Step 4: Secure the CGM

  1. Measure the distance between two of your holes, and cut elastic to twice that, plus 1/2" extra to knot with.
  2. Use a needle, small toothpick, or small drillbit to thread elastic through the holes.
  3. Knot elastic using a square knot to create loops.
  4. Insert CGM on top of divider to make sure loops are tight, but not too tight.

Step 5: Run the Cables

  1. Thread the USB end of your connection cable through the large hole through the backside of the elastic loops, and attach to your USB OTG cable. Note that I did swap out the retractable USB cable in the first picture for this short 8" gray cable. It just fit better.
  2. Attach micro end of cable to CGM.
  3. Attach USB OTG cable to your phone.

You may need to add in a layer of bubble wrap in the lower level to keep your phone steady. Alternately, you could use a few velcro dots or some command adhesive to keep the phone in place.

Step 6: You're Done!

Close the lid, you're done. You may find the top a tight fit, but these devices are approved for human use. I believe this pressure will also hold the device in place better. You also might want to reinforce the CGM connection to the USB with washi tape to reduce the stress points.

Thanks for playing along. If you use this case, let me know, or post in the Facebook group.


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    3 Discussions


    5 years ago on Introduction

    This is great, James. Thanks. I love the do-it-yourself spirit of this group.


    5 years ago on Step 5

    Hi James,

    Thank you so much for this! I've been searching trying to figure out how to make / get / find all of the components to set up my Dexcom CGM to get my data to the cloud and to my phone, a watch, computer, whatever. Thank you for this additional piece of protection.

    Would you describe here, how having this protection for the CGM receiver helps with the data in the cloud setup? I have been seeing the CGM receivers sitting next to the phone/computer it's connected to -- how does having a secure case to hold it inside of, help?

    Thanks so much, James! :)


    Reply 5 years ago on Introduction

    It doesn't help with the operation, it just makes it more stable for putting in a backpack that goes to school, gets thrown around, dropped, etc. I built this case to put up with the abuse of an 11yo kid. I also find that the case is a tight fit, meaning the cables are moving less during the day, reducing any stress on USB ports in the system.

    Thanks for the comments! Good luck with your case!