DIY a Simple Tricycle Robot Car Based on ESP8266 Controlled by Smartphone

This tutorial will show you how to make a simple robot car at home using basic electronic components.

The car can be controlled via smartphone, and not limited to four directions.This is a very interesting project for beginners, and it won’t take much time to complete. Through it, you can not only learn how to build a vehicle, but also understand the role of motors in vehicle operation, as well as some basic electronic knowledge, programming practice, and even some physics knowledge.

Required Materials

• NodeMCU or ESP8266 board
• L298N motor driver
• BO motor (reduction motor)
• Wheels
• Cardboard
• Hot glue and strong glue
• Jumper wires
• Lithium-ion battery and battery holder
• Switch

Here’s what you’ll need if you want to make a cool version as an alternative

• 3D printer
• PLA filament
• Tinkercad application
• Cura slicing software

Production Steps

Prepare the Base Plate

This project provides two ways to make the base plate: you can choose to 3D print it or make it out of cardboard. (STL files can be downloaded at the end of the article)

If you choose to 3D print the base plate, you need to use the Tinkercad application for design and then print. If you choose cardboard, you need to make a template based on the design reference standards of the BO motor, then draw the template outline on the cardboard and cut out the base plate.

Make the Circuit Diagram

The circuit diagram of the entire robot car is as shown in the tutorial. No breadboard is used, but jumper wires are directly used to connect the components.

Before establishing connections, make sure to connect the battery’s ground wire to the motor driver and NodeMCU’s GND. The positive terminal of the battery holder connects to the 12v slot of the motor driver, and the 5v of the motor driver connects to the Vin of the NodeMCU board. Now, the communication connections between the motor driver and NodeMCU are as follows:

• ENA to GPIO14 (D5)
• ENB to GPIO12 (D6)
• IN_1 to GPIO15 (D8)
• IN_2 to GPIO13 (D7)
• IN_3 to GPIO2 (D4)
• IN_4 to GPIO0 (D3)

Finally, we connect the wiring interface of the BO motor to the motor connection slot on the motor driver. This way, the motor driver can control the operation of the BO motor.

Write Arduino Code

Connect the development board to the computer, open Arduino IDE, then copy and paste the code provided in the tutorial into the IDE. (The code can be downloaded at the end of the article)

If you want to set a custom name for WiFi, you can edit it in the code. If you are not completely clear about this, it is recommended not to make any changes.

Click on the board, select the ESP8266 module board, now check the correct serial port (COM) number, then click the upload code button.

After a while, the code will be uploaded to the board, and now the board has the code.

After completing this step, test the project with the power supply from the battery. When you turn on the switch, if everything is normal, the LED indicator on the NodeMCU will light up, and you will see the Wi-Fi name on your phone.

Add Front Wheel

The robot car is a tricycle, with one front wheel that rolls freely, while the other two wheels are controlled by the motor shaft.

Now for this we use a simple mechanism, and all we need to do is use a straw or a piece of tube. If you cannot find any tubes, you can make one yourself by rolling a strip of paper into a tube shape and securing it with strong glue.

Place it on the small tip of the cardboard and secure it with strong glue.

Then you can add the wheels and lock it from the center with the tube or homemade paper tube!

The basic model is ready, now all we need to add are the electronic components, and this is not a complicated task.

Complete Assembly

Place a drop of hot glue on the cardboard, then place the lithium-ion battery holder with the battery on it. Next, secure the motor driver to the cardboard, and connect the wires of the BO motor to the slots on the driver. Finally, place the NodeMCU board.

How to Use

Setting up the connection between the robot car and the smartphone (control device) is very simple. Use Wi-Fi to access the hotspot, first turn on Wi-Fi on your phone, then turn on the robot car, and you will see the Wi-Fi name you set for the vehicle on your phone, connect to the network. Then, you can open the application that is pre-installed on your phone, so you can control the robot car via a digital screen remote control.