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add payload decoder function for TTN Stack V3
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@thiasB
thiasB committed Mar 2, 2021
1 parent 82a0541 commit 71699de
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0 client/TTN/decoder.js → client/TTN/decoder_v2.js
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166 changes: 166 additions & 0 deletions client/TTN/decoder_v3.js
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/**
* @reference https://github.com/myDevicesIoT/cayenne-docs/blob/master/docs/LORA.md
* @reference http://openmobilealliance.org/wp/OMNA/LwM2M/LwM2MRegistry.html#extlabel
*
* Adapted for lora-app-server from https://gist.github.com/iPAS/e24970a91463a4a8177f9806d1ef14b8
*
* Type IPSO LPP Hex Data Size Data Resolution per bit
* Digital Input 3200 0 0 1 1
* Digital Output 3201 1 1 1 1
* Analog Input 3202 2 2 2 0.01 Signed
* Analog Output 3203 3 3 2 0.01 Signed
* Illuminance Sensor 3301 101 65 2 1 Lux Unsigned MSB
* Presence Sensor 3302 102 66 1 1
* Temperature Sensor 3303 103 67 2 0.1 °C Signed MSB
* Humidity Sensor 3304 104 68 1 0.5 % Unsigned
* Accelerometer 3313 113 71 6 0.001 G Signed MSB per axis
* Barometer 3315 115 73 2 0.1 hPa Unsigned MSB
* Time 3333 133 85 4 Unix time MSB
* Gyrometer 3334 134 86 6 0.01 °/s Signed MSB per axis
* GPS Location 3336 136 88 9 Latitude : 0.0001 ° Signed MSB
* Longitude : 0.0001 ° Signed MSB
* Altitude : 0.01 meter Signed MSB
*
* Additional types
* Generic Sensor 3300 100 64 4 Unsigned integer MSB
* Voltage 3316 116 74 2 0.01 V Unsigned MSB
* Current 3317 117 75 2 0.001 A Unsigned MSB
* Frequency 3318 118 76 4 1 Hz Unsigned MSB
* Percentage 3320 120 78 1 1% Unsigned
* Altitude 3321 121 79 2 1m Signed MSB
* Load 3322 122 7A 3 0.001 Signed MSB
* Power 3328 128 80 2 1 W Unsigned MSB
* Distance 3330 130 82 4 0.001m Unsigned MSB
* Energy 3331 131 83 4 0.001kWh Unsigned MSB
* Direction 3332 132 84 2 1º Unsigned MSB
* Switch 3342 142 8E 1 0/1
*
*/

// lppDecode decodes an array of bytes into an array of ojects,
// each one with the channel, the data type and the value.
function lppDecode(bytes) {

var sensor_types = {
0 : {'size': 1, 'name': 'digital_in', 'signed': false, 'divisor': 1},
1 : {'size': 1, 'name': 'digital_out', 'signed': false, 'divisor': 1},
2 : {'size': 2, 'name': 'analog_in', 'signed': true , 'divisor': 100},
3 : {'size': 2, 'name': 'analog_out', 'signed': true , 'divisor': 100},
100: {'size': 4, 'name': 'generic', 'signed': false, 'divisor': 1},
101: {'size': 2, 'name': 'illuminance', 'signed': false, 'divisor': 1},
102: {'size': 1, 'name': 'presence', 'signed': false, 'divisor': 1},
103: {'size': 2, 'name': 'temperature', 'signed': true , 'divisor': 10},
104: {'size': 1, 'name': 'relative_humidity', 'signed': false, 'divisor': 2},
113: {'size': 6, 'name': 'accelerometer', 'signed': true , 'divisor': 1000},
115: {'size': 2, 'name': 'barometric_pressure', 'signed': false, 'divisor': 10},
116: {'size': 2, 'name': 'voltage', 'signed': false, 'divisor': 100},
117: {'size': 2, 'name': 'current', 'signed': false, 'divisor': 1000},
118: {'size': 4, 'name': 'frequency', 'signed': false, 'divisor': 1},
120: {'size': 1, 'name': 'percentage', 'signed': false, 'divisor': 1},
121: {'size': 2, 'name': 'altitude', 'signed': true, 'divisor': 1},
122: {'size': 3, 'name': 'load', 'signed': true, 'divisor': 1000},
128: {'size': 2, 'name': 'power', 'signed': false, 'divisor': 1},
130: {'size': 4, 'name': 'distance', 'signed': false, 'divisor': 1000},
131: {'size': 4, 'name': 'energy', 'signed': false, 'divisor': 1000},
132: {'size': 2, 'name': 'direction', 'signed': false, 'divisor': 1},
133: {'size': 4, 'name': 'time', 'signed': false, 'divisor': 1},
134: {'size': 6, 'name': 'gyrometer', 'signed': true , 'divisor': 100},
136: {'size': 9, 'name': 'gps', 'signed': true, 'divisor': [10000,10000,100]},
142: {'size': 1, 'name': 'switch', 'signed': false, 'divisor': 1},
};

function arrayToDecimal(stream, is_signed, divisor) {

var value = 0;
for (var i = 0; i < stream.length; i++) {
if (stream[i] > 0xFF)
throw 'Byte value overflow!';
value = (value << 8) | stream[i];
}

if (is_signed) {
var edge = 1 << (stream.length) * 8; // 0x1000..
var max = (edge - 1) >> 1; // 0x0FFF.. >> 1
value = (value > max) ? value - edge : value;
}

value /= divisor;

return value;

}

var sensors = [];
var i = 0;
while (i < bytes.length) {

var s_no = bytes[i++];
var s_type = bytes[i++];
if (typeof sensor_types[s_type] == 'undefined') {
throw 'Sensor type error!: ' + s_type;
}

var s_value = 0;
var type = sensor_types[s_type];
switch (s_type) {

case 113: // Accelerometer
case 134: // Gyrometer
s_value = {
'x': arrayToDecimal(bytes.slice(i+0, i+2), type.signed, type.divisor),
'y': arrayToDecimal(bytes.slice(i+2, i+4), type.signed, type.divisor),
'z': arrayToDecimal(bytes.slice(i+4, i+6), type.signed, type.divisor)
};
break;

case 136: // GPS Location
s_value = {
'latitude': arrayToDecimal(bytes.slice(i+0, i+3), type.signed, type.divisor[0]),
'longitude': arrayToDecimal(bytes.slice(i+3, i+6), type.signed, type.divisor[1]),
'altitude': arrayToDecimal(bytes.slice(i+6, i+9), type.signed, type.divisor[2])
};
break;

default: // All the rest
s_value = arrayToDecimal(bytes.slice(i, i + type.size), type.signed, type.divisor);
break;
}

sensors.push({
'channel': s_no,
'type': s_type,
'name': type.name,
'value': s_value
});

i += type.size;

}

return sensors;

}

// To use with TTN
function decodeUplink(input) {

// flat output (like original decoder):
var response = {};
lppDecode(input.bytes, 1).forEach(function(field) {
response[field['name'] + '_' + field['channel']] = field['value'];
});
return {
data: response
};

// field output
//return {'fields': lppDecode(bytes, fPort)};

}

// To use with NodeRED
// Assuming msg.payload contains the LPP-encoded byte array
/*
msg.fields = lppDecode(msg.payload);
return msg;
*/

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