DIY Dexcom Transmitter Reset App

DIY Dexcom Transmitter Reset App: Concerns, Questions, and Resources to Build It Yourself

This post is for all my fellow Dexcom users. This post goes over liability, what to expect, common questions, issues that may occur, and the resources my husband and I used to build the Dexcom Transmitter Reset App.

And let’s be real…it feels good to fully exhaust your transmitter as you have likely already been doing with your sensors. Oh, and then there are the bragging rights, but sadly only your diabetes friends who use Dexcom will fully appreciate this.

As a Diabetes Specialist who has T1D, I try and help, not just my patients, but all people with insulin-dependent diabetes. The more we can help, encourage, and support one another, the more we can lift the burden for all those with diabetes.

Dexcom Transmitter Reset App

First off, I have have had several people reach out to me asking about how to restart the Dexcom sensors with the newer transmitters. Although I have information on how to restart sensors with the newer transmitters, I have NOT done this myself. The reason is that I am have been resetting my transmitters and getting close to double the time with old transmitters. With an *old* transmitter meaning a transmitter with a serial number that starts with an 81- or an 80- I have been able to use the easier restart sensor method. When I do make the switch to a newer transmitter, you bet I will create an updated sensor restart post and video.

Transmitter Reset FAQ

Isn’t the transmitter dead after 3 months?

Nope. It is just in warranty for those 3 months. But that does not mean it is actually dead. By having good diabetes control there is less of a workload on your Transmitter, therefore it is not burning through it’s BLE (Bluetooth low energy) as quickly. Good control or not so great, the transmitter is warrantied for 3 months. If you reset your transmitter and you don’t have good control, you will likely still get extra run time, but not as much as you would if you had better control and less variation. With the goal variation (aka standard deviation or SD for short) being 1/3 of your average glucose number provided by a CGM.

Personally, after a reset, I get an additional 2.5-3 months, so I get about 5.5 – 6 months on each transmitter. I keep my average between 105 – 115 mg/dL (an A1c between 5.4 – 5.9%) with an SD between 15-26 mg/dL. I do not eat super low carb, but I do watch what I eat and I do exercise (but now profusely, a normal amount).

How will I know my transmitter is really dead?

This one is easy. Your Dexcom app will tell you that your battery is ending soon and when it does end, know that this round is actually dead. Really dead.

After your phone has let you know that you need to change your transmitter soon, you will get a message on your home Dexcom G6 screen that reads.”I have a new transmitter”.

What equipment do I need to build the Transmitter Reset App?

You will need…

  • Mac computer with Mojave or Catalina
  • Xcode (my husband had to update his to build the app)
  • iPhone
  • More details with the given websites below

If you loop, you will likely already have everything you need to build the Dexcom Transmitter Reset App.

What are the Benefits of Reseting my Transmitter?

Uh. Bragging rights. Duh. But on a serious note, as a group of people who are dependent on our supplies to stay healthy, I like to stay prepared and stock up. Especially during times of uncertainty. Also, life happens, sometimes we have a bad sensor or a bad transmitter, and if we have a spare, it doesn’t put us in a rough place until we can get our replacement(s).

Another benefit is that it can reduce our out-of-pocket expenses for those who don’t have the most amazing insurances, especially at the start of each new calendar year when you have a new deductible amount to fork over before your insurance will help.

Speaking of supplies…

You should SEE my supply cabinets. Yes. cabinets, meaning plural. It is well organized, but I’m talking 10+ Dexcom sensors and always 2+ transmitters on hand. Not to mention not only lots of sites, but I have sites for each of my 4 pumps: the classic Omnipod, the DASH Omnipod, the t:slim X2 tandem pump with Control IQ, and an old 530G Medtronic. All in working condition, although my Medtronic pump’s battery cap has seen better days. As a healthcare provider, I like to use different devices so I can share my personal experiences with patients and I like to have equipment on hand for local patients in case of emergencies. I also use first in first out (FIFO) with my supplies, so I can get the best use out of the equipment. Let’s just say, I’m ready to share the love and take care of my T1D friends if an apocalypse or shortage occurs. I like to stay prepared and stock up, as you probably do, which is why you are reading this post.


Before we dive in, I need to report, I am not the techiest of the bunch, but my husband is a programmer. If you are not great with tech, but you know somebody, you may very likely need that person to help you during this building process. This post is to give you the resources to build this, but moreso to go over concerns and what you should know before the reset.

Below is important information to know and to do to make building this Reset App a better experience.

1. Accept Liability

As an educator, I have to include the disclaimer of accepting liability when you use a “hack” to extend life or change the way the diabetes equipment was meant to be used. By hacking the device, the company (i.e. Dexcom in this case) is not liable if something goes wrong. And it could go wrong. Wrong is a very vague word, but what I mean is that you could have more faulty sensors, more issues with accuracy, more signal loss (oh, how we love signal loss…*sarcasm*), and so on.

Also, know that once you have reset your transmitter, Dexcom customer support can see that the transmitter has been reset, and although they cannot stop you from the reset, they will likely not give you a replacement sensor if you have a sensor that doesn’t work well for the full 10 days. You may get away with a rep not really paying attention if you try and replace a bad sensor on a reset transmitter, but you have been warned.

2. There may be Clarity Report Consequences

If you do build this Transmitter Reset App know that this app can reset the clock on a transmitter that has reached its expiration date. However, this reset may have unintended consequences with your Clarity Reports or the history section of other CGM integrated software (i.e. tconnect. nightscout, tidepool, etc), especially when using a reset transmitter with the same Dexcom login account.

Meaning, you may or may not have spotty data when you look back on your reports. This can be frustrating when working with a provider, but this doesn’t happen to everyone. Spotty Clarity reports happens to me when I used this reset app the first time, but when my husband built it for my friend’s iPhone, she did not have noticeable issues with her clarity reports.

This is the message I received on my phone when I went to my 30 Day clarity reports.

Possible Network Error after Transmitter Built

I had a bad sensor that said I was LOW for many hours during the early morning. Needless to say, it was a rough night, but I checked and it was 90 mg/dL, so don’t pay attention to the 2% urgent lows.

*UPDATE* I have been using my reset transmitter for 4 days now and I do not appear to have any missing data on my through my Clarity Reports.

3. RESET at the END of your Transmitter “Life”

I should have screenshotted this, but when you start getting the message that your transmitter is ending soon, ignore and press onward. To get the MOST out of your transmitter, wait until you have to change your sensor until it is super duper dead, and when you go to change the sensor, the Dexcom app reads. “I Have a New Transmitter”. That’s when you know your transmitter is D.E.A.D. Well…that is until you revive it again…

Once you see this screen (so you are not in a session), you will want to use your Transmitter Reset App.

To add to this, you will end your current sensor session. So make sure you use the reset app when you have to change your sensor for a new one OR when you are restarting your current sensor.

4. Several Tries May Be Necessary

What I mean by this is that you will likely need to do some research while building your app. Make sure you are using updated Xcode, that you are coordinating with the right iOS with your computer and your phone, and if it doesn’t build right, don’t’ give up, troubleshoot, research, and try again.

When you finally get it to build onto your phone, know that you may also need to reset more than once for the reset to work. The first time I did this, the reset took 3 times, while it only took one time for the second transmitter reset.

5. Transmitter Reset Websites

Github is where the code has been developed and shared, below is the website to find the detailed instructions:

Second, seemycgm is a fantastic website created by @diabetic.anna. This post was written a couple years ago, but it is still a great resource to get started. Anna has many other helpful posts and I have been very grateful for her work and dedication to the diabetes tech community. Below is the post that will be especially helpful for you during your Transmitter Reset Building session.

Hopefully, this has been helpful for you. I hope you are doing well and I wish you the best with your diabetes management, your health, and happiness.

As always, if you are struggling with your diabetes (newly diagnosed or a long-time veteran). Perhaps you need are at the end of your pump warranty, or have always used pens and are considering a pump. Maybe you need setting adjustments or want to learn how to make your own adjustments safely. Maybe you want insight on how your nutrition is affecting your insulin sensitivity and your control, or you want to work with an HCP who understands on a personal level what it feels like to have diabetes. Do not hesitate to write me an email or schedule with me for a consultation. I’m here to help you. I love helping people like you increase their control, understand your diabetes, and get your life back so you can be with the people you love and live the life you want.


Ariel Warren, RDN, CD, CDCES

UT-ADCES 2020 Coordinating Chair-Elect

Diabetes Care & Education Specialist

Type 1 Diabetes for the Newly Diagnosed

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