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Tag Archives: cgm-in-the-cloud

Wire free charging for your xDrip

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NOTE: xDrip used to be called DexDrip so you might find some references to the old name in this article.

 

Qi

I’m slightly jealous at the moment…

Andrew Abramowicz wanted to take his xDrip to the next level, so he made another one with inductive charging using the Qi wireless receiver module from Adafruit. He increased his battery size to 2000mAh which is roughly the same size as the charging module, which is a little on the delicate side.

Watch this video of how to connect the module up:
httpv://www.youtube.com/watch?v=-KQeLmrH2B8

PLEASE READ THIS ADVISORY

a) Never make a medical decision based on a reading from any CGM device, whether certified (eg Dexcom) or not (eg xDrip). Always perform a fingerstick blood glucose check first.
b) xDrip is a DIY product, decide for yourself if you wish to use it. Build it, test it, test it again and use (if you want to) in conjunction with a certified receiver.
c) The fact that it is working for us does not mean it’s right for you.
d) Never build a xDrip for anyone else and never sell one.
e) The blogs are provided for information only. We are not endorsing it for use by others, nor promoting it, just merely publishing our information as well as answering questions from previous blog articles.

xDrip Test Results (vs Dexcom’s 505 algorithm)

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NOTE: xDrip used to be called DexDrip so you might find some references to the old name in this article.

 

xDrip comparison - overviewA graph from a Nightscout website showing
results from Dexcom and xDrip data

Many people have asked questions about the accuracy of xDrip’s algorithm in comparison to the latest Dexcom G4 algorithm, codenamed 505.
To answer this question for himself Andrew Abramowicz decided to get xDrip and an original Nightscout rig to upload data to the same database at the same time, with both sets of data coming from the same Dexcom G4 sensor/transmitter. This then is a true test of how things worked for Andrew and his family. Thanks Andrew for allowing me to use this these images on this page.

PLEASE READ THIS FIRST

a) before using xDrip for prime time use, run these tests for yourself.
b) if you don’t calibrate properly your results may vary, correct calibration is the key.
c) while these results mimic that of the 505, it is still an “experimental algorithm” and should be used with great caution.
d) as (c)…but to add…’especially in children’.
e) before using xDrip decide for yourself if it is good enough for you based on your own tests
f) we are not “endorsing” it for use by others, just publishing our findings.

NOTE:You can click on most of the images to view the full image in your browser.

A little background bit on the data, which you can probably skip
Andrew’s son wears a Dexcom G4 CGM sensor and transmitter and for a while has used a Nightscout uploader rig to send CGM data to the cloud to be viewed on a Nightscout web site.
Andrew recently built a xDrip device, which can also upload its data to the cloud to be viewed on a Nightscout web site.
The Dexcom G4 receiver (which is part of the uploader rig) and the xDrip both read the same data from the same Dexcom transmitter and sensor.
Both are loading their data up to the same cloud database which is then linked to the same Nightscout web site.
Data from both is overlayed together, allowing for an easy visual comparison and ultimately to see any discrepancies.
What’s all those strange low numbers?
If you’re used to seeing much higher numbers – perhaps you live in the USA? – then don’t panic, the glucose values show are in mmol/l because Andrew is in Canada. To work out a mg/dl value from a mmol/l value just (!) multiply any numbers by 18, so 5mmol/l is 90mg/dl, 10 = 180 etc.
An explanation of a Nightscout website graph

The image below is of Andrew’s Nightscout website. For those who have never seen one before here’s an explanation of what is shown.
Top left is the time ’10:50′ and showings that the last CGM data received happened 1 minute ago.
Top right is the last CGM reading of 7.2mmol/l (129.6mg/dl) and this has stayed the same from the previous reading.
On the right is the range axis, showing 22mmol/l at the top and 2 at the bottom.
The dots show show the glucose readings, with green dots being actual readings and blue dots being projected readings.
The rightmost green dot is the last reading of 7.2mmol/l from one minute ago.
The rightmost green dot is actually two dots, one for Dexcom, one for xDrip but they are both the same value.
The first reading shown on the left shows that there was a difference between Dexcom and xDrip of approximately 0.4mmol/l (7mg/dl).
The two red dots on the left are where a calibration has taken place, one for Dexcom, one for xDrip.
xDrip comparison - spot on
More explanations
Here’s a visual explanation

xDrip comparison - chart 1
Comparison overview
Here’s an image showing how close xDrip and Dexcom are for the majority of the time.

xDrip comparison - overview
An overnight test
The next image is of an overnight test showing a hypo in the middle. During the hypo the variance was the largest Andrew has ever seen, before the correction with glucose it looks to me to be about 0.4 mmol/l out, straight after the correction either Dexcom or xDrip appears to have gone wildly out for one reading.
However, no-one I know would rely on CGM data anytime near a hypo situation and never should any treatment been done with first taking a finger prick blood glucose test.

xDrip comparison - hypo - big difference (0.5 mmol!)
At the end of an overnight test
Although there hasn’t been a calibration for 10 hours values are almost exactly the same, maximum out is 0.4mmol/l (7 mg/dl).

xDrip comparison - overnight without calibration
A 48 hour trace
The CGM trace below shows a trace over 48 hours – you can scroll left/right.
At times you can see there’s a difference, potentially 1 mmol/l out at maximum point.
Upper line is at 8mmol/l (144mg/dl), lower line is at 4mmol/l (72mg/dl). Red dot indicates a calibration.
Click here if you want to view the full image

xDrip comparison - 48 hours
Distance test
Here’s a test placing the xDrip at different distances away from the transmitter, showing that at 25 feet it ability to receive data is impaired, yet at 10 feet it is perfect.

xDrip comparison - distance
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PLEASE READ THIS ADVISORY

a) Never make a medical decision based on a reading from any CGM device, whether certified (eg Dexcom) or not (eg xDrip). Always perform a fingerstick blood glucose check first.
b) xDrip is a DIY product, decide for yourself if you wish to use it. Build it, test it, test it again and use (if you want to) in conjunction with a certified receiver.
c) The fact that it is working for us does not mean it’s right for you.
d) Never build a xDrip for anyone else and never sell one.
e) The blogs are provided for information only. We are not endorsing it for use by others, nor promoting it, just merely publishing our information as well as answering questions from previous blog articles.

A Dummy’s Guide to Building an #xDrip – #WeAreNotWaiting

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NOTE: xDrip used to be called DexDrip so you might find some references to the old name in this article.

 

If you don’t know what a xDrip device is take a look at this page.

AdaFruit charger magnifiedI was tickled by someone on Reddit who linked to yesterday’s blog about the components required for a xDrip which was entitled “An “Amateur” builds a module for DexDrip”. So here it is, this amateur’s guide to building an xDrip/DexDrip. (The article actually referred to DexDrip as that what xDrip was called at the time.)

Interested in further posts about this subject? Why not like this blog’s Facebook page and get notified of updates, or click ‘Follow’ using the button at the bottom-right of this page.

PLEASE READ THIS ADVISORY

a) Never make a medical decision based on a reading from any CGM device, whether certified (eg Dexcom) or not (eg xDrip). Always perform a fingerstick blood glucose check first.
b) xDrip is a DIY product, decide for yourself if you wish to use it. Build it, test it, test it again and use (if you want to) in conjunction with a certified receiver.
c) The fact that it is working for us does not mean it’s right for you.
d) Never build a xDrip for anyone else and never sell one.
e) The blogs are provided for information only. We are not endorsing it for use by others, nor promoting it, just merely publishing our information as well as answering questions from previous blog articles.

A baptism of fire heat
Although I received lots of offers of help to solder the components together the guys at work told me I’d have no trouble doing it myself, so I decided to try.
First I ordered the soldering kit (iron, solder, stand, helping hands, solder sucker) from eBay and a practice board to train myself with. The ‘helping hands‘ turned out to be worth their weight in gold.
I soldered my first pin, inspected it and then soldered three more, choosing to solder them right next to each other as it seems that a common problem for amateurs is putting too much solder on. With four pins soldered I tested everything for continuity issues, to make sure no excess solder had spilled on to the adjacent contacts and shorted anything out.

practice board face uppractice board face down
So far, so good.
AdaFruit LiPo charger and batteryAttach LiPo-charger connector to battery
My AdaFruit LiPo-charger came with a connector, my battery came with a connector; they weren’t the same.
First job then was to cut the wires from each and solder the battery wires to the LiPo-charger connector.
NOTE: some people remove the connector terminal on the LiPo-charger and solder directly onto the charger board, I didn’t fancy this as I like to be able to disconnect batteries and swap them easily.
DO NOT connect battery to LiPo-charger.
AdaFruit charger magnifiedSolder wires to AdaFruit charger
The AdaFruit Li-Po battery charger then needed a power (red) and ground (black) wiring up.
For my first try I soldered a four-piece-header-pin to the board and used jumper wires to connect to it, but within a week I removed the header pins & soldered the wires directly onto the PCB.
1. Red wire, solder on to 3.3v (marked as BAT on mine), first on the left as we look at that board. Make sure you don’t solder on to the 5v connector.
2. Black wire, solder on to one of the GND connectors, for ease I chose the 3rd from the left.
WIXEL bluetooth wiresConnect wires for bluetooth module to WIXELWIXEL face down
Prepare four wires (red, black, green, blue) with one female header pin at one end and bare wire for soldering at the other.
1. Black, solder to GND
2. Red, solder to 3V3
3. Blue, solder to P1_6
4. Green, solder to P1_7

Other possible options: The header pin option is the simplest way to connect from WIXEL to HM-10.
The hardest (but not too bad) option is to desolder the HM-10’s header pins, then solder wires with two bare ends onto the WIXEL and to the HM-10.
The middle option is to solder wires with two bare ends, one end onto the WIXEL and one bare end onto the relevant header pin on the HM-10. Whilst this might seem easy I think it’s simpler to desolder the HM-10s header pins as above.

WIXEL and BLEConnecting the HM-10 Bluetooth moduleBLE face down
What you do next depends on what you chose to do on the ‘Connect wires for bluetooth module to WIXEL’ step:
If you soldered wires with female header connector at one end when you did the step above then all you need to do next is to slide the correct colour wire’s connector onto the correct HM-10 pin as per the diagram here.
If you soldered wires with two bare ends and left the header pins on the HM-10 then you need to solder the bare wire ends to the correct HM-10 header pin as per the diagram here. This is tricky to do (for me) but not impossible as I found when I made a second xDrip. I choose to wrap electrical tape around each soldered pin/wire afterwards.
If you soldered wires with two bare ends and removed the HM-10 header pins then just solder the bare ends onto the HM-10 as per the diagram here.
WIXEL power wiresSolder LiPo-charger wires to WIXELWIXEL face down
With the LiPo-charger disconnected from the battery (and micro-USB power) you now need to solder its wires to the WIXEL.
Red, solder to VIN
Black, solder to GND
 
The finished product
Hopefully by the end of it you’ll have something that looks like this:
20150109_205710
Note: the picture shows header pin connections for the AdaFruit Li-Po charger but I’ve now soldered the wires directly to the board, it now has a much smaller footprint.
 
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#WeAreNotWaiting thanks to #xDrip – Components Required

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NOTE: xDrip used to be called DexDrip so you might find some references to the old name in this article.

 

If you don’t know what a xDrip device is take a look at this page.

partially made up xDripSince the release of my first comment about xDrip on Sunday morning my Facebook and Twitter notifications have gone crazy: ‘like’s everywhere, comments everywhere, questions everywhere. At stages I’ve been overwhelmed with my phone buzzing with notifications ten to the dozen and me not getting the time to answer the questions. This just goes to prove the level of interest in a set up like this.

By far the biggest questions I have been asked are:
    1. can I really build this myself as I’ve never soldered before?
    2. what components do I need?
    3. where can I buy these components?

The answer to 1 is easy: Yes, you probably can, I had never soldered anything electrical before starting this project, in fact I had to buy a soldering iron/kit just for this.

The rest of this blog should answer questions 2 and 3.

Interested in further posts about this subject? Why not like this blog’s Facebook page and get notified of updates, or click ‘Follow’ using the button at the bottom-right of this page.

PLEASE READ THIS ADVISORY

a) Never make a medical decision based on a reading from any CGM device, whether certified (eg Dexcom) or not (eg xDrip). Always perform a fingerstick blood glucose check first.
b) xDrip is a DIY product, decide for yourself if you wish to use it. Build it, test it, test it again and use (if you want to) in conjunction with a certified receiver.
c) The fact that it is working for us does not mean it’s right for you.
d) Never build a xDrip for anyone else and never sell one.
e) The blogs are provided for information only. We are not endorsing it for use by others, nor promoting it, just merely publishing our information as well as answering questions from previous blog articles.

Components you’ll need to buy, borrow or steal
(Okay, don’t steal, that’s not good.)
Thank you to Johan Lorant from the USA for information about the components he bought.

HM10 v CC41UPDATE WARNING
It seems there’s two types of chip being passed of as HM10, the second actually being a CC41 and it appears these will not work, although some do.
Be careful which one you get, check with the supplier before you order one but bear in mind that that supplier will only know what their supplier told them. Best thing is to get a proper photo of them beforehand and make sure it’s a HM10 as per the picture on the right.
BLE face upBluetooth Low Energy 4.0 BLE Tranceiver HM-10 Module
From eBay seller AudioSpectrumAnalyzers I’ve got a working HM10 (see warning above), in fact he even has ‘xdrip’ in the items listing title. Cost: under £12.
The first one I bought was off eBay for £15.29 from Aura Communications.
WIXEL face downThe heart of the xDrip device is the WIXEL chip.
I got mine – along with lots of stuff – from Hobby Electronics.
Cost: £13.80
In the USA, one place to get it from is from Jaycon Systems:
JS-3237 Wixel Programmable USB Wireless Module

AdaFruit LiPo charger and batteryAdaFruit LiPo (Lithium-ion Polymer battery and MicroUSB charger.
I got the charger from eBay for £7.70 each, I bought two. An alternative is Pimoroni at £7.
I got the battery from eBay too, 1200mAh ones, although note that Stephen (the designer of xDrip) only uses a 500mAh battery.
In the USA one place to get from is Jaycon Systems
JS-1965 Micro-USB Lipo Charger (MCP73831)
JS-3418 3.7 Volt Rechargeable Lithium Battery (850 mAh)
jumper-wires-ff-6in-500x500You’ll need some wires to link it all together. I bought these and cut them in half as I’m going to build another xDrip.
Cost: £2
In the USA one place to get these from is Jaycon Systems
JS-3958 Flat Ribbon Cable – 16 Wire (15 Ft) 1
SolderingkitHaving never soldered before I was in need of a few things, all of which I found in this kit. Note that everything works well apart from the solder, buy some good stuff elsewhere.
The ‘magic hands’ and magnifying glass were a Godsend, I couldn’t have done without them.
digital-multimeter-basic-500x500I wouldn’t be without my multimeter when dealing with electrical stuff but you don’t actually need one. I used one for the first xDrip I built but not for the 2nd or 3rd which I use as spares in demos.
Cost: £10 or so, from any DIY or electronic hobbyist store, such as HobbyTronics.
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#WeAreNotWaiting thanks to #xDrip – Introduction

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xDrip logo on left, Nightscout logo on right
As you can see xDrip loves Nightscout
NOTE: xDrip used to be called DexDrip so you might find some references to the old name in this article.

 

Okay, I’ll own up, I know I shouldn’t be so excited about this but I am.
This is a game changer, for us and many, many more.
It proved its worth within 24 hours when I saw Amy was hypo whilst sleeping (see below). Amy wouldn’t have woken up and tested her blood glucose for another 4 or 5 hours but by having xDrip working I saw that she needed some glucose tablets to raise her blood glucose levels. 5 minutes later she was back asleep…for four more hours. #Teenagers!

Interested in further posts about this subject? Why not like this blog’s Facebook page and get notified of updates, or click ‘Follow’ using the button at the bottom-right of this page.

PLEASE READ THIS ADVISORY

a) Never make a medical decision based on a reading from any CGM device, whether certified (eg Dexcom) or not (eg xDrip). Always perform a fingerstick blood glucose check first.
b) xDrip is a DIY product, decide for yourself if you wish to use it. Build it, test it, test it again and use (if you want to) in conjunction with a certified receiver.
c) The fact that it is working for us does not mean it’s right for you.
d) Never build a xDrip for anyone else and never sell one.
e) The blogs are provided for information only. We are not endorsing it for use by others, nor promoting it, just merely publishing our information as well as answering questions from previous blog articles.

partially made up xDripSo what is xDrip?
xDrip is a combination of a device and a software application which receives data sent out by a Dexcom G4 CGM transmitter/sensor and displays the glucose readings on an Android phone. The app can also upload it’s data for use by Nightscout, which in turn means glucose readings are available on the internet via a PC/Mac, phone or even a smart watch (Pebble etc.).
xDrip is made up of two things:
1. The first is a do-it-yourself device, made up of four components which you can buy off the Internet and solder together. Total price is about £40 including battery. (That’s a partially made device on the right).
2. The second is the xDrip application which runs on Android phones (4.3+above with Bluetooth Low Energy (BLE) support). The app uses the xDrip device to read the output from a Dexcom CGM (continuous glucose monitor) sensor/transmitter. xDrip links up to existing Nightscout databases. The xDrip app can feed the data to a Nightscout database, which in turn means the data can be accessed via the Internet practically anywhere, using a PC/Mac, laptop, smartphone (Android/IOS/Windows) or better still a SmartWatch.

Wait! What? Nightscout? BLE? CGM? Dexcom? Animas?
Okay, it’s probably a good time to go over some of the common words I’ve used in the article. I’ll presume you’re already aware of insulin, insulin pumps, glucose levels and the world of Smartphones.
Animas – Animas is a company that makes insulin pumps. My daughter Amy has been using one of their pumps – called the Vibe (yeah, yeah, I know!) – since since June 2013. We chose the Animas Vibe specifically because of it’s use of Dexcom’s CGM system, although it turned out to be a whole year before we got the chance to use CGM.
BLE – is a version of the Bluetooth communication protocol which uses a low amount of energy, which means devices can work for longer without charging. Android has built-in support for BLE from version 4.3 onwards.
CGM – Continuous glucose monitor. A device which regularly samples the glucose level of its wearer, sampling the glucose in the interstitial fluid, not the blood. If you’re new to CGM perhaps take a look at this blog of mine: CGM: we’re live with Animas/Dexcom.
CGM-in-the-Cloud – is a term for any CGM which can be connected to a web site to allow for remote monitoring of someone’s glucose levels. It’s pretty big in USA, not so much over in Europe. A big player in this is Nightscout (see below).
Dexcom – Dexcom is one of many manufacturers of CGM systems. We use Dexcom because it’s linked with Amy’s Animas Vibe pump, if we’d got a Medtronic pump we’d use their Enlite CGM system. One benefit of Dexcom’s CGM appears to be that the sensors last longer – which is a big thing for us (who pay for CGM ourselves) as it lowers the total cost of using CGM. For the record I don’t believe Dexcom is any better than the new Medtronic Enlites.
Nightscout – Nightscout is “an open source, DIY project that allows real time access to a Dexcom G4 CGM from web browsers via smartphones, computers, tablets, and the Pebble smartwatch. The goal of the project is to allow remote monitoring of the T1D’s glucose level using existing monitoring devices.” In short Nightscout and the people behind it are awesome.

Who should we thank for xDrip?
Not me that’s for sure.
xDrip is the brainchild of Stephen Black, who was recently diagnosed with Type 1 Diabetes. With the help from others in the CGM-in-the-Cloud community Stephen has designed the xDrip device and written the software.
I think he deserves a big round of applause.

So how does it work?
SmartWatch

  • Dexcom sensor reads glucose level
  • Dexcom transmitter sends out data from sensor, like a split second radio broadcast
  • The xDrip app (on Android phone/tablet) controls the xdrip device to listen for and receive the Dexcom data.
  • The app displays information about the person’s glucose levels now and over the last day or so, indicating whether it rising or falling or staying level
  • If required the app can upload the data to a Nightscout database. We didn’t do this initially but set it up within the first week.
  • If using Nightscout parents (etc.) can view Nightscout info on a PC/website/smartwatch, like on the right. I’ve seen some great pictures of parents looking at their kid’s glucose level being displayed on the parent’s Pebble watch whilst the kid does some activity with their friends.
  • A further step is the use of another Android/smartphone application named Nightwatch, also written by Stephen. It relays information from the Nightscout data onto a secondary phone and potentially on to a smartwatch.

That’s Stephen’s SmartWatch above/right, showing the glucose levels on mg/dl (so don’t panic UK people).

Stuff you’ll need before using xDrip

  • Dexcom G4 CGM system, including transmitter and sensors.
  • An Android phone or tablet running version 4.3 or above and the ability to use BLE.
  • Components for the xDrip device (Wixel (£14), LiPo battery (£6) and charger (£6), BLE module (£15) and some wires to link it all together.
  • A case to put all the components in. (Yes I really must buy a case soon.)
  • A soldering iron or a friend/relative with one. I bought one off eBay for £12 including the iron, solder, iron stand/sponge and magic hands with magnifying glass.
  • A bit of patience. I didn’t have any but on reflection it would probably be a good thing.

In this next blog I detail the components I bought, which are pretty much the same components Stephen Black (the creator of xDrip) used.

Is this really a do-it-yourself project?
Yes. Definitely.
Before starting on this project I had never soldered any electrical components, I even had to buy a soldering kit specifically for this. Fair enough I program computers for a living but in this case my knowledge actually hindered my progress as I looked for a complicated solution to a problem I didn’t actually have. Luckily Stephen was on hand (via Twitter) to help me through it.
Soldering wise I’d say I spent a couple of hours in elapsed time making up the device, but that’s only because I was taking it very slowly to make sure I got nothing wrong. I’d imagine anyone with soldering experience would have this done in a few minutes.
If you don’t feel you can solder the components together why not ask a friend, relative or colleague?

xDrip's first 'catch'A real life example
With the xDrip device in Amy’s room, we checked that our tablet’s xDrip app could communicate with it when in our bedroom and also when downstairs in the kitchen; it could.
Off to bed we all went, everyone drifting off quick quickly, except me as I was busy staring at a tablet mesmerised by the information in front of me. (I really hope that’s a first night thing!)
At 7am I woke up and went downstairs, taking the tablet with me but not looking at it, placing it on charge in the kitchen, underneath Amy’s bedroom. I heard a noise and presumed it to be a mobile getting a Facebook notification or something. Then it happened again.
I realised it was Amy’s Animas Vibe pump vibrating to tell her that something wasn’t great, it was right she was low. Amy was fast asleep with the pump lying on the mattress beside her, she couldn’t feel it, it didn’t wake her. On the other hand I was in the room underneath and heard it, the vibration going through the mattress, down the bed itself, onto the floorboards, through the joists and onto the ceiling below!
So I checked the tablet and saw the image on the right. I waited 10 minutes to see if her level improved – it didn’t – and went up to wake her to give her a few glucose tablets. Amy went straight back to sleep, I went downstairs happy that she was no longer in danger.
Twenty minutes later I was pleased by the 5.5mmol showing on the xDrip app.

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Interested in what components you’ll need to build xDrip? Then read this: #WeAreNotWaiting thanks to #xDrip – Components Required