Open Source Medical Devices - I want to change things

Hello Everyone,

I know that I am new here but I'm going to get right down to it. Let me tell you a story, and then tell you what I plan on doing. I'm a 26 year old type 1 who was diagnosed about 5 years ago. I managed to recognize the symptoms before anything bad happened(Drinking lots, frequent urination, blah blah we know the story) and took myself to the doctors. I should mention that I have never been a fan of the medical system, and how they have adverse effects on progress, but well get to that later. My doctor pretty much confirmed my worries and took a blood sample. A couple days later she brings me in and tells me that I'm diabetic, blood sugar was at 18mmol/l. It was a Friday evening so I guess she wanted to get out of there and basically sent me home with no knowledge of what to do next. Didn't give me a lecture on what to eat, anything I should take, just sent me home. This still amazes me to this day. Thankfully I(and my Mom as well) do a lot of our own research, and managed to not put myself in the hospital over the weekend. After finally figuring everything out - insulin, testing, etc. - I decided the best for me was to go on a low carb diet. Now I will just make this clear right now. I don't force my views on anyone. Low carbing works for me, and may not work for you, all humans are completely different, so whether or not you agree with low carbing, that is what I do to help with my blood sugar. I've been on this diet since day 1 and I consider myself healthy and fit. I'm also pretty active.

Since that time I've put myself through undergrad and now doing my Masters studies. I would say that also in that time I became somewhat of a "Maker" or "Inventor" but basically I play with and develop cool electronics and I am trying to make a business and a career out of it. An example is my Energy Harvesting Ring, which was featured in Popular Science Magazine; you can see it here: or here :
My company is called Idle Hands Development, and one of my first projects is a Balancing robot aimed at teaching kids/adults about robotics. I also love Open source, and my beliefs are that information and knowledge should be free. This is my website if you want to see it.

By entering this realm of creation and making, I discovered that I don't need to wait for big billion dollar medical industries to make things happen or change. I'm not going to get into the whole debate on how it's in their best interest to keep selling more drugs and endless test supplies, some of you may agree, some may not. Basically I want to better my own personal life, and as a result yours as well. I want to develop open source testing hardware that as a result of being open source, will be extremely inexpensive and/or possibly free and be developed by us. I have read numerous papers on non invasive glucose measuring techniques, and I am currently in development of a couple of designs. One that uses light levels and another that uses capacitance. Here is the light model that I have designed so far. It clips onto your ear and measures different wavelengths of light through the skin.

Both of these designs have no disposable aspects to them. I know I sound very optimistic, but I truly believe that a development of this sort can and will exist. It needs to be pulled away from the business of creating supplies and instead be put towards actually bettering human lives. One thing that gives me a great leg up on others is that I'm a diabetic who just wants to design something that works, and works well. I'm not an academic institution trying to get funding, or a company trying to sell you something. I want this device for myself.

I do have another project on the go, and it bears me asking you from the forums for some help. Currently I've been trying to get a Dexcom CGM for myself. I can't personally afford to pay for one right now, so I'm looking into my insurance to see if they will cover it. It will probably be a fight. Anyway, after looking into the Dexcom system, there is something that completely boggles my mind. This comes from my experience with electronics and my ability to know how those electronics work and how much they cost. The transmitter unit. I cannot believe for a second that they are charging $600 for this unit. I'm not talking about the sensor or the receiver with the screen, those are expensive but possibly cost a bit to make. Its the transmitter that only last 6 months that just is thrown away and must be bought for another $600. I can guarantee that this is a $5 piece of electronics with a $1 battery. The fact that they do not make the battery accessible is the biggest money grab I have ever seen. So the project I'm working on is like this; I want to design a housing for the sender and battery which makes the battery replaceable. So what I need from one(or a couple) of you forum members is to send me one of your *dead* Dexcom batteries that I can take apart. One you would just throw away anyway. If you have one please get a hold of me on here, I will pay for shipping or whatever you need. The plan is to make a housing that allows the changing of the battery and be able to save people possibly $1000 a year to those who use a CGM.

I know that was long and I didn't say everything that I wanted to. I don't normally type this much but I wanted to give the whole picture so everyone knows what I'm doing. Please ask me plenty of questions, and be open to new ideas. This stuff isn't for everyone and it will be a challenge but I believe if any change is going to be made, it will be from individuals who want to see the change, and not just make the money.

Sean H.

-I'm Type 1 Diabetic Inventor/Maker, been in magazines and have done talks.
-I'm working on open source medical devices to better peoples lives and my own.
-I need a Dead Dexcom Transmitter if you have one.
-Ask me Questions.

1 Like

Sean - I like your style. I followed your links and you seem to be a fine example of an amateur. I mean this in the best sense of the word, one who pursues an activity purely for the love of it!

I'm avidly following the "we are not waiting" grass-roots movement of people like you who have taken it upon themselves to help themselves. No need to wait for Big Med-Device Manufacturer to finish their dance with their investors and the FDA and instead forge ahead in a people-powered movement.

There's evidence already that Dexcom, as well as the FDA, has responded to this movement. Dexcom unexpectedly released a software upgrade to existing customers after incorporating what it learned the artificial pancreas trials. Just last week the FDA has softened the regulatory path going forward for remote monitoring devices, like smartphones, to receive and forward blood glucose data. This "Dexcom Direct" system should be available in March, development that happened at light speed in regulatory terms.

But let's cut to the chase. I have an old Dexcom "sensor transmitter" for you to use. I'm glad I didn't throw it out as it has no value to me. Just send me a TuD friend request and we can private message the details for getting this in your hands.

I suggest that you edit your post to use the words "sensor transmitter" or simply "transmitter" instead "battery sender" unit. Many people mix up the nomenclature of the components in Dex's CGM system.

Good luck with your project!

I was looking into the Dex system myself last week, and thought about cracking open a transmitter to see what the battery requirements were. I'd be interested in helping out if I can. I'm an electronics geek myself. I do a lot of work in computers, I'm a licensed amateur radio operator, do some software programming, and tinker with electronic devices and some light circuit stuff. If I can help in any way, let me know.

Not sure which discussions, but you can find them with a search, or someone else here will post links.

Anyway, save yourself some time -- replacing the battery in the G4 transmitter is a project that has been done, and reinvented, by at least half a dozen people. Take a look at their work to get a head start.

Also, some feedback: The G4 transmitter is already a bit "bulgy" for some people, so any addition to it that increases its size much probably won't find too many interested. However, engineering a clever way to modify the original housing to replace the battery inside, without changing the form-factor significantly, would be huge! Problem is, you have to practically destroy the thing to get at the battery.

This "Dexcom Direct" system should be available in March

First I heard of this... fantastic news! Any links, Terry?

Here's Mike Hoskins DiabetesMine column from January 28, 2015.

Here's a link. I should have mentioned this, too.

Perhaps you can reverse engineer and build one from scratch, rather than excising and replacing the existing battery. Dexcom would hate that and it would likely void all warranties, but if it works, you can't argue with success. On second thought, this is probably a minefield of patent infringement. What if the plans just showed people how to do it for themselves? The joys of a 21st century inventor!

Remember that while having better battery life in the transmitter would be great, the reason it is a sealed unit is not a money grab. It is because it needs to be a completely sealed unit since it is worn in all conditions like shower or swimming etc. Any water or moisture working its way into the unit would cause failure due to the sensitive nature of the measurements being taken.
I do applaud your drive though and see nothing wrong with trying to make something better. :slight_smile:
Perhaps a panel that is secured by micro screws and has an o ring to seal it would allow for your goals without adding much cost. You could use a 3d printer for this and treat with an acetone bath to smooth out the material so that it doesn’t get caught on anything and comfort and profile are retained.
Sending the signal to a receiver of your own making is simple enough thanks to the Dex Drip system. I recommend you look into that as well.

Hey Terry, thanks for the suggestions in the wording, I changed it to sensor transmitter.

Wow, first response and already have an offer to get a transmitter, this is awesome! I will send you a message.

Hey Ryan,

Sounds like you've got a lot going on as well. Maybe you could help at some point with some programming. I know how to program, but I'm by no means a wizard at it. I'm actually a mech eng guy who out of no where started designing electronics. I mean I have always been interested in them, but was mostly in the CAD design spectrum of things. Now I'm both.

Yeah, I have looked at a few discussions on hacking them open. I especially liked the "Grinder" method that takes out the battery so you can slip in another CR2032. That was clever.

I have a little experience with more finesse when it comes to reverse engineering, or opening sealed cases, so I will see what I can do.

The idea would to make a method and a case for people to do it themselves, all open source, no patent infringement because nothing of theirs is being sold for profit. At least thats how I see it. ha

Yes I agree being sealed is very important, and you pretty much answered the question yourself. O-oring, tight tolerances. But the good thing is with coin cell batteries, they're not to finicky when it comes to moisture. Unless you dunk them in salt water they aren't going to do much. So if the component part of the transmitter is completely sealed off from the battery, using something permanent, then that should suffice in terms of keeping things happy. I will have to get a sensor in my hand to know for sure whether this whole thing will be possible or not.

I know there will be people out there who would think its a bad idea, and that is fine with me, but the point would be to give other options, that is what I like about it. They can take the instructions and their old sensor, and make one.

See the plastic housing for the picture I posted above of the glucose meter? Thats a 3D printed part I designed and had printed in Nylon using an SLS method of printing. I get them printed at Shapeways. I haven't tested how water resistance the material is yet though.

I'm going to look into that Dex Drip system now.

Sounds like you and I have a few interests in common. :)

I also would like to throw my hat in the ring to help something like this along the way.

Wow, neat idea Sean! I will certainly be interested in buying one when they are available! I agree with you on the pricing of the Dexcom gear too, it seems amazing insurance companies aren’t able to negotiate more effectively but I suppose that there’s some sort of patent law that protects profits for them, along with their product?

Do you plan to sell this? If so, do you also plan on obtaining FDA (and other country's similar agency) approval for this medical device?

I hope one day I will create something that is beneficial to everyone, as well as available to them. Its one of those markets that is so selective, and isolated due to the FDA process that what they can charge is their choice between who will buy and what will make money. I'm sure its a seriously complicated system 90% in their favor.

I guess that would be the idea, long in the future. I feel like in order to get FDA approval one must spend millions testing and proving its validity. Right now the idea to get around that system would be to develop each aspect of the monitor in their own individual components, circuit board, casing, software, and make all of them open source. Free in a sense. If you want to buy a finished board off me then you could, but you would have to get the case separately and put it together yourself. If you want to build everything yourself, you wouldn't even have to get in touch with me, I would have no idea. An example of this is the PIDDYBOT I developed. Every so often I get an email from someone across the world saying they made one and they love it and thank me for making it. Of course this project is just the infancy of development - basically planning stages. Like I said, anything I develop right now would be for myself - not profitable - and because I would make the files available as I go, then people could make their own. Ill admit, being a Masters student leaves me with very little money. Luckily for me, I don't enjoy going out, drinking, spending money on wasteful things. Majority of my money goes into my passion, my projects(and the occasional movie with my girlfriend) and I love living this way. Its the only way to get ahead while loving what I'm doing as well. To answer your question directly, yes I would find ways to sell certain aspects of my project(this isn't the only thing I'm working on) to build up my company to do more in general.

I suggested to Dexcom that they develop a transmitter with a rechargeable battery and an induction charger, similar to what is used in the totally sealed Philips Sonicare Toothbrush. A Transmitter kit could include two rechargeable transmitters and one inductive charger. The idea would be that while wearing one transmitter, you could be charging the other. You would swap transmitters when changing the sensor.

The cutting open and replacing battery idea looks like a one shot deal, when the second batteries die, that may be the end of the device. So how about instead if inserting batteries, insert two wires fill with glue and have an external watch battery compartment.

Is the idea to use this transmitter with your alternative sensor?

Yeah that is the way it should be. Wouldn't even really need inductance since I'm sure there are pins of some sort in the bottom to connect to the sensor which could also be used for charging the battery as well.

Yeah the cutting open is definitely a one shot thing, unless you want to cut into your replaced battery Ha. Really at this point everything is experimental, I will most likely try and figure out the best way to remove the battery in the old transmitter and show the process and from there people could really do whatever they want. I will probably start first by trying to redesign their transmitter shape and then see if I can add the addition of a replaceable battery and have it plug back into the Dexcom sensor. Wires would be simple too.

The transmitter will not be used with the different systems I mentioned in the original post, since I can easily add bluetooth to those and have them connect to a phone, or anything really, even wifi. So this will be for people who want to maybe not buy multiple transmitters, or maybe they don't even want to buy the receiver! Since DexDrip is available thats also a possibility.

Look at the Medtronic CGM, it’s rechargeable, 20 minute charge for at least six days of operation.