85 lines
2 KiB
C++
85 lines
2 KiB
C++
// SPDX-FileCopyrightText: 2022 Limor Fried for Adafruit Industries
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//
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// SPDX-License-Identifier: MIT
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#include <Adafruit_I2CDevice.h> // requires https://github.com/adafruit/Adafruit_BusIO
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#include <Adafruit_SSD1306.h>
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#include <Fonts/FreeSans9pt7b.h>
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#define SR04_I2CADDR 0x57
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Adafruit_I2CDevice sonar_dev = Adafruit_I2CDevice(SR04_I2CADDR);
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// dont have a i2c device on bus faster than 100KHz, doesnt like it!
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Adafruit_SSD1306 display = Adafruit_SSD1306(128, 64, &Wire1); // connect to stemma qt - Wire1!
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void setup() {
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Serial.begin(115200);
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// SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
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if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3D)) {
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Serial.println(F("SSD1306 allocation failed"));
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for(;;); // Don't proceed, loop forever
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}
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display.display();
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delay(1000);
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//while (!Serial);
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// Clear the buffer.
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display.clearDisplay();
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display.display();
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display.setFont(&FreeSans9pt7b);
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display.setTextSize(1);
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display.setTextColor(SSD1306_WHITE);
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if (! sonar_dev.begin(&Wire)) {
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Serial.println("Could not find I2C sonar!");
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while (1);
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}
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Serial.println("Found RCWL I2C sonar!");
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}
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void loop() {
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uint32_t distance = ping_mm();
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display.clearDisplay();
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display.setCursor(0, 30);
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display.print("I2C Sonar");
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display.setCursor(0, 50);
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display.print("Ping: ");
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if (distance > 2) {
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display.print(distance, DEC); display.println(" mm");
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}
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Serial.print("Ping mm: "); Serial.println(distance);
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yield();
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display.display();
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delay(50);
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}
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uint32_t ping_mm()
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{
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uint32_t distance = 0;
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byte buffer[3];
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buffer[0] = 1;
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// write one byte then read 3 bytes
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if (! sonar_dev.write(buffer, 1)) {
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return 0;
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}
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delay(10); // wait for the ping echo
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if (! sonar_dev.read(buffer, 3)) {
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return 0;
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}
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distance = ((uint32_t)buffer[0] << 16) | ((uint32_t)buffer[1] << 8) | buffer[2];
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distance /= 1000;
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if ((distance <= 1) || (distance >= 4500)) { // reject readings too low and too high
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return 0;
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}
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return distance;
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}
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