Networking and communications

Objectives for Week 11

Individual Assignment

• Design, build, and connect wired or wireless node(s) with network or bus addresses and local input &/or output device(s)

Group Assignment:

• Send a message between two projects

Group Assignment

As part of the group assignment, we calculated the power consumption of Sg90 servo using a bench power supply. The SG90 servo draws a maximum power of 1.5W

Group assignment link.

Individual Assignment

This week, I worked on connecting three boards, where one board functioned as the controller, and the other two operated as responders. I utilized the I2C protocol to establish communication between them. The goal was to control both responder boards using the controller.

I2C

I2C (Inter-Integrated Circuit) is a communication protocol that allows multiple devices to communicate with each other using just two wires: one for data (SDA) and one for the clock signal (SCL). It is commonly used to connect microcontrollers, sensors, and other peripherals. In an I2C setup, one device acts as the controller, sending instructions, while other devices act as responders, receiving and responding to those instructions. This makes it efficient for connecting multiple components with minimal wiring.

Like UART communication, I2C only uses two wires to transmit data between devices:

• SDA (Serial Data)- The line for the master and slave to send and receive data.


• SCL (Serial Clock)- The line that carries the clock signal.

To know more about I2C follow this link.

I made a developement board in the Electronics Design week using the ATtiny3216 and made a board using XiaoESP32S3 in the Output week. Both the boards have I2C connections as well.

Initially I decided to communicate these boards. If it works well I can design and produce new board.

For understanding more about the communication I followed Midhun's documentation. And I got the basic idea of how communication between two boards works and I got the basic structure of the codes for the two boards as well. So I copied the code for the responder board and flashed it into the ATtiny3216 developement board I designed earlier using a programmer. Midhun had a button on his board and he switches the board using the button. I my master board I don't provided a button, So I just copied the code and using the helpof Chat GPT I wrote a code to toggle the LED state of the responder board with a delay of 1 second. This code was flashed into the Xiao ESP32S3 board. Using the jumper wires I connected both the boards and the LED of the responder board starts blinking. So the testing was sucessful so that I can make a new board and understand the codes as well.

Codes

                #include <Wire.h>

                    const int slaveAddress = 8; // I2C address of the ATtiny1616
                    int ledState = 0;  // Toggle state (0 = OFF, 1 = ON)
                    
                    void setup() {
                      Wire.begin(); // Initialize I2C as master
                    }
                    
                    void loop() {
                      // Send command to toggle LED on the slave device
                      Wire.beginTransmission(slaveAddress);
                      Wire.write(ledState);
                      Wire.endTransmission();
                    
                      // Toggle LED state for next loop
                      ledState = !ledState;
                    
                      delay(1000); // Wait for 1 second
                    }
                    
                    
            

                #include <Wire.h>

                    const int ledPin = 12; 
                    int ledState = LOW;   
                    
                    void setup() {
                      pinMode(ledPin, OUTPUT); 
                      digitalWrite(ledPin, ledState);
                      
                      Wire.begin(8); 
                      // Wire.begin(9); // Uncomment this and comment the above line for the second slave with address #9
                      Wire.onReceive(receiveEvent); 
                    }
                    
                    void loop() {
                      
                      delay(100); // Small delay for stability
                    }
                    
                    // Function to handle incoming data from the master
                    void receiveEvent(int howMany) {
                      while (Wire.available()) {
                        int command = Wire.read(); 
                        if (command == 0) {
                          ledState = LOW; 
                        } else if (command == 1) {
                          ledState = HIGH;
                        }
                        digitalWrite(ledPin, ledState);
                      }
                    }