Dexcom G4/G5 transmitter

[mark2]

Hi,
I've been looking into CGM because my Hb1Ac is up to silly levels, and I really need to get things back under control.

I'm particularly impressed by what I've read about the Dexcom CGM system. IT could change everything if it works as advertised. Unfortunately, I just learnt from my doctor that if I wanted to use it I would have to fund it myself...which would be extremely difficult/impossible as things stand. Paying hundreds of pounds for a transmitter every 3 months because you cannot change the batteries is just not on the cards at the moment.

BUT, I have discovered some heroic initiatives that could 1) help to reduce the recurring costs and 2) allow you to manage your own data privately.

I'm a bit of a techie, so I'm imagining 3D printing a new casing/enclosure which would allow you to replace the transmitter batteries, with a proper screw down top and watertight seal. This would leave me paying for the sensors, which I could just about manage financially (if you can really get them to last for 3 weeks as some people claim).

So, to get to the point : I'm looking for some used Dexcom G4(slim model) or G5 transmitters that I could chop up. I would be happy to pay for them and/or share any useful results of my efforts.

It would be great if anyone here who is using the Dexcom system could help out with this.

Mark

 

[Chas C]

Mark - I'm sure your an honest person, but recently there have been issues with some unscrupulous people making similar claims for expired transmitters and then replacing the batteries and reselling them.

I do indeed like your thoughts but you need to think how you can build some initial level of trust/openness with those supplying you transmitters.

I wish you well and look forward to seeing the results.

 

[mark2]

Chas, I fully understand the issues you mention. I had already noticed that someone is trying to sells gunk covered transmitters on Amazon.
Indeed, before posting this I have been scouring commercial sites like ebay, where I would be perfectly happy to buy them.
Unfortunately, while there are some new dexcom supplies available on ebay, nobody seems to be selling used transmitters, at the moment at least. Maybe there will be some in the future.
In any case, I'm not looking for an endless supply of used transmitters, 3 or 4 should do the trick, allowing for 'accidents' in cutting into them.
Other than offering to share the results of any work (successful or otherwise), I see little else that I can do at this stage except hoping that someone will give me the benefit of the doubt.
Thank you for your input, and yes I'd be happy to keep you informed.

 

[GrantGam]

The best route for you to go down @mark2 would be to buy a transmitter and sensor(s). Firstly, it'll let you know whether the Dexcom system is for you or not -through actually being able to use the CGM. Secondly, you'll then be able to butcher your own expired transmitter once functionality has elapsed.

It would be great to get an expired transmitter from another user, but you may be waiting a while for the reasons that @Chas C has stated.

I think you'll probably manage to cut into a transmitter and change out the batteries first go. There are a few videos on YouTube of the procedure and providing you go about it with a reserved approach; you shouldn't run into difficulties.

I must say though, a 3D printable enclosure for a transmitter would be pretty clever. However, it may add substantial bulk to the CGM - but that may be something that you've already planned to overcome.

Good luck to you either way. Making CGM more affordable for the users is a MUST. And is unfortunately something that the manufacturers are not overly concerned with for obvious reasons.

 

[mark2]

I think you'll probably manage to cut into a transmitter and change out the batteries first go. There are a few videos on YouTube of the procedure and providing you go about it with a reserved approach; you shouldn't run into difficulties.

I must say though, a 3D printable enclosure for a transmitter would be pretty clever. However, it may add substantial bulk to the CGM - but that may be something that you've already planned to overcome.

Thanks for the advice @GrantGam1337 .
However, I actually don't want to do the same thing that is on the YouTube videos and end up with a one-off, workable solution. What happens when you need to change the batteries again?
I'd like to explore 2 approaches:
1) getting the PCB out of the original plastic completely and design a completely new enclosure. Could be tricky.
2) using a milling machine to remove a precise amount of material off the top so that I can 3D print a new lid.
Either way, it's unlikely that I'd get it right first time.

After @Chas C, you are the second person to bring up the trust issues. Apart from the risk that I may turn out to be a shyster out to make a few quid on each unit, I fail to see a major downside for the seller in these days of PayPal. Am I missing something here, concerning the potential risk to the seller?

 

[GrantGam]

Thanks for the advice @GrantGam1337 .
However, I actually don't want to do the same thing that is on the YouTube videos and end up with a one-off, workable solution. What happens when you need to change the batteries again?
I'd like to explore 2 approaches:
1) getting the PCB out of the original plastic completely and design a completely new enclosure. Could be tricky.
2) using a milling machine to remove a precise amount of material off the top so that I can 3D print a new lid.
Either way, it's unlikely that I'd get it right first time.

After @Chas C, you are the second person to bring up the trust issues. Apart from the risk that I may turn out to be a shyster out to make a few quid on each unit, I fail to see a major downside for the seller in these days of PayPal. Am I missing something here, concerning the potential risk to the seller?

The batteries can be changed again, it would just involve cutting through the epoxy resin or whatever adhesive you had used to seal the "lid" on to your transmitter. And you'll more than likely get more than three months out of the batteries. This would probably be a twice yearly job, maybe even less!

Tbh, you wouldn't need a milling machine to remove the top, you'd probably have more luck and accuracy with a fine abrasive wheel on the end of an battery drill or dremmel.

It's not a trust issue @mark2, not from my standpoint anyway. But what you may find is that people will be unlikely to part with their old transmitters simply because they've had to pay a lot of money for them. If I had something expensive that was going in the bucket, I'd pass it on. I'm afraid a lot of people don't think the same way unfortunately.

 

[iHs]

Thanks for the advice @GrantGam1337 .
However, I actually don't want to do the same thing that is on the YouTube videos and end up with a one-off, workable solution. What happens when you need to change the batteries again?
I'd like to explore 2 approaches:
1) getting the PCB out of the original plastic completely and design a completely new enclosure. Could be tricky.
2) using a milling machine to remove a precise amount of material off the top so that I can 3D print a new lid.
Either way, it's unlikely that I'd get it right first time.

After @Chas C, you are the second person to bring up the trust issues. Apart from the risk that I may turn out to be a shyster out to make a few quid on each unit, I fail to see a major downside for the seller in these days of PayPal. Am I missing something here, concerning the potential risk to the seller?

I'm not sure on this, but looking online at the new G6 transmitter that looks to have the battery under the circle well at the end, also looks to be inserted into a new type of shoe on the sensor. If this is the case, then as the transmitter for the G4 is only guaranteed for 6 months and the sensor should be replaced every 7 days, a lot of people might well come unstuck and will no longer be able to use the existing G4 and G5 transmitters if the sensor shoe changes shape.

 

[mark2]

The batteries can be changed again, it would just involve cutting through the epoxy resin or whatever adhesive you had used to seal the "lid" on to your transmitter. And you'll more than likely get more than three months out of the batteries. This would probably be a twice yearly job, maybe even less!

Tbh, you wouldn't need a milling machine to remove the top, you'd probably have more luck and accuracy with a fine abrasive wheel on the end of an battery drill or dremmel.

It's not a trust issue @mark2, not from my standpoint anyway. But what you may find is that people will be unlikely to part with their old transmitters simply because they've had to pay a lot of money for them. If I had something expensive that was going in the bucket, I'd pass it on. I'm afraid a lot of people don't think the same way unfortunately.

Thank for the suggestions @GrantGam1337 . I am lucky enough to have access quite a bit of equipment to do this in a "clean" way, including a 3D scanning rig, 3D printer and a milling machine, hence my ideas of how best to proceed. I'd like to avoid using any adhesive at all, using small screws and a proper gasket or O-ring instead.

I'm quite optimistic about eventually getting my hands on a couple of used transmitters, they seem to come up for sale from time to time .

 

[mark2]

I'm not sure on this, but looking online at the new G6 transmitter that looks to have the battery under the circle well at the end, also looks to be inserted into a new type of shoe on the sensor. If this is the case, then as the transmitter for the G4 is only guaranteed for 6 months and the sensor should be replaced every 7 days, a lot of people might well come unstuck and will no longer be able to use the existing G4 and G5 transmitters if the sensor shoe changes shape.

Yes, it might not be possible to do a similar operation on the G6 version, which I understand will probably be released next year. We will have to wait until then (+ >3 months) to see what hacking possibilities this new device could offer, or prevent.
I think I should be aiming to start with the G5 rather than the G4 because you don't need the hardware wireless bridge for the G5, which can connect directly to XDrip on the phone.