Getting Started with the RobDuino Module in Early Robotics

Robotics is a fantastic way to introduce students to electronics, programming, and system design. The RobDuino module was developed specifically for early robotics education using the Arduino UNO. It simplifies connections between the microcontroller and common electronic components such as sensors, DC motors, and LCDs. This chapter explains the hardware features, provides step-by-step setup instructions, and offers sample projects and exercises to deepen your understanding.

Introduction

The RobDuino module is designed to make it easier to connect sensors, actuators, and other components to an Arduino UNO. By integrating an H-bridge driver on the digital pins and providing accessible screw terminals, it allows for quick prototyping and experimentation. In this chapter, you will learn:

  • Key Hardware Features: How the module’s pins are arranged and their specific functions.
  • Wiring Techniques: How to correctly connect sensors, motors, and other devices.
  • Programming Basics: How to use Arduino functions like digitalWrite(), analogWrite(), digitalRead(), and analogRead() with the module.
  • Sample Projects: Practical examples such as blinking an LED and controlling a DC motor.
  • Self-Assessment: Questions to test your understanding.

Hardware Overview

Before diving into the projects, it is essential to understand the RobDuino module’s layout and functionality.

Digital Output Pins (D0–D7)

  • H-Bridge Driver: Each digital pin (D0 to D7) is equipped with an H-bridge driver. These pins are intended to be used as digital outputs only.
  • Usage: Use digitalWrite(pin, HIGH) or digitalWrite(pin, LOW) to set the voltage level.
  • PWM Capability: On pins D6, D5, and D3, you can also use the analogWrite(pin, value) function to output a Pulse Width Modulated (PWM) signal. This is useful for controlling the speed of motors or the brightness of LEDs.

Analog and Digital Input Pins (A0–A5)

  • Versatile Use: The analog pins can function as either digital or analog inputs.
  • Digital Read: Use digitalRead(pin) to determine if the voltage is HIGH (+5V) or LOW (0V).
  • Analog Read: Use analogRead(pin) to obtain the actual voltage level (a value between 0 and 1023).
  • Special Note: Pins A4 and A5 are also equipped with jumpers connected to GND. This configuration can be beneficial for certain sensor setups and helps to stabilize the readings.

Power and Control Terminals

  • +5V and GND Terminals: These screw terminals are used to power sensors and other modules.
  • Reset Button: Resets the Arduino UNO, restarting the currently loaded program.
  • ENABLE Switch: This switch can disable all outputs on pins D0–D7, which is especially useful for safely disconnecting actuators (e.g., DC motors) during testing or when not in use.

Wiring and Setup

Connecting the RobDuino Module

  1. Digital Connections:
    • Connect your output devices (LEDs, motors, etc.) to the screw terminals labeled D0–D7.
    • For PWM control, make sure your device is connected to D3, D5, or D6.
  2. Analog Connections:
    • Attach sensors (such as light sensors, potentiometers, etc.) to the screw terminals labeled A0–A5.
    • Remember: if using A4 or A5, the built-in jumper to GND might affect your circuit, so consult the sensor’s datasheet if necessary.
  3. Powering Devices:
    • Use the +5V and GND terminals on the RobDuino module to supply power to sensors or other low-voltage devices.
  4. Control Elements:
    • Familiarize yourself with the Reset button for restarting your program.
    • Use the ENABLE switch to disable outputs when you need to prevent accidental activation of actuators.

Safety Tips

  • Double-check connections before powering the system.
  • Use current-limiting resistors when connecting LEDs to avoid damaging components.
  • Ensure proper grounding to prevent erratic sensor readings.

Programming Examples

Programming the RobDuino module is very similar to programming a standard Arduino UNO. Here are a few example sketches to illustrate its use.

Example 1: Blinking an LED on a Digital Output Pin 

// Connect an LED (with a current-limiting resistor) to the D0 terminal.

void setup() {
  // Set digital pin 0 as an output
  pinMode(7, OUTPUT);
}

void loop() {
  digitalWrite(7, HIGH);   // Turn the LED on
  delay(1000);             // Wait for 1 second
  digitalWrite(7, LOW);    // Turn the LED off
  delay(1000);             // Wait for 1 second
}

Example 2: Controlling LED Brightness with PWM 

// Connect an LED to the D6 terminal which supports PWM

void setup() {
  // Set digital pin 6 as an output
  pinMode(6, OUTPUT);
}

void loop() {
  // Increase brightness
  for (int brightness = 0; brightness <= 255; brightness++) {
    analogWrite(6, brightness);
    delay(10);
  }
  
  // Decrease brightness
  for (int brightness = 255; brightness >= 0; brightness--) {
    analogWrite(6, brightness);
    delay(10);
  }
}

Example 3: Reading an Analog Sensor 

// Connect a potentiometer or any analog sensor to the A0 terminal

void setup() {
  Serial.begin(9600);  // Initialize serial communication for debugging
}

void loop() {
  int sensorValue = analogRead(A0);  // Read the analog value from sensor
  Serial.println(sensorValue);       // Print the sensor value to the Serial Monitor
  delay(500);                        // Wait half a second before the next reading
}

Example 4: Controlling a DC Motor Using the H-Bridge 

// Assume the DC motor is connected via an H-bridge on digital pins D7 (direction) and D6 (PWM speed control)

void setup() {
  pinMode(7, OUTPUT); // Motor direction control
  pinMode(6, OUTPUT); // PWM speed control
}

void loop() {
  // Set motor direction to forward
  digitalWrite(7, HIGH);
  
  // Ramp up the motor speed
  for (int speed = 0; speed <= 255; speed++) {
    analogWrite(6, speed);
    delay(10);
  }
  
  // Run at full speed for 2 seconds
  delay(2000);
  
  // Ramp down the motor speed
  for (int speed = 255; speed >= 0; speed--) {
    analogWrite(6, speed);
    delay(10);
  }
  
  // Brief pause before reversing the motor
  delay(500);
  
  // Change motor direction to reverse
  digitalWrite(7, LOW);
  
  // Repeat the speed ramping for reverse motion
  for (int speed = 0; speed <= 255; speed++) {
    analogWrite(6, speed);
    delay(10);
  }
  
  delay(2000);
  
  for (int speed = 255; speed >= 0; speed--) {
    analogWrite(6, speed);
    delay(10);
  }
  
  delay(500);
}

Sample Projects

Project 1: LED Blinker

  • Objective: Understand basic digital output.
  • Components: LED, resistor, wires.
  • Procedure: Connect the LED to terminal D0. Upload the blinking LED sketch (Example 1). Observe the LED turning on and off at one-second intervals.

Project 2: Motor Speed Controller

  • Objective: Learn how to control a motor’s speed and direction.
  • Components: DC motor, H-bridge (integrated on the module), external power supply (if required), wires.
  • Procedure: Connect the motor as indicated in Example 4. Experiment with changing the PWM values and delay times to observe variations in motor speed and behavior.

Project 3: Analog Sensor Monitor

  • Objective: Acquire and monitor analog sensor data.
  • Components: Potentiometer or light sensor, wires.
  • Procedure: Connect the sensor to terminal A0. Use Example 3 to read sensor values and view the data on the Serial Monitor.

1.6 Self-Assessment Questions

  1. Digital Outputs:
    • What is the primary function of the digital pins D0–D7 on the RobDuino module?
      (Hint: Consider their connection to the H-bridge drivers.)
  2. PWM Capability:
    • Which digital pins support PWM, and why is PWM useful in robotics?
  3. Analog Input:
    • How do you obtain a numerical value from an analog sensor connected to the RobDuino module?
      (Which function is used, and what is the typical range of values?)
  4. Enable Switch:
    • What is the purpose of the ENABLE switch on the module, and how does it affect connected actuators?
  5. Ground Jumpers on Analog Pins:
    • Why might pins A4 and A5 have jumpers connected to GND, and how can this affect sensor operation?

Chapter Summary

  • Module Overview: The RobDuino module is a powerful tool designed for early robotics education, integrating an H-bridge on digital pins and providing accessible screw terminals.
  • Digital vs. Analog: Digital pins (D0–D7) are intended as outputs (with PWM available on D3, D5, and D6), while analog pins (A0–A5) are versatile and can be used for digital or analog inputs.
  • Power and Control: The module includes dedicated +5V and GND terminals, a reset button for rebooting the system, and an ENABLE switch for safely managing actuator outputs.
  • Programming: Standard Arduino functions (digitalWrite(), analogWrite(), digitalRead(), and analogRead()) are used to interface with the module, making it accessible to beginners.
  • Practical Projects: Through projects like LED blinking, motor control, and sensor monitoring, students can gain hands-on experience in electronics and robotics.

By mastering these basics, you lay a solid foundation for exploring more complex robotics projects in the future. Use the provided examples and self-assessment questions to test your knowledge and reinforce your learning.

Happy Robotics!