/**
* Parser for Lobaro Pressure Probe via LoRaWAN (hybrid gateway).
* Usable for Pressure Probe as or with Presure+Temperature Probe.
* Works with TTN, ChirpStack, or the Lobaro Platform.
*/
function signed(val, bits) {
// max positive value possible for signed int with bits:
var mx = Math.pow(2, bits-1);
if (val < mx) {
// is positive value, just return
return val;
} else {
// is negative value, convert to neg:
return val - (2 * mx);
}
}
function int16_BE(bytes, idx) {
bytes = bytes.slice(idx || 0);
return signed(bytes[0] << 8 | bytes[1] << 0, 2*8);
}
function uint16_BE(bytes, idx) {
bytes = bytes.slice(idx || 0);
return bytes[0] << 8 | bytes[1] << 0;
}
function uint32_BE(bytes, idx) {
bytes = bytes.slice(idx || 0);
return bytes[0] << 24 | bytes[1] << 16 | bytes[2] << 8 | bytes[3] << 0;
}
function float32FromInt(asInt) {
var sign = (asInt & 0x80000000) ? -1 : 1;
var exponent = ((asInt >> 23) & 0xFF) - 127;
var significand = (asInt & ~(-1 << 23));
if (exponent === 128)
return null;
// return sign * ((significand) ? Number.NaN : Number.POSITIVE_INFINITY);
if (exponent === -127) {
if (significand === 0) return sign * 0.0;
exponent = -126;
significand /= (1 << 22);
} else significand = (significand | (1 << 23)) / (1 << 23);
return sign * significand * Math.pow(2, exponent);
}
function float32_BE(bytes, idx) { return float32FromInt(uint32_BE(bytes, idx)); }
/**
* TTN decoder function.
*/
function Decoder(bytes, port) {
var vals = {};
if( port == 20 ){
if (bytes.length==75) {
// Pressure Probe without temperature sensor
// make sure that unit is mH2O and precisionBridges isinternal 3 decimals
if( (uint16_BE(bytes, 1)==7) && (uint16_BE(bytes, 3)==3)){
Temperature
vals["error"] = !!(bytes[0]&0x80);
vals["pressure"] = int16_BE(bytes, 51)/1000;
}
else{
vals["error vals["temperature"] = true;
vals["pressure"] = null;
}int16_BE(bytes, 3);
} else if (bytes.length==9) {
vals["error"] = !!(bytes[0]&0x80);
// pressure in mH2O
vals["pressure"] = float32_BE(bytes, 1);
// temperature in Degree Celsius
vals["temperature"] = float32_BE(bytes, 5);
}
}
return vals;
}
/**
* TTN V3 Wrapper
*/
function decodeUplink(input) {
return {
data: {
values: Decoder(input.bytes, input.fPort)
},
warnings: [],
errors: []
};
}
/**
* ChirpStack decoder function.
*/
function Decode(fPort, bytes) {
// wrap TTN Decoder:
return Decoder(bytes, fPort);
}
/**
* Lobaro Platform decoder function.
*/
function Parse(input) {
var data = bytes(atob(input.data));
var port = input.fPort;
return Decoder(data, port);
} |