Keyestudio ESP32 Manual page 151

float checkdistance() {
// preserve a short low level to ensure a clear high pulse:
digitalWrite(TrigPin, LOW);
delayMicroseconds(2);
// Trigger the sensor by a high pulse of 10um or longer
digitalWrite(TrigPin, HIGH);
delayMicroseconds(10);
digitalWrite(TrigPin, LOW);
// Read the signal from the sensor: a high level pulse
//Duration is detected from the point sending "ping" command to the time
echo signal (unit: um).
float
distance = pulseIn(EchoPin, HIGH)
delay(10);
return distance;
}
LedControl lc = LedControl(DIN, CLK, CS, 4);
byte data_val[4][8]
{ 0x00, 0x00, 0x00, 0x01, 0x01, 0x00, 0x00,
{ 0x00, 0x00, 0x04, 0x05, 0x05, 0x04, 0x00,
{ 0x00, 0x10, 0x14, 0x15, 0x15, 0x14, 0x10,
{ 0x40, 0x50, 0x54, 0x55, 0x55, 0x54, 0x50,
};
void setup() {
lc.shutdown(0, false);
lc.setIntensity(0, 8);
lc.clearDisplay(0);
pinMode(TrigPin, OUTPUT);
pinMode(EchoPin, INPUT);
Serial.begin(9600);
}
void loop() {
distance = checkdistance();
Serial.println(distance);
if (distance < 15) {
temp = 0;
else if
} (distance
temp = 1;
else if
} (distance
temp = 2;
else if
} (distance
temp = 3;
}
for (int i = 0; i
lc.setRow(0, i, data_val[temp][i]);
}
}
8.5. Arduino Project
//Acquire distance
= {
//MAX72XX is in power-saving mode at startup
//Set the brightness to its maximum value
//Clear display
//Set Trig pin to output
//Set Echo pin to input
< 30 && distance >
< 40 && distance >
> 50) {
< 8; i++) {
/ 58.00; //Convert into distance
0x00 },
0x00 },
0x00 },
0x40 },
15) {
30) {
ESP32 Starter Kit
(continued from previous page)
receiving␣
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