Data Sheet

a. BLE GATT connection series of messages.
b. Messages indicating Receipt of a Beacon Packet.
c. Message saying the Beacon Packet is Wrong.
d. Message “sending message”.
e. Receipt of another Beacon Packet, which is the acknowledgement to the
previous one.
4. The wixel will now listen and wait for a Data Packet. There is no ADB log entry
showing this listening phase, but there will be log entries when a Data Packet is
found.
Test 2 – Reception of Dexcom Data, and initiating sleep.
1. Observe the ADB logs until a message appears showing the reception of a Data
Packet. Note, if you are using Android Studio, you can filter on the
DexCollectionService to more easily find these.
2. Once this message is received, it will be followed by a “sending message” entry.
This is the Data Packet ACK message, and will put the wixel to sleep.
3. A series of messages showing a disconnection of the BLE GATT, and reconnection
to the BLE device. This occurs even though the HM-1x module is asleep.
Test 3 – Waking of the wixel and reception of Dexcom Data.
1. Observe the ADB logs until a series of messages appears showing the BLE GATT
connection taking place. Note, whilst you would assume this happens at very regular
intervals, this is not always the case. It does not mean that the wixel has not woken
as expected, nor that it has missed a packet of data. The BLE implementation does
not automatically detect when a paired device becomes available again.
2. At some time after the BLE connection is established, the ADB logs will show
reception of a Data Packet as per Test 2 above. Depending on timing, it may also
show reception of a Beacon Packet, which will only be dealt with if the TXID is NOT
what the app is expecting.
3. The wixel will return to sleep as per Test 2 above.
Usage Notes
There are a few things to keep in mind when using xBridge code, and many of these will
apply to using the xDrip-wixel code as well.
1. Charge the bridge when battery capacity falls to 40% or lower. Because we are
using a simple battery voltage measure to determine capacity, and LiPo batteries
deplete rapidly as they approach minimum voltage lever, it is best to charge it around
this point rather than wait. While you may get a few more hours out of the battery at
this level, it certainly won’t last a too long.
2. Keep the bridge close to you. While BLE has a bit better range and reliability than
the proprietary 2.4GHz protocol used by the Dexcom transmitter, you will still need to
keep the bridge within the 20’ / 6m radius of it.
3. Currently the bridge will occasionally miss packets. I am still researching why this is
the case. If you use a Qi pad to charge your bridge, this will occur more frequently,
likely due to the electro-magnetic field interfering with the Wixel receiver.