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parasquid/airquality.js

Created November 12, 2020 13:22
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airquality.js
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airquality.js
const getUuid = (i) => {
const num = i.toString();
const id = ("0").repeat((4 - num.length) > 0 ? (4 - num.length) : 0) + num;
return 'd7e5' + id + '-0109-4306-956f-2f725ba7a85d';
};
var s = new Serial();
s.setup(9600,{rx: D33, tx: D34});
let buffer = '';
const header = String.fromCharCode(0x42) + String.fromCharCode(0x4d);
let pmData = {};
const calculateChecksum = (arr) => {
return arr.reduce((acc, cur) => (acc + cur), 0) - arr[30] - arr[31];
};
s.on('data', function (data) {
buffer = buffer + data;
if(buffer.length < 32) {
// get at least 32 bytes
} else {
// find header and discard any previous bytes in buffer
const index = buffer.indexOf(header);
if(index != -1) { // found the header
buffer = buffer.substr(index); // discard previous bytes until header
if(buffer.length >= 32) {
buffer = buffer.substr(0, 32); // get a complete packet
const arrayBuffer = E.toArrayBuffer(buffer);
buffer = buffer.substr(32); // set buffer to leftover bytes
const dataView = new DataView(arrayBuffer);
data = {
header: dataView.getUint16(0),
length: dataView.getUint16(2),
pm25: dataView.getUint8(6 + 1),
pm10: dataView.getUint8(8 + 1),
checksum: dataView.getUint16(30),
};
const calculatedChecksum = calculateChecksum(new Uint8Array(arrayBuffer));
// early return on bad data
if (data.length != 28) {
// print(data.length);
return;
}
if (calculatedChecksum != data.checksum) {
print(calculatedChecksum, data.checksum, calculatedChecksum - data.checksum, arrayBuffer);
// we're getting too many invalid checksums so comment out
// the early return for now ...
//return;
}
pmData = {pm25: data.pm25, pm10: data.pm10, t: Date.now()};
digitalPulse(LED1, true, 50);
}
} else { // header not found
}
}
});
const SDA = 30;
const SCL = 31;
I2C1.setup({scl:SCL,sda:SDA});
var exports={};
var C = {
I2C_ADDRESS : 0x40,
};
function HDC1080(i2c, deviceAddress) {
this.i2c = i2c;
this.deviceAddress = deviceAddress;
}
HDC1080.prototype.read = function() {
this.i2c.writeTo(this.deviceAddress, 0);
return new Promise((resolve, reject) => {
setTimeout(() => {
const data = this.i2c.readFrom(this.deviceAddress, 4);
const temp = data[1] | data[0] << 8;
const hum = data[3] | data[2] << 8;
resolve({
temperature: (temp / 65536) * 165.0 - 40.0,
humidity: (hum / 65536) * 100.0,
});
}, 25);
});
};
exports.connect = function (i2c, deviceAddress) {
return new HDC1080(i2c, deviceAddress || C.I2C_ADDRESS);
};
var gas = require("CCS811").connectI2C(I2C1, {int : 29});
var hdc = exports.connect(I2C1);
var temperature = 25;
var humidity = 50;
const start = () => {
g.clear();
g.setFont("6x8");
g.drawString("Hello World!",0,0);
g.flip();
};
var g = require("SSD1306").connect(I2C1, start);
require("Font6x8").add(Graphics);
const bleService = (value, description) => {
return {
value: [value],
readable: true,
maxLen: 8,
notify : true,
description: description,
};
};
const defaultServices = {
0x181A: { // org.bluetooth.descriptor.es_measurement
0x2A6E: bleService(temperature),
0x2A6F: bleService(humidity),
}
};
defaultServices[0x181A][getUuid(1)] = bleService(400, 'eCO2');
defaultServices[0x181A][getUuid(2)] = bleService(0, 'TVOC');
defaultServices[0x181A][getUuid(3)] = bleService(0, 'pm 2.5');
defaultServices[0x181A][getUuid(4)] = bleService(0, 'pm 10');
defaultServices[0x181A][getUuid(5)] = bleService(0, 'beat');
NRF.setServices(defaultServices, { advertise: [ '0x181A' ] });
const littleEndian = (value) => {
return [value&255, value>>8];
};
gas.on('data', (data) => {
hdc.read().then((e) => {
temperature = e.temperature;
humidity = e.humidity;
});
gas.setEnvData(humidity, temperature);
print(data, temperature, humidity, pmData);
g.clear();
g.setFont("6x8");
g.drawString('eCO2 : ' + data.eCO2, 0, 0);
g.drawString('TVOC : ' + data.TVOC, 0, 10);
g.drawString('temp : ' + temperature, 0, 20);
g.drawString('hmdty: ' + humidity, 0, 30);
g.drawString('pm2.5: ' + pmData.pm25, 0, 40);
g.drawString('pm10 : ' + pmData.pm10, 0, 50);
g.flip();
// Bluetooth spec says data is 16 bits, 0.01/unit - so x100
const t = Math.round(temperature*100);
const h = Math.round(humidity*100);
const advertData = {
0x2A6E: littleEndian(t),
0x2A6F: littleEndian(h),
};
NRF.setAdvertising(advertData);
const serviceData = {
0x181A: { // org.bluetooth.descriptor.es_measurement
0x2A6E: { // temperature
value: littleEndian(t),
notify: true,
},
0x2A6F: { // humidity
value: littleEndian(h),
notify: true,
},
}
};
serviceData[0x181A][getUuid(1)] = { value: littleEndian(data.eCO2), notify: true };
serviceData[0x181A][getUuid(2)] = { value: littleEndian(data.TVOC), notify: true };
serviceData[0x181A][getUuid(3)] = { value: littleEndian(pmData.pm25), notify: true };
serviceData[0x181A][getUuid(4)] = { value: littleEndian(pmData.pm10), notify: true };
serviceData[0x181A][getUuid(5)] = { value: [pmData.t], notify: true };
NRF.updateServices(serviceData, { advertise: [ '0x181A' ] });
});
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