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liamcottleliamcottle
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add cayenne lpp parser
1 parent 1b5c11f commit 3fcd1ec

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‎src/buffer_reader.js‎

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@@ -60,24 +60,59 @@ class BufferReader {
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return view.getUint16(0, true);
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}
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readUInt16BE() {
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const bytes = this.readBytes(2);
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const view = new DataView(bytes.buffer);
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return view.getUint16(0, false);
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}
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readUInt32LE() {
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const bytes = this.readBytes(4);
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const view = new DataView(bytes.buffer);
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return view.getUint32(0, true);
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}
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readUInt32BE() {
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const bytes = this.readBytes(4);
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const view = new DataView(bytes.buffer);
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return view.getUint32(0, false);
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}
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readInt16LE() {
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const bytes = this.readBytes(2);
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const view = new DataView(bytes.buffer);
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return view.getInt16(0, true);
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}
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readInt16BE() {
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const bytes = this.readBytes(2);
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const view = new DataView(bytes.buffer);
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return view.getInt16(0, false);
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}
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readInt32LE() {
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const bytes = this.readBytes(4);
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const view = new DataView(bytes.buffer);
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return view.getInt32(0, true);
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}
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readInt24BE() {
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// read 24-bit (3 bytes) big endian integer
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var value = (this.readByte() << 16) | (this.readByte() << 8) | this.readByte();
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// convert 24-bit signed integer to 32-bit signed integer
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// 0x800000 is the sign bit for a 24-bit value
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// if it's set, value is negative in 24-bit two's complement
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// so we subtract 0x1000000 (which is 2^24) to get the correct negative value as a Dart integer
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if((value & 0x800000) !== 0){
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value -= 0x1000000;
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}
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return value;
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}
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}
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export default BufferReader;

‎src/cayenne_lpp.js‎

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import BufferReader from "./buffer_reader.js";
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class CayenneLpp {
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static LPP_DIGITAL_INPUT = 0; // 1 byte
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static LPP_DIGITAL_OUTPUT = 1; // 1 byte
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static LPP_ANALOG_INPUT = 2; // 2 bytes, 0.01 signed
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static LPP_ANALOG_OUTPUT = 3; // 2 bytes, 0.01 signed
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static LPP_GENERIC_SENSOR = 100; // 4 bytes, unsigned
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static LPP_LUMINOSITY = 101; // 2 bytes, 1 lux unsigned
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static LPP_PRESENCE = 102; // 1 byte, bool
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static LPP_TEMPERATURE = 103; // 2 bytes, 0.1°C signed
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static LPP_RELATIVE_HUMIDITY = 104; // 1 byte, 0.5% unsigned
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static LPP_ACCELEROMETER = 113; // 2 bytes per axis, 0.001G
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static LPP_BAROMETRIC_PRESSURE = 115; // 2 bytes 0.1hPa unsigned
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static LPP_VOLTAGE = 116; // 2 bytes 0.01V unsigned
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static LPP_CURRENT = 117; // 2 bytes 0.001A unsigned
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static LPP_FREQUENCY = 118; // 4 bytes 1Hz unsigned
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static LPP_PERCENTAGE = 120; // 1 byte 1-100% unsigned
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static LPP_ALTITUDE = 121; // 2 byte 1m signed
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static LPP_CONCENTRATION = 125; // 2 bytes, 1 ppm unsigned
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static LPP_POWER = 128; // 2 byte, 1W, unsigned
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static LPP_DISTANCE = 130; // 4 byte, 0.001m, unsigned
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static LPP_ENERGY = 131; // 4 byte, 0.001kWh, unsigned
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static LPP_DIRECTION = 132; // 2 bytes, 1deg, unsigned
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static LPP_UNIXTIME = 133; // 4 bytes, unsigned
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static LPP_GYROMETER = 134; // 2 bytes per axis, 0.01 °/s
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static LPP_COLOUR = 135; // 1 byte per RGB Color
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static LPP_GPS = 136; // 3 byte lon/lat 0.0001 °, 3 bytes alt 0.01 meter
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static LPP_SWITCH = 142; // 1 byte, 0/1
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static LPP_POLYLINE = 240; // 1 byte size, 1 byte delta factor, 3 byte lon/lat 0.0001° * factor, n (size-8) bytes deltas
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static parse(bytes) {
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const buffer = new BufferReader(bytes);
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const telemetry = [];
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while(buffer.getRemainingBytesCount() >= 2){ // need at least 2 more bytes to get channel and type
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const channel = buffer.readUInt8();
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const type = buffer.readUInt8();
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// stop parsing if channel and type are zero, as there seems to be garbage bytes???
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if(channel === 0 && type === 0){
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break;
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}
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switch(type){
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case this.LPP_GENERIC_SENSOR: {
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const value = buffer.readUInt32BE();
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// console.log(`[CayenneLpp] parsed LPP_GENERIC_SENSOR=${value}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": value,
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});
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break;
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}
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case this.LPP_LUMINOSITY: {
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const lux = buffer.readInt16BE();
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// console.log(`[CayenneLpp] parsed LPP_LUMINOSITY=${lux}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": lux,
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});
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break;
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}
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case this.LPP_PRESENCE: {
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const presence = buffer.readUInt8();
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// console.log(`[CayenneLpp] parsed LPP_PRESENCE=${presence}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": presence,
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});
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break;
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}
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case this.LPP_TEMPERATURE: {
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const temperature = buffer.readInt16BE() / 10;
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// console.log(`[CayenneLpp] parsed LPP_TEMPERATURE=${temperature}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": temperature,
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});
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break;
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}
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case this.LPP_RELATIVE_HUMIDITY: {
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const relativeHumidity = buffer.readUInt8() / 2;
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// console.log(`[CayenneLpp] parsed LPP_RELATIVE_HUMIDITY=${relativeHumidity}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": relativeHumidity,
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});
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break;
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}
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case this.LPP_BAROMETRIC_PRESSURE: {
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const barometricPressure = buffer.readUInt16BE() / 10;
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// console.log(`[CayenneLpp] parsed LPP_BAROMETRIC_PRESSURE=${barometricPressure}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": barometricPressure,
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});
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break;
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}
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case this.LPP_VOLTAGE: {
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// uint16: 0v to 655.35v
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// int16: -327.67v to +327.67v
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// should be readUInt16BE, but I'm using readInt16BE to allow for negative voltage
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const voltage = buffer.readInt16BE() / 100;
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// console.log(`[CayenneLpp] parsed LPP_VOLTAGE=${voltage}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": voltage,
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});
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break;
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}
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case this.LPP_CURRENT: {
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// uint16: 0A to 655.35A
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// int16: -327.67A to +327.67A
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// should be readUInt16BE, but I'm using readInt16BE to allow for negative current
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const current = buffer.readInt16BE() / 1000;
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// console.log(`[CayenneLpp] parsed LPP_CURRENT=${current}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": current,
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});
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break;
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}
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case this.LPP_PERCENTAGE: {
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const percentage = buffer.readUInt8();
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// console.log(`[CayenneLpp] parsed LPP_PERCENTAGE=${percentage}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": percentage,
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});
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break;
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}
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case this.LPP_CONCENTRATION: {
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const concentration = buffer.readUInt16BE();
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// console.log(`[CayenneLpp] parsed LPP_CONCENTRATION=${concentration}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": concentration,
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});
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break;
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}
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case this.LPP_POWER: {
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const power = buffer.readUInt16BE();
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// console.log(`[CayenneLpp] parsed LPP_POWER=${power}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": power,
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});
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break;
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}
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case this.LPP_GPS: {
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const latitude = buffer.readInt24BE() / 10000;
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const longitude = buffer.readInt24BE() / 10000;
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const altitude = buffer.readInt24BE() / 100;
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// console.log(`[CayenneLpp] parsed LPP_GPS=${latitude},${longitude},${altitude}`);
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telemetry.push({
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"channel": channel,
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"type": type,
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"value": {
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latitude: latitude,
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longitude: longitude,
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altitude: altitude,
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},
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});
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break;
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}
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// todo support all telemetry types, otherwise if an unknown is given, we can't read other telemetry after it
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default: {
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// console.log(`[CayenneLpp] unsupported type: ${type}`);
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return telemetry;
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}
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}
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}
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return telemetry;
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}
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}
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export default CayenneLpp;

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