If you have worked with IOT projects that integrate with other web apps or any other types of system you probably must be dealing with 10 different languages and frameworks, it’s painful. It also gets chaotic to maintain the code base in different language and repository. In such areas of troubles, Nodejs/javascript gives out some ray of hope. In this post, we will create a chat bot that will be able to communicate with Arduino board and its connected sensor and this entire project will be in Nodejs just one language javascript. Nodejs is chosen because it excels at handles I/O operations.

In the previous article we connected Arduino UNO with ESP8266-01 and tried various AT commands to create an Access Point, making a connection to a Wifi Network, listening to the TCP port and passing message back and forth with AT commands. That was all basic tasting water, in the post we will step up the game and we will read sensor data from Arduino and send it to a central server and then will display that sensor data on the mobile client.

For the purpose of demonstration, we will use DHT11 temperature and humidity sensor and will send temperature and humidity data to the central server. For the server and mobile client, we will use Blynk which is has a server which collects sensor data from various devices and there is also Blynk mobile client which you can create a dashboard with drag and drop interface and play around with visualization of the sensor data.

If you ever heard of internet of a thing and have been fascinated by its possibilities and its promises then I am sure you must have heard of Arduino development boards. Arduino is a great piece of hardware to do some quick hardware prototyping and when you are confident with the prototype you go a step further and build more of these devices and make them work for you to do some sort of automation. Adding Wireless capability to Arduino projects will even make it more easy to install/use. In this post, I will connect the ESP8266 chip to Arduino Uno. We will see how we can create Access Point and connect to wireless networks. ESP8266 is a low-cost alternative to Arduino WiFi shield.

Browsing through Arduino projects on the internet recently I came across ACS712 current Hall sensor which can be used to measure current, it can measure both AC and DC current.I found it pretty cool so I ordered one, this post is about how we can measure AC/DC current consumed by the load connected to the power supply. So of the other applications of the sensor that comes to my mind are sensing if a device is on/off, measure instability in power supply, motor control, over current fault protection, etc.

There are lots of sensors that we can play around with Arduino but usually, they operate on 3.3v or 5v but what if you want to control high voltage circuits that don’t operate on such low voltage. Well for these types of devices we use relay circuits. There are different types of Relay circuits with based on parameters like how much current/voltage it can handle, what is the voltage required for controlling their relay etc. The relay circuit we are going to use for this post is operating on 5V and can handle device having a voltage rating of 10A-125V to 10A-230V AC and 10A-28V to 10A-30V DC.