Week16 - System Integration

info

Writing on '2025.5.14'.

The task of the assignment

Design and document the system integration for your final project

Progress of my Final Project

Lots of progresses are recorded in my page of final project.

The following works are recorded for my final project:

Cat shelter Modeling and layout
System Design
User Interface

Struture of my final project

Here's first struture design of my final project.

In my version 1 design, pressure sensors are used for sensing the weight of food and water to estimate the remaining food and water, and the environment sensing data such as temperature, position, water level in bowl will be transferred to the PC laptop through ESP-NOW protocol.

After studying for networks and interface, I can transfer the sensing data or control the hardware through MQTT protocol. Then I can display the sensing data on the website.

Here's my new structure design of my final project.

I divided the final project in two parts:

Environment sensing
Auto Feeder

Cat Shelter Modeling and Layout

Based on the week7 assignment, a cat shelter is milled as parts of my final project.

The auto feeder/water bowl will be placed in inner part of the shelter. The environment sensing part will be placed at the top part of the shleter.

System Design

Here's the material list of my system.

Sensor/Microcontroller	Function	Price	Count	Link
XIAO ESP32C3	Controllers for getting sensor data	9.99	2	link
RYS352A GNSS Antennia	Getting position data	10.00	1	link
HX711 load cell sensor	Sensing remain cat food	6.79	1	link
WWZMDiB 12 Water level sensor	Sensing remain water	6.99	1	link
HC-SR504 Ultrasonic sensor	Detect the cat inside the shelter	9.99	1	link
28BYJ-48 Stepper Motor	For activator of auto feeder	14.59	1	link

In environment sensing part, BDS Antennia, Ultransonic sensor and temperature sensor are used for sensing the position data, cat is inside the shleter or not, the environment temperature, respectively. The sensing data will be uploaded to my website page through MQTT protocol.

In Auto Feeder part, there are two bowls for food and water. A cell load sensor is used for sensing the weight of remaining food. A water level sensor is used for sensing the water level of remaining water. The auto feeder can feed the food automatically when the weight of food bowl is less than 20% full-weight of food bowl or activate the auto feeder by a button in my website page.

Interface

Environment sensing

The sensing data of environment sensing part is received through MQTT protocol. I can observe the sensing data through MQTTX software.

In this part, 1 HC-SR504 ultrasonic sensor, 1 BDS Antennia and 1 DHT11 Sensor are used for sensing the environment.

In order to tidy up the cables of sensors, a smaller PCB is designed and easier to tidy up the cables.

It's simple design: the pins in left hand side are IO pins, the pins in right hand side are power pins.

It can be used for tidy up the cables, here's a example:

The designed PCB will be inserted into a designed control box. Here's the design in solidworks.

The sensing data of 3 sensors will be transferred through MQTT protocol. I observe the transferred data by MQTTX.

The format of the data sentence is ( temperature cat_state longitude latitude ).

Environment sensing code

#include "DHT.h"
#include <SoftwareSerial.h>
#include <WiFi.h>
#include <PubSubClient.h>

#define DHTPIN D3
#define DHTTYPE DHT11

DHT dht(DHTPIN, DHTTYPE); // constructor to declare our sensor
SoftwareSerial MySerial(D2, D1);

int Echo = D4;
int Trig = D5;
int duration=0, distance=0;
bool cat_state = 0;
String NMEA_BD = "";

// Replace the next variables with your SSID/Password combination
const char* ssid = "MSC-Person";
const char* password = "Msc@2333";
// Add your MQTT Broker IP address, example:
//const char* mqtt_server = "192.168.1.144";
const char* mqtt_server = "broker.emqx.io";

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (50)
char msg[MSG_BUFFER_SIZE];
int value = 0;


void setup_wifi() {

  delay(10);
  // We start by connecting to a WiFi networka
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Create a random client ID
    String clientId = "XIAO-ESP32-Client-";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    // if (client.connect(clientId.c_str())) {
    if (client.connect(clientId.c_str(), "", "")) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      //client.publish("fabacademy/dionTest/Temperature", "hello world");

      // ... and resubscribe
      client.subscribe("fablab/msc/sensor_series");  //subscribe topic
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  MySerial.begin(9600); //Set 9600 baud rate to get the latitude/longitude information only.
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);

  pinMode(Trig, OUTPUT);
  pinMode(Echo, INPUT);
  dht.begin();

  #if defined(__AVR_ATtiny85__) && (F_CPU == 16000000)
    clock_prescale_set(clock_div_1);
  #endif
}

void loop() {
  if(!client.connected()){
    reconnect();
  }
  client.loop();

  long now = millis();
  if(now - lastMsg > 1000){
    lastMsg = now;

    digitalWrite(Trig,HIGH);
    delayMicroseconds(10);
    digitalWrite(Trig,LOW);
    duration=pulseIn(Echo,HIGH,4000); 
    distance=duration*0.0343/2;  
    if(distance == 0){
      cat_state = 0;
    }
    else if(distance > 0 && distance <= 30){
      cat_state = 1;
    }
    if(MySerial.available()!=0){
      NMEA_BD = String(MySerial.readStringUntil('\n'));
    }else{
      NMEA_BD = "0.0, 0.0";
    }
    float t = dht.readTemperature();
    /*Serial.print("Temperature: ");
    Serial.print(t);
    Serial.print(" Cat State: ");
    Serial.print(cat_state);
    Serial.print(" Position Data: ");
    Serial.println(NMEA_BD);*/
    String output_data = String(t) + " " + String(cat_state) + " " + String(NMEA_BD);
    Serial.println(output_data);
    client.publish("fablab/msc/sensor_series", output_data.c_str());
  } 
}

Then, split the data into 4 parts and display on the website.

It may spend lots of time to re-design the UI.

Link

Sensing data interface -- 1st version

The task of the assignment​

Progress of my Final Project​

Struture of my final project​

Cat Shelter Modeling and Layout​

System Design​

Interface​

Environment sensing​

Link​