Arduino Voltage Reader

The project uses johnny-five to read the voltage from an Arduino. The voltage value is displayed on the webpage using websockets.

The code also uses the canvas gauges that shows the voltage input to the maximum permitted voltage in terms of percentage value. The change in voltage is reflected by the gauge animation.

Installing NodeJS

For installation click here.

Installing Dependencies

Browse inside the ArduinoVoltageReader directory and execute the following to install node modules:

npm install

Arduino Firmware

For using the johnny-five with Arduino, upload the StandardFirmata on your arduino.

StandardFirmata can be accessed by opening the Arduino IDE and following the steps:

File > Examples > Firmata > StandardFirmata

If you are using Arduino Nano make sure you follow the steps before uploading StandardFirmata on your board.

Tools > Processor > ATmega328P (Old Bootloader)

Arduino Instructions

The maximum voltage value permitted in Arduino Nano's analog Pin is 5V.

.env files

All the configuration variables are stored in .env file.

This is a node dependency.

Following command loads the node dependency:

require('dotenv').config();

The values stored in .env file are in key=value pairs.

The value is stored in string. So, it is necessary to use parseInt() to convert string to int.

Creating .env file

To create a .env file using GNU nano, enter the following command in terminal inside ArduinoVoltageReader directory.

nano .env

A nano text editor opens up. Type the following code:

# Maximum voltage to read is 5V.
MAX_VOLTAGE=5

# Select the analog pin on the Arduino
ANALOG_PIN=6

# Port for the server
PORT=4000

Press Ctrl + X to exit Nano.

Alternatively, use any code editor and create a file named .env and copy the upper mentioned code.

Running

• Browse in the directory using command prompt or terminal
• Connect the Arduino to your computer
• Run node index.js

Running on Raspberry Pi

Installation steps

• Clone this repository by using git clone <repo>.

• Browse inside the project directory by typing cd ArduinoVoltageReader.

• Once inside the ArduinoVoltageReader directory, install node modules by typing npm install.

• Create a .env file by typing nano .env

  • A text editor will open.

  • Copy the code mentioned in Creating .env file.

  • Once the code is copied, save by pressing Ctrl + X.

Connecting Arduino to Raspberry Pi

• Connect Arduino with Raspberry Pi with the USB.

• Attach the positive terminal of the voltage source to the Analog Pin selected in .env file (In this case Analog Pin 6 A6).

• Attach the negative terminal of the voltage source to any ground GND pin on Arduino.

Launching the express server on Raspberry Pi

• Make sure you are in the directory ArduinoVoltageReader.

• Launch the express server by typing: node index.js.

• Copy the IP address displayed in the terminal.

Viewing the display on webpage

• Use a chromium browser.

• Copy the IP address from the terminal into the search bar and go.

• The dial gauge should appear.

THE GAUGE DOES NOT DISPLAY ANY CHANGES

• Terminate the server by pressing Ctrl + C in the terminal.

• Restart the server by typing node index.js.

• Refresh the browser.