ESP32-Pill Reaction Time Tester

Hello

This is a tutorial on how to make a reaction time tester using an ESP32S3-Pill. The basic idea is that we'll have a board with two buttons, one LED and one OLED display. You'll have to press one of the buttons to start a test than the LED will blink three times and it'll go dark. As soon as the LED lights up again you can press a the other button to measure your reaction time which will be displayed on OLED display.

• ESP32 S3 Pill (here)
• OLED 128x64 0.96 I2C (here)
• Button 2x (here)
• Resistor 3x (here)
• LED (here)
• USB-C (here)
• Wires (here)
• Bread Board (here)

Bread Board:

(Check the image to see how to connect things on bread board with ESP32)

In this example button on the left starts the game.

OLED -> ESP32 / Bread Board:

• SDA -> PIN 14
• SCK -> PIN 12
• VDD -> 5V / 3.3V(BB)
• GND -> GND (BB)

Than just connect your ESP32 to USB-C and we're all set and ready to move to next step.

We'll be using ArduinoIDE. But before we start writing a code let's set some things up.

Click on Tools->Board->Boards Manager. Than search for esp32 by Espressif and hit install.

Click on Tools->Board->esp32 and select ESP32S3 Dev Module

Click on Tools->Manage libraries and install Adafruit GFX Library and Adafruit SSD 1306

And now let's start coding.

(Everything marked with "//" is comment. That means it's not a code, but a text written to help you understand it better. Try to read it and see if you understand what's going on)

//imports libraries
#include <ctime>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>


#define LedPIN 5          //stes up LED pin
#define ButtonPIN 16      //sets up Button pin
#define RSTButtonPIN 17   //sets up Button to start a game pin


#define I2C_SDA 14        //sets up SDA pin
#define I2C_SCL 12        //sets up SCL(SCK) pin
#define SCREEN_WIDTH 128  //OLED display width, in pixels
#define SCREEN_HEIGHT 64  //OLED display height, in pixels


TwoWire I2C = TwoWire(0);


//sets up display
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &I2C, -1);


// this methode is called first and sets up everything
void setup() {
  //sets up serial console
  Serial.begin(9600);


  //sets up I2C and display
  I2C.begin(I2C_SDA, I2C_SCL);
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) 
  {
    Serial.println(F("SSD1306 allocation failed"));
    for(;;);
  }
  delay(2000);
  display.clearDisplay();
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.setCursor(0, 20);


  //sets up all the pins
  pinMode(LedPIN, OUTPUT);
  pinMode(ButtonPIN, INPUT);
  pinMode(RSTButtonPIN, INPUT);
}

//this methode is called as second and loops forever
void loop()
{


  //if RSTButton is pressed star the game
  if(digitalRead(RSTButtonPIN) == true)
  {
    //sets up RNG
    srand(time(NULL));
    //blinks LED three times
    for(int i = 1; i <= 3; i++)
    {
      digitalWrite(LedPIN, HIGH);
      delay(1000);
      digitalWrite(LedPIN, LOW);
      delay(1000);
    }


    //stops program for raandom time
    delay(((rand() % 18) + 3) * 1000);


    //lights up LED and starts counting time
    digitalWrite(LedPIN, HIGH);
    unsigned long pastTime = millis();


    //loops forever
    while(true)
    {
      //if button is pressed measure time 
      //write it on display and break of loop
      if(digitalRead(ButtonPIN) == HIGH)
      {
        unsigned long time = millis();
        display.clearDisplay();
        display.setCursor(0, 20);
        display.print(time - pastTime);
        display.println(" ms");
        display.display();
        break;
      }
    }


    //turns off LED 
    digitalWrite(LedPIN, LOW);
  }
}

Now just hit upload and you're done

Great Job :D