Data Sheet

This device and software, and any companion software developed for use with it,
MUST NOT be used for making therapeutic decisions about diabetes management.
Always use your standard Blood Glucose devices and management strategies. This
is for informational and experimental use only.
The original wixel code for XDrip was based on work by Adrien de Croy, Lorelai Lane, and
others, but it has some limitations. This bridge code has the following features to address
these:
 Does not receive any Dexcom packets until it has been given a Dexcom G4
Transmitter ID to filter on. This is important to ensure that it correctly locks on to the
signal of the transmitter in question, and only passes that Transmitter ID’s data to
the phone app. IMPLEMENTED (v2)
 Stores the Transmitter ID in flash, so that it survives if power fails for any reason.
The app does not need to reset this in such an event. IMPLEMENTED (v1)
 Sends a “beacon” to the app when it wakes up from low power mode, indicating the
Transmitter ID it is filtering on. The app can either send a TXID packet if the
Transmitter ID the wixel should be filtering on is incorrect, or ignore the beacon.
This is necessary to ensure that when a patient changes their transmitter, the app
knows when the wixel is awake so it can be sent a new TXID packet. Normally, the
wixel will wake up 5 minutes after the previous good packet and stay awake until it
receives a packet from the Dexcom transmitter it is configured to filter on.
IMPLEMENTED (v2)
 Sends a “beacon” to the app every 5 seconds if the code is newly installed and the
wixel has NOT received a TXID packet. It will continue to send beacon packets at 5
second intervals until a TXID packet is received and the Dexcom transmitter ID is
saved to flash. The beacon will indicate the ID to be zero, and the app, once
configured with a Dexcom Transmitter ID, must send a TXID packet before the code
will start accepting packets. The wixel will respond to the TXID packet with a
“beacon” packet indicating the TXID that is set in flash on success. IMPLEMENTED
(v2)
 Accepts a Transmitter ID packet from the phone app, and saves it to flash. Note, the
phone app must await either a data packet or a beacon packet before determining if
the Transmitter ID is incorrect, and sending a TXID packet to the bridge.
IMPLEMENTED (v1)
 Sends the Bridge battery capacity percentage, determined from the battery voltage,
as part of the data packet. IMPLEMENTED (v2)
 Automatically corrects the packet “listen window” for changes in overall program
cycle time. This ensures that any changes to the code does not require any further
experimentation to the listen window to make it work reliably. NOT YET
IMPLEMENTED
 Sets the HM-10 module’s BLE ID to “XBridgeXX”, where XX is the least significant
byte of the wixel serial number. This ensures that each bridge has a reasonably
unique ID, making the BLE connection to the phone running the app more reliable.
IMPLEMENTED (v2)
 Will not sleep if the wixel is connected to a PC USB port. This allows
experimentation or re-scanning for the BLE device by an ap, if for any reason it is
lost or the app is replaced, while the bridge has been programmed with a transmitter