OneWire Temperature Sensing with PSOC™ 6 Arduino and DS18B20

Introduction

You've just started a new project to automate your home's climate control system, and you need a reliable way to measure the temperature in each room? You've heard that the DS18B20 temperature sensor is a great option, but you're not sure how to get started?In this tutorial, we'll take you step-by-step through the process of getting the DS18B20 sensor connected to your PSOC™ 6AI Evaluation Kit using Arduino.

The DS18B20 communicates over the OneWire protocol, which allows multiple sensors to share a single data line, making it ideal for scalable temperature monitoring setups. With Arduino support available for PSOC™ 6, you can develop projects faster while utilizing the advanced features of the hardware.

📘 Understanding OneWire with PSOC™ 6

The OneWire protocol is a single-wire communication system developed by Dallas Semiconductor, and it simplifies sensor interfacing significantly. With only one data pin, you can connect multiple sensors, each identified by a unique address.

PSOC™ 6 handles the precise timing required for OneWire communication efficiently. Additionally, with Arduino compatibility, implementing it is straightforward using the available libraries.

🔧 Hardware Requirements

The DS18B20 is a digital temperature sensor that utilizes the OneWire protocol to communicate with devices. To connect the DS18B20 to the PSOC™ 6 AI Evaluation Kit, follow these steps:

🔌 Circuit Connections

DS18B20 VCC Pin - PSOC™ 6 VCC Pin

DS18B20 GND Pin - PSOC™ 6 GND Pin

DS18B20 DQ Pin - PSOC™ 6 P9_2 ( Any digital IO pin) + 4.7kΩ pull-up to 3.3V

💻 Software Setup

First, make sure that you downloaded the PSOC™ 6 for Arduino. If not, no worries!, you can check this protip: PSOC™ 6 for Arduino where it is all explained and then ensure to choose the board CY8CKIT-062S2-AI and the correct serial port.

The 1-Wire communication protocol used by the DS18B20 sensor is a bit complex, since it has a lot of raw calculations. Fortunately, a convenient library called DallasTemperature is available that makes such things much easier. To install the library:

• Open the Arduino IDE and navigate to the "Sketch" menu.
• Select "Include Library" and then "Manage Libraries".
• Search for "DallasTemperature" and click "Install".

To work properly, the DallasTemperature library needs to be paired with another library called "OneWire".

• Search for the "OneWire" library in the library manager and click "Install"

With both libraries installed, you’ll be ready to start working with your DS18B20 temperature sensor!

We will be using one of the examples provided by the DallasTemperature library.

To access the sketch:

• Go to File > Examples> DallasTemperature> Simple

1. Library and Object Initialization

#include <OneWire.h>
#include <DallasTemperature.h>

#define ONE_WIRE_BUS 2
OneWire oneWire(ONE_WIRE_BUS);

DallasTemperature sensors(&oneWire);

An instance oneWire is created with pin 2 specified as the data line ie, P9_2 of PSOC. Then we create a DallasTemperature object and pass oneWire object as reference.

⚙️ 2. Setup Function

void setup(void)
{
    // start serial port
    Serial.begin(9600);
    Serial.println("Dallas Temperature IC Control Library Demo");

    // Start up the library
    sensors.begin();
}

Initializes the serial monitor to output temperature readings and debugging information. Then we use sensors.begin( ) which scans the onewire bus to detect any connected sensors.

🔁 3. Main Loop

void loop(void)
{
    // request to all devices on the bus
    Serial.print("Requesting temperatures...");
    sensors.requestTemperatures(); // Send the command to get temperatures
    Serial.println("DONE");
    delay(1500);
   
    float tempC = sensors.getTempCByIndex(0);
    // Check if reading was successful
    if (tempC != DEVICE_DISCONNECTED_C)
    {
    Serial.print("Temperature for the device 1 (index 0) is: ");
    Serial.println(tempC);
}
else
{
    Serial.println("Error: Could not read temperature data");
}
}

This continuously requests temperature to all devices on the bus and then prints the temperature if the reading was successful.
Here we call sensors.requestTemperatures() to perform a temperature conversion on all sensors on the wire . Once the conversion is done we call sensors.getTempCByIndex(deviceIndex) to read the temperature from the sensor.

The deviceIndex is a number that tells the Arduino which sensor we want to read from the 1-Wire bus. Since we only have one sensor connected, we use 0 to refer to it.

🚀 Upload & Test

Now that you've written the code, you can upload it to your PSOC™ 6 AI Kit and test the system. To do this, follow these steps:

• Connect the PSOC™ 6 AI Kit to your computer using a USB cable.
• Open the Arduino IDE and select the correct board and serial port.
• Upload the code to the PSOC™ 6 AI Kit.
• Open the serial console and observe the temperature readings.

🏁 Conclusion

You now have a working temperature sensing system using the PSOC™ 6 AI Kit and a DS18B20 sensor over OneWire.

This setup provides a flexible base that can be expanded in several ways:

• Adding more sensors on the same line.
• Logging temperature data.
• Triggering alerts or controls based on thresholds.

Let us know how you’re using it — whether it’s for smart agriculture, home automation, or system diagnostics.