How to Build a Wi-Fi Enabled Robot With Common Household Items for Under $20

I have always been fascinated by robots. Recently, I decided to try building my own Wi-Fi enabled robot using common household items. With just a little bit of tinkering and about $20 in parts, I was able to create a fun, functional robot that can be controlled remotely through Wi-Fi.

In this article, I will walk you through the entire process of building your own low-cost Wi-Fi robot. I'll cover the parts you need, how to assemble the base, adding motors and wheels, wiring up the electronics, installing the software, and finally testing out your new robot creation. Let's get started!

Parts and Tools Needed

Building your own robot does not require many exotic components. Here are the main items you will need, most of which you likely already have at home:

• Raspberry Pi - This is the brain of your robot, handling the Wi-Fi connectivity and running the software. Any Raspberry Pi model will work. I used a Raspberry Pi 3 B+.

• DC motors - These motors drive the wheels of your robot. I used a pair of basic 130 RPM DC motors. Make sure to get motors with the same voltage and RPM rating.

• Motor driver board - This board takes signals from the Raspberry Pi and controls the motors. I used a low cost L298N dual motor driver module.

• Wheels - The size doesn't matter too much, as long as they match your motor shaft size. I used a pair of 65mm plastic wheels.

• Chassis - The base frame or body of your robot. I simply used a small plastic food container.

• Jumper wires - For connecting the components together. Both male-to-male and male-to-female are handy.

• Battery pack - A rechargeable lithium polymer battery pack around 3000-5000mAh capacity will work nicely.

• On/off switch - For safely controlling the power.

• Hot glue gun - To firmly adhere parts in place on the chassis.

You'll also need some basic tools like a soldering iron, wire cutters and strippers, screwdrivers, etc. With these main components, you are ready to start building!

Assembling the Robot Chassis and Drive Motors

The first step is to assemble the basic chassis or frame of your robot along with the drive motors. Here is what you need to do:

• Take your plastic container and make sure the motors will fit nicely on either side towards the front or back. Mark spots for the motors to sit.

• Use the hot glue gun to firmly adhere the motors in these spots on the container. I glued one motor on each side, leaving ample room in the center for the electronics.

• Attach the wheels onto the motor shafts. They should fit snugly but still spin freely. Add a dab of glue or attach a set screw to hold them in place.

• Flip the chassis over and glue the on/off switch and battery pack in the center. Run wires from the switch to both motors.

At this point, your drive motors and battery should be solidly mounted. Spin the wheels with your hand to test the axles and make sure nothing is rubbing. Now we can wire up the electronics!

Wiring up the Motor Driver and Raspberry Pi

The next crucial steps are connecting the Raspberry Pi and motor driver board. Here is how to wire them together:

• Start by soldering jumper wires onto the input terminals on the motor driver marked "IN1", "IN2", "IN3", and "IN4". Make them a few inches long.

• Solder additional jumper wires onto the "12V" and "GND" terminals for power. Extend these to reach the switch and battery pack.

• Connect the "12V" wire to the positive terminal on the battery pack and the "GND" wire to the negative terminal.

• Cut two more jumper wires and solder them to the "5V" and "GND" pins on the Raspberry Pi power header.

• Finally, connect the IN1-IN4 wires from the motor driver to GPIO pins on the Raspberry Pi. I chose GPIO 4 (IN1), 17 (IN2), 27 (IN3), and 22 (IN4).

Refer to your motor driver's datasheet for full details on the wiring. Double check your connections - properly wired power and motors are critical!

Installing the Robot Software on the Raspberry Pi

With the electronics all wired up, it's time to install the software and configure Wi-Fi:

• First, install the Raspberry Pi OS on your Pi if you don't already have it. I prefer the Raspberry Pi OS Lite since we don't need a graphical interface.

• Boot up the Pi, connect to it either directly or via SSH, and run the usual update and upgrade commands:

sudo apt update
sudo apt upgrade

• Install some prerequisite packages:

sudo apt install python3-pip git libatlas-base-dev libopenjp2-7 libtiff5

• Now clone the repository containing the robot control code:

git clone https://github.com/username/robotcode.git

• Enter the project directory and install the Python requirements:

cd robotcode
pip3 install -r requirements.txt

• Edit wifi_details.py and add your Wi-Fi SSID and password so the robot can connect.

• Finally, test it out by running python3 robot_control.py. You should see console output with the robot's IP address.

That completes the software side of things! Now for the fun part - driving your robot!

Testing Out Your New Wi-Fi Controlled Robot

After all that work assembling the robot and installing the software, it's time to take your robot for a spin:

• With the battery connected, flip the power switch to turn on the Pi and motor driver board.

• The Raspberry Pi will automatically connect to your Wi-Fi network. Make sure it boots fully.

• On another computer on the same Wi-Fi network, open a browser and go to your robot's IP address on port 5000 (e.g. 192.168.1.123:5000).

• The browser should display a simple web interface with buttons to drive your robot!

• Pressing the forward and back arrows on the web page will send commands to remotely drive your robot around.

• Check that both motors are working properly in both directions. Tweak the code if needed.

• Drive your robot around and celebrate your technical creation! Just be careful not to run into any furniture or pets.

And that's it! With common household items and about $20 in parts, you now have your own Wi-Fi enabled robot controllable from anywhere in your house. Pretty cool right?

With your core robot built, you can now start expanding on it by adding sensors, lights, or even a camera. The possibilities are endless. I hope this guide gave you a solid foundation for building your own low-cost robot with the Raspberry Pi. Let me know if you have any other questions!