ESP32

Objective:

• Ultrasonic Sensor will measure distance
• ESP32 will be used to broadcast distance data to a webpage live
• Webpage will display distance information as a dynamic graphic

Circuit

Code

• setting up ultrasonic sensor and leds

//broadcast ultrasonic sensor telemetry to webpage hosted by ESP32
//by Rico Kanthatham, Skylabworkshop 2024

//pin connections
#define trigPin 5
#define echoPin 18
#define blueLed 2
#define greenLed 22
#define redLed 23

void setup(){

  //init Serial Monitor
  Serial.begin(9600);

  //pin mode specifications
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(blueLed, OUTPUT);
  pinMode(greenLed, OUTPUT);
  pinMode(redLed, OUTPUT);

}

void loop() {

  ultrasonicSense(); //run ultrasonic sensor function

}

void ultrasonicSense(){

  //send out ultrasonic pulse
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  //receive ultrasonic pulse
  duration_us = pulseIn(echoPin, HIGH);
  distance_cm = 0.017 * duration_us;

  //print ultrasonic telemetry
  Serial.print("distance: ");
  Serial.print(distance_cm);
  Serial.println(" cm");
}

• Asynchronous web server using the ESPAsynchWebServer library

• HTML to buld the web page will be store on the ESP32 Filesystem (SPIFFS)

• Must use pre-2.0 Arduino to utilize ESP32 SPIFF File Loader

• Tutorial to install SPIFFS for ESP32 here

• The ESP32 File Loader can be downloaded here

• When ESP File Loader is installed properly in the Arduino IDE, a new menu item will appear…

  

• To display charts…use the ichartsjs library