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14. Networking and communications

Assignment

individual assignment:
design, build, and connect wired or wireless node(s)
with network or bus addresses
group assignment:
send a message between two projects

Learning outcomes

Demonstrate workflows used in network design
Implement and interpret networking protocols

nueval-Check List

Described your project using words/images/diagrams/schematic screenshots.
Explained the programming process/es you used.
Outlined problems and how you fixed them
Included design files (or linked to where they are located) and original code

Group work

FabAcademy2019-FabLab Kannai lab site

My work

This week, I made 3 boards and tried to communicate among these boards. Based on hello.I2C.45.bridge for the master, and hello.I2C.45.node for slave.

Here’s parts list

Using fabmodules for creating a data for mill

Milled by MDX-15

I milled master and slave boards at once

I coded the following for master and for slave. Master sends signal and when slaves get signal, their LED blink.

When I tried to write through FabISP, it didn’t go well. When I supplied electricity through USB tiny and write throuh FabISP, I successfully wrote it.

#include <Wire.h>
#include <SoftwareSerial.h>                  

#define SLAVE_1 1
#define SLAVE_2 5

SoftwareSerial mySerial(3, 4); // RX, TX    

void setup() {
  Wire.begin(); // join i2c bus (address optional for master)
  mySerial.begin(9600);
  mySerial.println("start");
}

byte x = 0;

void loop() {
  Wire.beginTransmission(SLAVE_1); // transmit to address
  Wire.write(x);              // sends one byte
  Wire.endTransmission();    // stop transmitting
  delay(1000);
  Wire.beginTransmission(SLAVE_2); // transmit to address
  Wire.write(x);              // sends one byte
  Wire.endTransmission();    // stop transmitting
  delay(1000);
  x = (x == 0) ? 1 : 0;
}

#include <Wire.h>

#define SLAVE_ADDR 5           // i2c slave address (1)
#define LED_PIN 4

void setup() {
  // put your setup code here, to run once:
  pinMode(LED_PIN,OUTPUT);
  Wire.begin(SLAVE_ADDR);      // init I2C Slave mode
  Wire.onReceive(receiveEvent); // register event
}

void loop() {
  delay(100);
}
volatile byte msg = 0; 
void receiveEvent(int howMany){
  while (0 < Wire.available()) {
    msg = Wire.read();
    if (msg == 0){
      digitalWrite(LED_PIN, HIGH);
    }else if (msg == 1){
      digitalWrite(LED_PIN, LOW);
    }else{
      msg = 0;
    }
  }
}

#include <Wire.h>

#define SLAVE_ADDR  1           // i2c slave address (1)
#define LED_PIN 4

void setup() {
  // put your setup code here, to run once:
  pinMode(LED_PIN,OUTPUT);
  Wire.begin(SLAVE_ADDR);      // init I2C Slave mode
  Wire.onReceive(receiveEvent); // register event
}

void loop() {
  delay(100);
}
volatile byte msg = 0; 
void receiveEvent(int howMany){
  while (0 < Wire.available()) {
    msg = Wire.read();
    if (msg == 1){
      digitalWrite(LED_PIN, HIGH);
    }else if (msg == 0){
      digitalWrite(LED_PIN, LOW);
    }else{
      msg = 0;
    }
  }
}

Video

Here’s the video the boards communicating.