Arduino Mega Touchscreen Quiz Using Elegoo 2.8" TFT LCD Shield
by jamesmainmon in Circuits > Arduino
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Arduino Mega Touchscreen Quiz Using Elegoo 2.8" TFT LCD Shield
this is a project that combines portability, cleanliness, and Arduino with Elegoo's 2.8" ILI9341 tft lcd touchscreen shield for arduino.
Supplies
You Will need an Elegoo 2.8" TFT screen , a cable to connect to your computer, Arduino IDE, and an Arduino mega 2560 r3. that's it!
Connecting the Shield
You need to connect the pins of the touchscreen shield to The mega carefully, Making sure that you don't bend the pins. Connect the same pins as you would on an UNO R3. then move on to step 2.
Add the Code
you will need the following libraries:
1) Open Arduino IDE and connect the Arduino to your computer via USB.
2) Download the libraries via "download ZIP library" in sketch toolbar.
3) copy and the code below after removing the starting code.
4) Select your Arduino in the select board" portion.
5) Upload the code to the Arduino.
#include <Elegoo_GFX.h>
#include <Elegoo_TFTLCD.h>
#include <TouchScreen.h>
// --- Touchscreen pin definitions ---
#define YP A3
#define XM A2
#define YM 9
#define XP 8
// --- Touchscreen calibration values (adjust as needed) ---
#define TS_MINX 120
#define TS_MAXX 900
#define TS_MINY 70
#define TS_MAXY 920
#define MINPRESSURE 100
#define MAXPRESSURE 1000
TouchScreen ts = TouchScreen(XP, YP, XM, YM, 300);
// --- LCD control pins ---
#define LCD_CS A3
#define LCD_CD A2
#define LCD_WR A1
#define LCD_RD A0
#define LCD_RESET A4
Elegoo_TFTLCD tft(LCD_CS, LCD_CD, LCD_WR, LCD_RD, LCD_RESET);
// --- Colors ---
#define BLACK 0x0000
#define WHITE 0xFFFF
#define RED 0xF800
#define GREEN 0x07E0
#define BLUE 0x001F
#define YELLOW 0xFFE0
#define SCREEN_WIDTH 320
#define SCREEN_HEIGHT 240
// --- Question structure ---
struct Question {
const char* text;
const char* choices[4];
int correctIndex;
};
// --- Question bank ---
// this section is sorted as: {"question",{"answer 0", "answer 1", "answer 2", "answer 3"}, number for correct answer}
// feel free to customize this bank. the MEGA 2560 r3 can hold about 100 questions.
Question allQuestions[] = {
{"Who was the main guy in communism during c.r.?", {"mao", "sun yat sen", "deng xiapeng", "cheng kai shek"}, 0},
{"Incriminating poster used to attack people during the Cultural Revolution?", {"propaganda", "meanie sheet", "da zi bao", "mao poster"}, 2},
{"The carving up of China by European powers into spheres of influence was known as what?", {"Europeans giving to China", "Cutting the melon", "The Great Wall", "Unequal treaties"}, 1},
{"Why did China lose the Opium Wars?", {"Unmotivated army", "Depressed populace", "Technological isolationism", "Mao"}, 2},
};
const int numQuestions = sizeof(allQuestions) / sizeof(Question);
int questionOrder[numQuestions];
// --- Shuffle the questions ---
void shuffleQuestions() {
for (int i = 0; i < numQuestions; i++) {
questionOrder[i] = i;
}
for (int i = numQuestions - 1; i > 0; i--) {
int j = random(i + 1);
int temp = questionOrder[i];
questionOrder[i] = questionOrder[j];
questionOrder[j] = temp;
}
}
void shuffleChoices(Question &q) {
const char* originalChoices[4];
for (int i = 0; i < 4; i++) {
originalChoices[i] = q.choices[i];
}
int indices[] = {0, 1, 2, 3};
for (int i = 3; i > 0; i--) {
int j = random(i + 1);
int temp = indices[i];
indices[i] = indices[j];
indices[j] = temp;
}
int newCorrectIndex = -1;
for (int i = 0; i < 4; i++) {
q.choices[i] = originalChoices[indices[i]];
if (indices[i] == q.correctIndex) {
newCorrectIndex = i;
}
}
q.correctIndex = newCorrectIndex;
}
// --- Text wrapping ---
void printWrappedText(const char* text, int x, int y, int maxWidthChars, int lineHeight) {
tft.setCursor(x, y);
char tempText[256];
strcpy(tempText, text);
char* rest = tempText;
char* word;
String line = "";
while ((word = strtok_r(rest, " ", &rest))) {
if (line.length() + strlen(word) + (line.length() > 0 ? 1 : 0) > maxWidthChars) {
tft.print(line);
y += lineHeight;
tft.setCursor(x, y);
line = word;
line += " ";
} else {
line += word;
line += " ";
}
}
if (line.length() > 0) {
tft.print(line);
}
}
// --- Draw question and answers ---
void drawQuestion(Question &q) {
shuffleChoices(q);
tft.fillScreen(BLACK);
tft.setTextColor(WHITE);
tft.setTextSize(2);
printWrappedText(q.text, 10, 10, 30, 18);
for (int i = 0; i < 4; i++) {
int x = (i % 2) * (SCREEN_WIDTH / 2);
int y = 60 + (i / 2) * (SCREEN_HEIGHT - 60) / 2;
uint16_t color;
switch (i) {
case 0: color = RED; break;
case 1: color = BLUE; break;
case 2: color = GREEN; break;
case 3: color = YELLOW; break;
}
tft.fillRect(x, y, SCREEN_WIDTH / 2, (SCREEN_HEIGHT - 60) / 2, color);
tft.setTextColor(BLACK);
tft.setTextSize(2);
tft.setCursor(x + 5, y + 5);
tft.print((char)('A' + i));
tft.print(":");
printWrappedText(q.choices[i], x + 15, y + 25, 15, 15);
}
}
// --- Get which answer was touched ---
int getAnswerTouch() {
TSPoint p = ts.getPoint();
pinMode(XM, OUTPUT);
pinMode(YP, OUTPUT);
if (p.z < MINPRESSURE || p.z > MAXPRESSURE) {
return -1;
}
int x = map(p.y, TS_MINY, TS_MAXY, SCREEN_WIDTH, 0);
int y = map(p.x, TS_MINX, TS_MAXX, SCREEN_HEIGHT, 0);
for (int i = 0; i < 4; i++) {
int bx = (i % 2) * (SCREEN_WIDTH / 2);
int by = 60 + (i / 2) * (SCREEN_HEIGHT - 60) / 2;
if (x > bx && x < bx + (SCREEN_WIDTH / 2) && y > by && y < by + (SCREEN_HEIGHT - 60) / 2) {
return i;
}
}
return -1;
}
// --- Show feedback ---
void showResult(bool correct) {
tft.fillScreen(correct ? GREEN : RED);
tft.setTextColor(BLACK);
tft.setTextSize(3);
tft.setCursor(80, 100);
tft.print(correct ? "Correct!" : "Wrong!");
delay(1500);
Serial.print(correct ? "Correct!" : "Wrong!");
}
// --- Setup ---
void setup() {
Serial.begin(9600);
randomSeed(analogRead(0));
tft.reset();
tft.begin(0x9341);
tft.setRotation(1);
tft.fillScreen(BLACK);
shuffleQuestions();
}
// --- Main loop ---
void loop() {
static int currentQuestionIndex = 0;
if (currentQuestionIndex >= numQuestions) {
tft.fillScreen(BLACK);
tft.setTextColor(GREEN);
tft.setTextSize(4);
tft.setCursor(30, 100);
tft.print("Quiz Complete!");
Serial.println("Quiz complete");
while (true);
}
int qIndex = questionOrder[currentQuestionIndex];
Question q = allQuestions[qIndex];
drawQuestion(q);
int selected = -1;
while (selected == -1) {
selected = getAnswerTouch();
delay(200);
}
// Wait for user to lift finger
TSPoint p;
do {
p = ts.getPoint();
pinMode(XM, OUTPUT);
pinMode(YP, OUTPUT);
delay(50);
} while (p.z > MINPRESSURE && p.z < MAXPRESSURE);
bool correct = (selected == q.correctIndex);
showResult(correct);
currentQuestionIndex++;
}