تاچ‌پد لمسی با پرینت سه‌بعدی و برد ESP32

// DIY sensor touchpad
// Markus Opitz 2026
// instructables.com
#include <Arduino.h>
// measure ***********************
const int ADC_PIN = A0;
const float VCC = 3.3;
const float R_REF = 1000000.0; // 1 MOhm reference resistor
const int N_SAMPLES = 64;
//coordinates **************
float resMin = 2.0;
float resMax = 6.0;
float resLine;
float resValue;
int x, y;
float resX;
// OLED ******************
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64
#define OLED_ADDR 0x3D // I2C-address (mostly 0x3C)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);
float mapFloat(float x, float in_min, float in_max, float out_min, float out_max) { //for using float values in a map funktion
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
void setup() {
Serial.begin(115200);
delay(500);
resLine = (resMax-resMin)/7; // 7 lines --> a 9 lines on OLED display
Serial.println(resLine, 3); delay(2000);
pinMode(ADC_PIN, INPUT);
analogReadResolution(12);
analogSetPinAttenuation(ADC_PIN, ADC_11db); // großer Messbereich bis nahe 3.3 V
if (!display.begin(SSD1306_SWITCHCAPVCC, OLED_ADDR)) {
Serial.println(F("SSD1306 not found"));
for (;;);
}
display.clearDisplay();
display.setTextSize(2);
display.setTextColor(WHITE);
display.setCursor(30, 25);
display.println(F("ready"));
display.display();
delay(1000);
}
void loop() {
uint32_t sum = 0;
for (int i = 0; i < N_SAMPLES; i++) {
sum += analogReadMilliVolts(ADC_PIN);
delayMicroseconds(200);
}
float vOut = (sum / (float)N_SAMPLES) / 1000.0;
float rX;
if (vOut <= 0.001) {
rX = 0.0;
} else if (vOut >= VCC - 0.001) {
rX = INFINITY;
} else {
rX = R_REF * vOut / (VCC - vOut);
}
Serial.print("Vout = ");
Serial.print(vOut, 3);
Serial.print(" V, Rx = ");
resValue = rX / 1000000.0;
if (isinf(rX)) {
Serial.println("> Messbereich / sehr hochohmig");
}
else if (resValue > 75) Serial.println(" - ");
else {
Serial.print(resValue, 3);
Serial.print(" MOhm ");
checkXY();
Serial.print(x); Serial.print(" "); Serial.println(y);
displayDot();
}
delay(500);
}
void checkXY() {
if ((resValue > resMin) && (resValue < (resMin + resLine))) {
y=5;
//resX = resValue;
//x = mapFloat(resX, resMin,(resMin+ resLine) , 1, 128);
x = (int)mapFloat(resValue, resMin, (resMin+ resLine), 1, 126);
//Serial.println("line 1");
}
if ((resValue > resMin + resLine) && (resValue < (resMin + 2 * resLine))) {
y=14;
resX = resValue;
//x = mapFloat(resX, (resMin + 1*resLine),(resMin+ 2*resLine) , 128, 1);
x = (int)mapFloat(resValue, (resMin + 1*resLine), (resMin+ 2*resLine), 126, 1);
//Serial.println("line 2");
}
if ((resValue > resMin + 2 * resLine) && (resValue < (resMin + 3 * resLine))) {
y=23;
resX = resValue;
//x = mapFloat(resX, (resMin + 2*resLine),(resMin+ 3*resLine) , 1, 128);
x = (int)mapFloat(resValue, (resMin + 2*resLine), (resMin+ 3*resLine), 1, 126);
//Serial.println("line 3");
}
if ((resValue > resMin + 3 * resLine) && (resValue < (resMin + 4 * resLine))) {
y=32;
resX = resValue;
//x = mapFloat(resX, (resMin + 3*resLine),(resMin+ 4*resLine) , 128, 1);
x = (int)mapFloat(resValue, (resMin + 3*resLine), (resMin+ 4*resLine), 126, 1);
//Serial.println("line 4");
}
if ((resValue > resMin + 4 * resLine) && (resValue < (resMin + 5 * resLine))) {
y=41;
resX = resValue;
//x = mapFloat(resX, (resMin + 4*resLine),(resMin+ 5*resLine) , 1, 128);
x = (int)mapFloat(resValue, (resMin + 4*resLine), (resMin+ 5*resLine), 1, 126);
//Serial.println("line 5");
}
if ((resValue > resMin + 5 * resLine) && (resValue < (resMin + 6 * resLine))) {
y=50;
resX = resValue;
//x = mapFloat(resX, (resMin + 5*resLine),(resMin+ 6*resLine) , 128, 1);
x = (int)mapFloat(resValue, (resMin + 5*resLine), (resMin+ 6*resLine), 126, 1);
//Serial.println("line 6");
}
if ((resValue > resMin + 6 * resLine) && (resValue < (resMax))) {
y=59;
resX = resValue;
//x = mapFloat(resX, (resMin+6*resLine),(resMax) , 1, 128);
x = (int)mapFloat(resValue, (resMin + 6*resLine), resMax, 1, 126);
//Serial.println("line 7");
}
}
void displayDot() {
display.clearDisplay();
display.fillCircle(x, y, 2, SSD1306_WHITE);
display.display();
delay(10);
}