Temperature Sensor - BME280

Temperature / Humidity / Air pressure sensor.
Very low energy consumption and high accuracy.

wired(obniz, {[vio, vcore, gnd, csb, sdi, sck, sdo, address, i2c]} )

Connect a sensor to an obniz Board.
obniz Board has internal pull up. But for communication stability, please add pull-up resistor to both SCK and SDI.

Not recommended direct connecting.

This library use I2C to communicate.

// Javascript Example
// Please pullup sdi and sck.
var bme280 = obniz.wired("BME280", {vio:0, vcore:1, gnd:2, csb:3, sdi: 4, sck: 5, sdo:6 });
await bme280.applyCalibrationWait();
const val = await bme280.getAllWait();
console.log(val);

vio and vcore can be connected.
csb can be connected to high simply, and sdo can be connected to low.
So, minimum connection and configration is.

// Javascript Example

// vcore connected to vio
// csb connected to vio
// sdo connected to gnd

var bme280 = obniz.wired("BME280", {vio:0, gnd:1, sdi: 2, sck: 3 });
await bme280.applyCalibrationWait();
const val = await bme280.getAllWait();
console.log(val);

Or you can use i2c object

// Javascript Example

var i2c = obniz.getFreeI2C();
i2c.start({mode:"master", sda:2, scl:3, clock:100000}); 

var bme280 = obniz.wired("BME280", {vio:0, gnd:1, i2c: i2c });

If you configured a chip to use address 0x77 (by pull-up sdo)

// Javascript Example

var bme280 = obniz.wired("BME280", {vio:0, gnd:1, sdi: 2, sck: 3, address: 0x77});

[await] applyCalibrationWait()

Retrive factory stored calibration data from connected chip.
You can use BME280 without calling this, But You should do for better accuracy.

// Javascript Example
// Please pullup sdi and sck.
var bme280 = obniz.wired("BME280", {vio:0, vcore:1, gnd:2, csb:3, sdi: 4, sck: 5, sdo:6 });
await bme280.applyCalibrationWait();

[await] setIIRStrengthWait()

configure of internal IIR filter. 0 to 4.

0 for disable IIR filter.(default)

IIR filter makes more stable and accurate result.
But you should wait for get more accurate result.

// Javascript Example
// Please pullup sdi and sck.
var bme280 = obniz.wired("BME280", {vio:0, vcore:1, gnd:2, csb:3, sdi: 4, sck: 5, sdo:6 });
await bme280.applyCalibrationWait();
await bme280.setIIRStrength(1); // start using minimum IIR 

[await] getAllWait()

get all values.

• temperature: celcius
• humidity: %
• pressure: hPa

// Javascript Example
// Please pullup sdi and sck.
var bme280 = obniz.wired("BME280", {vio:0, vcore:1, gnd:2, csb:3, sdi: 4, sck: 5, sdo:6 });
await bme280.applyCalibrationWait();
const obj = await bme280.getAllWait();
console.log('temp: ' + obj.temperature + ' degree');
console.log('humidity: ' + obj.humidity + ' %');
console.log('pressure: ' + obj.pressure + ' hPa');

calcAltitude(pressure, seaPressure)

Utility function for calcurate accuracy using air pressure.
Unit is m.

// Javascript Example
// Please pullup sdi and sck.
var bme280 = obniz.wired("BME280", {vio:0, vcore:1, gnd:2, csb:3, sdi: 4, sck: 5, sdo:6 });
await bme280.applyCalibrationWait();
const obj = await bme280.getAllWait();
const airPressure = obj.pressure;
const hight_in_m = bme280.calcAltitude(airPressure);
console.log('altitude: ' + hight_in_m + ' m');