xdrip-js

Please note this project is neither created nor backed by Dexcom, Inc. This software is not a product. xdrip-js comes with no warranty or official support. Anyone using xdrip-js is doing so at their own risk and must take responsibility for their own safety. The use of xdrip-js for therapy is not FDA approved and comes with inherent risks.

Prerequisites

Update node version. Please see wiki page for instructions https://github.com/xdrip-js/xdrip-js/wiki

Clients

See Lookout or Logger for two examples of applications built using this library.

Installation

cd ~/src
git clone https://github.com/xdrip-js/xdrip-js.git
cd xdrip-js
sudo npm install

Testing

npm test

Troubleshooting

To make the transmitter communication more reliable, it is recommended to unpair the transmitter from the rig between every read event. bt-device -r DexcomXX where XX is the last 2 digits of the transmitter serial number.

Usage

Example

sudo node example <######> where <######> is the 6-character serial number of the transmitter.

To see verbose output, use sudo DEBUG=* node example <######>, or replace the * with a comma separated list of the modules you would like to debug. E.g. sudo DEBUG=smp,transmitter,bluetooth-manager node example <######>.

Create New Instance

const Transmitter = require('xdrip-js');

// transmitterId is 6-character transmitter serial number
// getMessagesCallback is callback function to return array of messages to send to transmitter
// alternateBluetoothChannel is a boolean to use receiver BT channel if true - defaults to false
const transmitter = new Transmitter(transmitterId, getMessagesCallback, alternateBluetoothChannel);

Events

See Node.js EventEmitter docs for more info on the event API.

Glucose read event

glucose = {
  inSession: <bool>,
  glucoseMessage: {
    status: <int>,                // Transmitter Status: see below for full list of valid values
    sequence: <int>,              // Increments for each glucose value read
    timestamp: <int>,             // Glucose read time in seconds since transmitter start
    glucoseIsDisplayOnly: <bool>,
    glucose: <int>,               // Glucose value in mg/dL
    state: <int>,                 // Session Status: see below for full list of valid values
    trend: <int>                  // Glucose trend in mg/dL per 10 minutes
  },
  timeMessage: {
    status: <int>,                // Transmitter Status: see below for full list of valid values
    currentTime: <int>,           // Transmitter current time in seconds since transmitter start
    sessionStartTime: <int>       // Session start in seconds since transmitter start
  },
  status: <int>,                  // Transmitter Status: see below for full list of valid values
  state: <int>,                   // Session Status: see below for full list of valid values
  transmitterStartDate: <string>, // Time of transmitter start such as "2018-05-10T23:58:45.294Z"
  sessionStartDate: <string>,     // Time of session start such as "2018-08-23T16:09:34.294Z"
  readDate: <string>,             // Time of glucose value read such as "2018-08-26T18:58:19.294Z"
  isDisplayOnly: <bool>,
  filtered: <int>,                // Filtered glucose value in mg/dL * 1000
  unfiltered: <int>,              // Unfiltered glucose value in mg/dL * 1000
  glucose: <int>,                 // Current glucose value in mg/dL
  trend: <int>,                   // Glucose trend in mg/dL per 10 minutes
  canBeCalibrated: <bool>,        // Transmitter able to accept calibration command?
  rssi: <int>                     // Receive signal strength indicator
};

transmitter.on('glucose', callback(glucose));

Transmitter Status Valid Values

validTransmitterValues = [
  0x00, // OK
  0x81, // Low Battery
  0x83  // Expired
];

Session Status Valid Values

validSessionValues = [
  0x00, // None
  0x01, // Stopped
  0x02, // Warmup
  0x03, // Unused
  0x04, // First Calibration
  0x05, // Second Calibration
  0x06, // OK
  0x07, // Need calibration
  0x08, // Calibration Error 1
  0x09, // Calibration Error 0
  0x0a, // Calibration Linearity Fit Failure
  0x0b, // Sensor Failed Due to Counts Aberration
  0x0c, // Sensor Failed Due to Residual Aberration
  0x0d, // Out of Calibration Due To Outlier
  0x0e, // Outlier Calibration Request - Need a Calibration
  0x0f, // Session Expired
  0x10, // Session Failed Due To Unrecoverable Error
  0x11, // Session Failed Due To Transmitter Error
  0x12, // Temporary Session Failure - ???
  0x13, // Reserved
  0x80, // Calibration State - Start
  0x81, // Calibration State - Start Up
  0x82, // Calibration State - First of Two Calibrations Needed
  0x83, // Calibration State - High Wedge Display With First BG
  0x84, // Unused Calibration State - Low Wedge Display With First BG
  0x85, // Calibration State - Second of Two Calibrations Needed
  0x86, // Calibration State - In Calibration Transmitter
  0x87, // Calibration State - In Calibration Display
  0x88, // Calibration State - High Wedge Transmitter
  0x89, // Calibration State - Low Wedge Transmitter
  0x8a, // Calibration State - Linearity Fit Transmitter
  0x8b, // Calibration State - Out of Cal Due to Outlier Transmitter
  0x8c, // Calibration State - High Wedge Display
  0x8d, // Calibration State - Low Wedge Display
  0x8e, // Calibration State - Linearity Fit Display
  0x8f  // Calibration State - Session Not in Progress
];

Message processed

details = {
  time: <int> // epoch time
};

transmitter.on('messageProcessed', callback(details));

Battery Status

details = {
  voltagea: <int>,    // V * 200 - voltage level of battery a
  voltageb: <int>,    // V * 200 - voltage level of battery b
  resist: <int>,      // measured resistance - units unknown
  runtime: <int>,     // number of days since transmitter started
  temperature: <int>  // Centigrade temperature of transmitter
};

transmitter.on('batteryStatus', callback(details));

Transmitter Version Information

details = {
  status: <int>,                // Transmitter Status: see above for full list of valid values
  firmwareVersion: <string>,    // Semantic version of firmware
  btFirmwareVersion: <string>,  // Semantic version of bluetooth firmware
  asic: <int>,                  // Unknown
  buildVersion: <int>           // Build version
  inactiveDays: <int>           // Number of inactivate days of transmitter
  maxRuntimeDays: <int>         // Maximum number of days supported by transmitter
  maxInactiveDays: <int>        // Shelf life number of days supported by transmitter before opening
  typicalSensorDays: <int>      // How long does typical sensor session last
  featureBits: <int>            // Unknown
};

transmitter.on('version', callback(details));

Calibration data

calibrationData = {
  date: <string>, // time of last calibration such as "2018-08-26T18:58:19.294Z"
  glucose: <int>  // User entered calibration glucose in mg/dL
};

transmitter.on('calibrationData', callback(calibrationData));

Transmitter disconnected

transmitter.on('disconnect', callback());

Supported Messages

These messages can be sent to the transmitter by returning an array of them from the getMessagesCallback function

Sensor Start

startMsg = {
  type: 'StartSensor',
  date: <int>,            // epoch time to start sensor session
  sensorSerialCode: <int> // sensor serial number
};

Sensor Stop

stopMsg = {
  type: 'StopSensor',
  date: <int>         // epoch time to stop sensor session
};

Calibrate Sensor

calibrateMsg = {
  type: 'CalibrateSensor',
  date: <int>,            // epoch time of glucose reading
  glucose: <int>          // glucose value in mg/dL
};

Reset Transmitter

resetMsg = {
  type: 'ResetTx'
};

Request Battery Status

batteryStatusRequestMsg = {
  type: 'BatteryStatus'
};

Request Transmitter Version Information

VersionRequestMsg = {
  type: 'VersionRequest'
};