SHT15 digital humidity sensor and MBed example
In this example we will connect a SHT15 sensor to an MBED 1768, in this example we will be using the MBed online compiler
The SHT1x digital humidity sensor is a reflow solderable sensor. The SHT1x series consists of a low-cost version with the SHT10 humidity sensor, a standard version with the SHT11 humidity sensor, and a high-end version with the SHT15 humidity sensor. As with every other Sensirion sensor type from the SHTxx humidity sensor family, they are fully calibrated and provide a digital output.
The SHT1x humidity sensor series (including SHT10, SHT11, and SHT15) is Sensirion’s family of surface-mountable relative humidity sensors. The humidity sensors integrate sensor elements plus signal processing on a tiny footprint and provide a fully calibrated digital output. A unique capacitive sensor element is used for measuring relative humidity, while temperature is measured by a band-gap sensor. Its CMOSens® technologyguarantees excellent reliability and long-term stability. The humidity sensors are seamlessly coupled to a 14-bit-analog-to-digital converter and a serial interface circuit. This results in superior signal quality, a fast response time, and insensitivity to external disturbances (EMC).
Each SHT1x humidity sensor is individually calibrated in a precision humidity chamber. The calibration coefficients are programmed into an OTP memory on the chip. These coefficients are used to internally calibrate the signals from the sensors. The two-wire serial interface and internal voltage regulation allows for easy and fast system integration.
Parts List
| Label | Part Type | Properties |
|---|---|---|
| MBED1 | mbed | MBED 1768 |
| Part1 | SHT1x-Breakout | CJMCU |
Layout
Code
https://os.mbed.com/components/SHT15-temperature-and-humidity/
[codesyntax lang=”cpp”]
#include "mbed.h"
#include "SHTx/sht15.hpp"
Serial pc(USBTX, USBRX);
DigitalOut busy(LED1);
// I used p9 and p10 here but you
SHTx::SHT15 sensor(p9, p10);
int
main()
{
// Speed things up a bit.
sensor.setOTPReload(false);
sensor.setResolution(true);
while(1)
{
busy = true;
sensor.update();
busy = false;
// Temperature in celcius
sensor.setScale(false);
pc.printf("Temperature - %3.2f C\r\n", sensor.getTemperature());
// Relative Humidity
pc.printf("Humdity - %3.2f %%\r\n\n", sensor.getHumidity());
wait(5);
}
}
[/codesyntax]
Testing
Using a terminal program such as TeraTerm you should see readings like the following
Temperature – 26.06 C
Humdity – 34.90 %
Temperature – 25.94 C
Humdity – 34.78 %
Temperature – 25.90 C
Humdity – 35.28 %
Temperature – 25.82 C
Humdity – 35.20 %
Temperature – 25.70 C
Humdity – 35.61 %
Temperature – 25.62 C
Humdity – 35.53 %
Temperature – 27.54 C
Humdity – 41.73 %
Temperature – 30.26 C
Humdity – 56.96 %
Links
Temperature and humidity sensor interface board floor board adapter PCB SHT10 SHT11 SHT15 B board
