xDrip and xBridge Build Instructions

A naked xBridge

I have been meaning to make this post for some time as I always struggled to find clear and easy to follow instructions on how to build an xDrip or xBridge devices. For me battery life and size are key, therefore this build uses a high capacity battery and fits a small form factor of a Tic Tac box.

These devices listen out for the signal from a Dexcom G4 CGM and relay via Bluetooth to your mobile phone with the xDrip app installed. xDrip is my CGM source that I sync directly to HAPP and Nightscout.

Parts

You should already have

Common Parts

xBridge only

 

xDrip or xBridge?

xBridge is an extension from the original xDrip design that also provides battery level readings and power saving features. 

What one should you build? Both!

While it's great to have the power saving features and battery level data from xBridge, it's nice to have a second unit in the event of issues and troubleshooting. Out of the two xDrip is easier to build, I suggest starting with an xDrip first.

 

Let's Build!

Step 1 - It's all about size

We need to remove unnecessary connectors from the Bluetooth module and Adafruit charger. This can be done by heating the solder points and pulling the pins out with some pliers, I recommend removing the plastic parts on these pins first. The end result should look like the below...

Charger with unneeded parts removed
Charger with unneeded parts removed

 

Bluetooth Module with unneeded parts removed
Bluetooth Module with unneeded parts removed

 

Step 2 - Charger, Switch & Battery

Far too many times I have seen the battery soldered direct to the charger, while this is compact it means there is no way to restart the device - this is useful especially when troubleshooting.  

Below is a Circuit Diagram for adding the switch and battery along with a photo example. Note that the switch is connected directly to the Charger to save space, its 3rd leg is soldered to the screw hole to make it more secure. 

Charger--Switch-Circuit-Diagram
Gray line is Solder in this image
Charger--Switch
Note that for the BAT cable from the switch I have added a little heat shrink

 

Step 3 - Circuit Diagrams

This differs for each device, see the Circuit diagram below for the device you are making for the layout. I strongly suggest that you use the same cable colors I used, also I have provided images of my build process to see the device built stage by stage.

Start with the Wixel and Bluetooth Module first, while we want to keep the joining cables short, be sure to leave a few millimeters spare as "wiggle" room. 

Then the Charger and Switch, here we need a little extra slack in our cables so that we can maneuver the charger and battery when placing inside the Tic Tac box.

A: xDrip

xDrip-Circuit-Diagram
xDrip-Circuit-Diagram from xDrip GitHub page
xDrip-Wixel
Wixel with all cables attached 
xDrip-Wixel-Back
Wixel back
xDrip-no-Charger
Wixel and Bluetooth module attached
xDrip-Open
Final xDrip

B: xBridge

 

xBridge-Circuit-Diagram
xBridge-Circuit-Diagram from xBridge GitHub documentation 
xBridge-Wixel-adding-Resistors
Adding the 10k Resistor
xBridge-Wixel-adding-Resistors
Adding the 10k Resistor
xBridge-Wixel-adding-Resistors
Note the item in the black heat shrink is the 27k Resistor
xBridge-Wixel-with-Resistors
All Resistors added
xBridge-Wixel-Front
Wixel with all cables attached 
xBridge-Wixel-Back
Back of Wixel 
xBridge-Wixel--Bluetooth
Wixel attached to the Bluetooth Model
XBridge-Open
XBridge with Charger, just the Battery connection to be done

 

Step 4 - Firmware & Test

We are almost ready to rock, but first we need to load the correct firmware onto our Wixel. We need the Wixel Configuration Utility to load the firmware, once installed plugin your Wixel with the mini USB cable and install one of the following firmware. You can install the firmware once downloaded by double clicking it, this will load the Wixel Configuration Utility.  

A: xDrip

Each xDrip firmware has the Transmitter ID hard coded into it. The best way to build a new firmware with your Transmitter ID is by using the xDrip Kit Wixel Firmware Generator.

B: xBridge

xBridge firmware can be downloaded directly from Github, right click "xBridge2.wxl" and save it to your computer. 

xBridge has a power saving feature that turns off the Bluetooth connection to your phone between readings, some phones have issues with this and struggle to pair again with the xBridge resulting in missed readings. Personally, I turn this feature off by following the below steps...

  1. Download Putty, we will use this to connect to the Wixel
  2. Connect the Wixel to the computer and open the Wixel Configuration Utility. Note the COM port the Wixel is connected to, now close Wixel Configuration Utility
  3. Open Putty, pick Serial and enter the COM port you noted earlier. Click the button "Open" to connect to the Wixel
  4. Once connected copy and paste the following letters and then pressing enter...
    1. B - Turns off Bluetooth sleep
    2. S - Will show you the Wixel config, this will confirm 

 

Step 5 - Tic Tac it home

To protect the battery from any sharp protruding parts from the circuits I suggest placing a thin piece of plastic between them, anything will work for example a yogurt pot lid. Position the parts as shown in the image below, you should have enough slack cable from the Wixel to charger and charger to the battery to help position things, once in place the Micro USB charging port should line up exactly with the lid of the Tic Tac box.

xBridge-Without-Tic-Tac-box
xBridge-Without-Tic-Tac-box

 

xDrip--XBridge-Tic-Tac
xDrip and XBridge

 

Step 6 - Software Configuration

In xDrip or xDrip+ pick the correct "Hardware Data Source" for the device you have built. 

xdrip-data-sources
xdrip-data-sources

xBridge Only

In xDrip or xDrip+ set your Transmitters code. 

xbridge-transmitter-id
xBridge-transmitter-id

 

Credits

 

 

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Disclaimer

The contents of this site is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your Diabetes support team or other qualified health provider with any questions you may have regarding your medical condition.Sorry, have to say something like this!