Send signal from Arduino-UNO to ESP32-CAM when Ultrasonic has less than desired distance

Other Hardware Sensors
1

I have an Ultrasonic sensor connected with my Arduino-UNO for calculating distance. I also have an ESP32-CAM, that when I press the RESET button, it captures a picture and saves it to an SDCard. What I am trying to do, is when the distance from Ultrasonic is less than 15cm, the Arduino will trigger the ESP32-CAM to take a picture and save it to the SDCard.

I have read somewhere, that in order to trigger the RESET button, I need to trigger the GPIO 0 and GND of the ESP32-CAM together. In my case, these are connected to pins 12 & 13 of the Arduino. So the code in Arduino is this:

#include <Ultrasonic.h>
Ultrasonic ultrasonic(10, 9);
int distance;

#define WAIT_TIME 5000

void setup() {
  Serial.begin(9600);
  pinMode(12,OUTPUT);
  pinMode(13,OUTPUT);
}

void loop() {
  // Pass INC as a parameter to get the distance in inches
  distance = ultrasonic.read();

  if (distance <= 15) {
    Serial.print("You are gonna crash! Distance in CM: ");
    Serial.println(distance);

    // Trigger GPIO0 and GND.
    digitalWrite(12, HIGH);
    digitalWrite(13, HIGH);
    delay(WAIT_TIME);
  } else {
    Serial.print("Distance in CM: ");
    Serial.println(distance);
  }
  delay(300);
}

But nothing works when Ultrasonic is triggered. It just delays for the WAIT_TIME and then it continues again calculating the distance. Here is the Serial Monitor:
image

Please ask for any other explanation you may need. Thanks in advance!

P.S. I am total newbie in stuff like that, so please try to explain to me with simple words :slight_smile:

2

Unless you have other things going on on your Arduino, and thus need it, I'm thinking it could all be done on the ESP32-CAM as boards can have sensors attached. https://esp32io.com/tutorials/esp32-ultrasonic-sensor

1 Like
3

Thanks for the link. It is really helpful, but I need to use Arduino because it is an assignment. I also use ESP32-Cam and not any ESP32.

4

Did a search on how to reboot/reset ESP32-CAM without pressing the button using DuckDuckGo "soft reset ESP32", and I think you have the wrong method. As it's an assignment you should be able to use this to help.

5

Can you paste the link with the correct "soft reset"?

6

Just google the words: soft reset ESP32
The 1st hit should be good.

7

I see that I must use ESP.restart(), but I can not use this in the code inside Arduino. My problem is ESP32-Cam to read distance from ultrasonic, through Arduino.

8

Looking at your ESP program, after it does the photo it puts the ESP32 to sleep with
esp_deep_sleep_start(); and the reset button is used to restart the script.

There are otherways to restart the ESP32 as defined in In-Depth: ESP32 Deep Sleep & Wakeup Sources | Timer, Touch & External for your case probably using ext0 External Wake-up Source and sending 1 high signal from Arduino to defined pin ext0 on ESP32.

10

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