Arduino DS18B20 Thermometer on iOS or Android

Step 1: Introduction

In this Instructable I am going to attempt to show you how to put together a little project to use the Blynk app (optainable at to display the temperature remotely on a iOS or Android device.

I came across an posting on my Google+ where somebody required some help with this. It looked interesting, so I decided to have a try myself.

This is my first attempt to write an Instructable. I have found many articles published here useful. So I thought it is time to do my part.

The main parts I used are:

Arduino UNO clone

Ethernet shield

Dallas DS18B20 sensor

A 4k7 resistor is also required as a pull-up resistor for the data line.

Optional Breadboard

An iOS or Android device

Step 2: The DS18B20 Sensor

The DS18B20 sensor connections are as follows, looking at the label:

Left leg = GND

Middle leg = Data

Right leg = 5 V

Step 3: Let’s Start

I used a mini breadboard just to connect the pull-up resistor to the 5 V and Data connection. You could just solder the resistor straight onto the legs.

Step 4: Wiring

That is how it is all wired up.

Vcc -> 5V

GND -> Gnd

Data -> pin 7

4k7 resistor between 5 V and Data legs

Step 5: Getting Some Code to Work

I don’t believe in reinventing the wheel. Download the library from the Blynk website and install it into your Arduino libraries folder.

I used the BlynkBlink scetch from the Blynk examples and the DS18x20_temperature example from the OneWire Library. I combined the two into one sketch. I did change the pin for the DS18B20 data into the Arduino to pin 7. The reason for this is because pin 10 is used by the Ethernet shield. I also added a line to the end of the DS18x20 data processing section. Blynk.virtualWrite(V5, celsius); This sends the celsius result. You can change that to Blynk.virtualWrite(V5, fahrenheit); to send the Fahrenheit result.

Step 6: Result

On the device side, you have to use V5 as an input and set up the range. Detailed instructions relating to the software side and iOS and Android device setup are in the sketch and on the Blynk website. Once you worked out the basics, it is easy to change it to use a different display mode on your device, like “Value Display”, “Gauge”, “LCD” and “Graph”.

I want to thank all the people who made this possible. The people who designed and made the hardware and wrote the software that I have used for this project. Without them life would be different.

Do not hesitate to make suggestions and ask questions, if you get stuck. I’m still learning how to write a good Instructable.

Read more: Arduino DS18B20 Thermometer on iOS or Android

About The Author

Ibrar Ayyub

I am an experienced technical writer holding a Master's degree in computer science from BZU Multan, Pakistan University. With a background spanning various industries, particularly in home automation and engineering, I have honed my skills in crafting clear and concise content. Proficient in leveraging infographics and diagrams, I strive to simplify complex concepts for readers. My strength lies in thorough research and presenting information in a structured and logical format.

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