MCP9808 I2C temperature sensor module for Node.js on Linux boards like the Raspberry Pi or BeagleBone.
Supports Node.js versions 6, 8, 10, 12 and 13.
- Simple temperature sensing
- Alert detection
- Real hardware interrupts used to detect alerts, no polling needed
- Promise based asynchronous API
npm install mcp9808-temperature-sensor
Note that neither the 10kΩ pull-up resistor nor the wire connecting Alert on the MCP9808 breakout board to GPIO27 on the Raspberry Pi are needed for the "Report the Temperature" example. They are needed for the "Alerts" example.
Log the temperature in degrees Celsius to the console.
const mcp9808 = require('mcp9808-temperature-sensor');
mcp9808.open().then(sensor =>
sensor.temperature().
then(temp => console.log(temp.celsius + '°C')).
then(_ => sensor.close())
).catch(console.log);Fire alert events if the temperature drops below 25°C, goes above 35°C or becomes critical at 45°C.
A hair dryer or blow dryer can be used to blow hot air over the MCP9808 temperature sensor and increase its temperature.
const mcp9808 = require('mcp9808-temperature-sensor');
mcp9808.open({
i2cBusNumber: 1, // optional, default 1
i2cAddress: 0x18, // optional, default 0x18
alertGpioNumber: 27,
lowerAlertTemperature: 25,
upperAlertTemperature: 35,
criticalTemperature: 45
}).then(sensor => {
setInterval(_ => {
sensor.temperature().then(temp => console.log(temp.celsius + '°C'));
}, 1000);
sensor.on('alert', temp => {
console.log(' alert ' + temp.celsius + '°C');
if (temp.critical) {
console.log(' critical');
}
if (temp.aboveUpperLimit) {
console.log(' above upper limit');
}
if (temp.belowLowerLimit) {
console.log(' below lower limit');
}
});
return sensor.enableAlerts();
}).catch(console.log);- RESOLUTION_1_2
- RESOLUTION_1_4
- RESOLUTION_1_8
- RESOLUTION_1_16
- HYSTERESIS_0
- HYSTERESIS_1_5
- HYSTERESIS_3
- HYSTERESIS_6
Returns a promise for an Mcp9808 object.
The following options are supported:
- i2cBusNumber - integer, I2C bus number, optional, default 1
- i2cAddress - integer, MCP9808 I2C address, optional, default 0x18
- alertGpioNumber - integer, GPIO number of the GPIO used for alert interrupt detection, see onoff, optional, no default, none used if none specified
- lowerAlertTemperature - number, alert lower temperature boundary, optional, default 0°C
- upperAlertTemperature - number, alert upper temperature boundary, optional, default 0°C
- criticalTemperature - number, alert critical temperature boundary, optional, default 0°C
- resolution - integer, sensor resolution, see resolution constants, optional, default 0.0625°C
- hysteresis - hysteresis for lower, upper and critical temperatures, see hysteresis constants, optional, default 0°C
Returns a promise which will resolve when all resources used by the Mcp9808 object have been freed.
Returns a promise for an object containing temperature data.
Returns a promise which will resolve when alerts have been enabled for the Mcp9808.
- temperatureData - object containing temperature data
Fired when an alert is detected.
- err - Error object
Fired when an error occurs during alert detection.
0.5°C resolution.
0.25°C resolution.
0.125°C resolution.
0.0625°C resolution.
0°C hysteresis.
1.5°C hysteresis.
3°C hysteresis.
6°C hysteresis.
- celsius - number, temperature in degrees Celsius
- belowLowerLimit - boolean, true if temperature less than lower limit, else false
- aboveUpperLimit - boolean, true if temperature greater than upper limit, else false
- critical - boolean, true if temperature greater than or equal to critical temperature, else false