[Archive] HTS221 Temperature and Humidity Sensor
This library has been archived and is no longer supported. The latest version of the HTS221 Temperature and Humidity Sensor Library can be found here.
The HTS221 is an accurate and versatile sensor used for detecting the ambient temperature and humidity of an area. The HTS221 sensor supports communication via the I2C communication protocol.
The HTS221 is very simple to operate in both hardware and software.
For information on how to import neqto.js libraries, please refer to this documentation.
Setup
Hardware
The NEQTO HTS221 module has 5 pins on its bottom for connecting to the I2CM port at the bottom of the NEQTO Bridge. The HTS221 module lines up its pins from right to left, and should fit snugly into the module port. When aligned correctly, the two screw-holes at the bottom of the module should be exposed for more permanent attachment.
For other devices, the NEQTO HTS221 module can connect with any I2C port by means of a sensor connector.
Software
To interface with an HTS221 sensor, it is required to create a sensor object and then call the init function to initialize the sensor. Once the sensor object is created and initialized, it is possible to read the sensor data using the getResult function.
Usage
Creation
All NEQTO I2C libraries follow the same format for creation. The HTS221 takes the following parameter at creation:
i2c: the I2C instance representing the I2C node on the board that this sensor connects to. In this case, users should pass an I2C instance made from node 1.
init
The HTS221 needs to be initialized before it can read data from its surroundings. Calling on the HTS221 sensor object will ready it to take readings. This only needs to happen once.
Returns: {boolean}
If it is unable to initialize, the init() function returns false. Otherwise, it does not return.
getResult
Returns: {object}
A JavaScript object containing the sensor data, in the following format:
{
temp: temperature (Number), // UNIT: Celsius (C), -40 to +120, RESO: 0.1
humi: humidity (Number) // UNIT: Percent (%), 0 to 100, RESO: 0.1
}
Example Script
The following script is an example of a user script after importing the HTS221 sensor library.
The user will turn on interfaces on the NEQTO Bridge, and create a new I2C device object to interface with the HTS221 sensor.
The user wants to measure 10 readings from the HTS221 at a rate of one reading per second, and output the average to the serial console.
// IMPORTED LIBRARIES
// - HTS221
// Logging setup
log.setLevel(2); //-1:NONE 0:ERROR 1:WARNING 2:DEBUG 3:TRACE
log.printLevel(2); //0:DISABLE 1:LOG 2:CONSOLE 3:BOTH
log.clear();
//Use standard interface of NEQTO IO board
nqEx.enI2CS(true);
nqEx.enI2CL(true);
//I2C Config
var baudrate = 400000;
var i2c = new I2C(1);
i2c.open(baudrate);
var hts = new HTS221(i2c);
var ready = hts.init();
var iteration = 1;
var sums = [0, 0];
var MAX_NUM_ITERATIONS = 10;
var ITERATION_INTERVAL = 1000; // in milliseconds
if (!ready) {
print("UNABLE TO CONNECT TO HTS221");
print("EXITING...");
} else {
var loop = setInterval(function () {
var results = hts.getResult();
sums[0] += results.temp;
sums[1] += results.humi;
if (iteration++ == MAX_NUM_ITERATIONS) {
print("PRINTING AVERAGE TEMPERATURES...");
print((sums[0] / 10).toFixed(2));
print("PRINTING AVERAGE HUMIDITIES...");
print((sums[1] / 10).toFixed(2));
sums = [0, 0];
iteration = 1;
}
}, ITERATION_INTERVAL)
}