BROWAN - Object Locator

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/* eslint-disable no-bitwise */ /* eslint-disable no-restricted-properties */ function Decoder(bytes, port) { const decoded = []; if (port === 136) { // STATUS decoded.push({ variable: "button_trigger_event", value: bytes[0] & 1 }); decoded.push({ variable: "no_gnss_fix", value: (bytes[0] & 0x0f) >> 3 }); // BATTERY const battery_level = bytes.readUInt8(1); decoded.push({ variable: "battery", value: (25 + (battery_level & 0x0f)) / 10, unit: "V" }); decoded.push({ variable: "remaining_battery_capacity", value: Number((100 * ((battery_level >> 4) / 15)).toPrecision(4)), unit: "%" }); // TEMPERATURE decoded.push({ variable: "temperature", value: (bytes.readUInt8(2) & 0x7f) - 32, unit: "°C" }); // LOCATION // GNSS Fix? let positionGnssFix = false; if ((bytes[0] & 0x8) === 0) { positionGnssFix = true; } // Accuracy Measurement let positionAccuracy = bytes[10] >> 5; positionAccuracy = Math.pow(2, parseInt(positionAccuracy) + 2); // Mask off end of accuracy byte, so longitude doesn't get affected bytes[10] &= 0x1f; if ((bytes[10] & (1 << 4)) !== 0) { bytes[10] |= 0xe0; } // Mask off end of latitude byte, RFU bytes[6] &= 0x0f; // Latitude and Longitude Measurement let positionLatitude = (bytes[6] << 24) | (bytes[5] << 16) | (bytes[4] << 8) | bytes[3]; let positionLongitude = (bytes[10] << 24) | (bytes[9] << 16) | (bytes[8] << 8) | bytes[7]; positionLatitude /= 1000000; positionLongitude /= 1000000; decoded.push({ variable: "location", value: `${positionLatitude},${positionLongitude}`, location: { lat: positionLatitude, lng: positionLongitude } }); decoded.push({ variable: "accuracy", value: positionAccuracy, unit: "m" }); } return decoded; } const data = payload.find((x) => x.variable === "payload" || x.variable === "payload_raw" || x.variable === "data"); const port = payload.find((x) => x.variable === "port" || x.variable === "fport"); if (data && port) { const serie = data.serie || new Date().getTime(); const bytes = Buffer.from(data.value, "hex"); payload = payload.concat(Decoder(bytes, Number(port.value))).map((x) => ({ ...x, serie })); }