Arduino resets when solenoid shuts off

You may also want to use some ferrite beads on your power feed

Trying to find the root cause first.

Hi Mark

I will replace the 100uF. I will rather solder a socket for plugging different capacitor values. Here is my code..

// define pin for the relay output 
#define RELAY 4

//define pin for the PIR sensor input
#define PIR 8

//define pin for reading status of raspberry pi
#define RPi 9

void setup() {
  // put your setup code here, to run once:
  pinMode(RELAY, OUTPUT);
  pinMode(PIR, INPUT);
  pinMode(RPi, INPUT);
  digitalWrite(RELAY, LOW);
  digitalWrite(RELAY, LOW);  
  delay(1000);
}

void loop() {
  
  if(digitalRead(PIR) == HIGH){
    digitalWrite(RELAY, HIGH);   
    }   

}

Thanks

I presume the RPi detection aspects haven't yet been implemented ...

You will need to tie the RPi GND and the Arduino GND together if you intend to detect it's state.

Because the GPIO on the RPi is 3v3 the Arduino can handle it and it will be detected.

You can simply put the cap onto the pins of the relay shield in the meantime.

It will be enough to sort out the issue.

Mark

Hi Mark

Thanks.

At the moment, I just want to power up the RPi when PIR sensor is active. If this issue is resolved, I will read the state of the RPi so that I can switch-off the relay when the RPi completed shutdown. I got this working when the display is connected.

I got now 1F. I will replace the 100uF and see if the problem goes away. I hope I don't get electric shock with the 1F

Hello maranatha, can you use the arduino led (digital pin 13) to debug the problem? Turn on the led the same time you want to activate relay then click in the button that you replace by the PIR sensor and see what happen.

Hi Mark

Thank you!!!

I have to confess that I had been ignoring some basic principles.  I almost went to cry when the 1F didn't resolve the issue. Desperately, I just connected the grounds of the raspberry pi and the arduino...and it worked. I said desperately, because I had the GNDs of both Arduino and RPi connected when I started the project. It was working. But then, somewhere on the internet I read that connecting the GNDs of two separate circuits can be dangerous. So, I removed it. Removing that common GND didn't affect the operation until I decided to run the RPi headless. I removed the HDMI display and I start to have this ugly problem for more than a month. I should have tested removing the HDMI display in my original setup where both GNDs are connected.

I hope this fixes the problem permanently! I will just keep this 1F capacitor for decoupling. I have also soldered ferrite beads for extra protection.

I would be more than happy if somebody could explain me about the relevance of connecting the GNDs of both

Your diagram of your set up is incorrect. The most vital bit of information was missing - the input feed to the Arduino from the Rpi.

If you want to keep both boards electrically isolated you'll need to use an optocoupler or a relay set in in reverse to drive the Arduino input pin to it's own gnd.

You've got plenty of relays so it should be an issue.

I'd remove the capacitor and ferrite beads for the moment.

Removing that common GND didn't affect the operation until I decided to run the RPi headless

Are you using wireless or ethernet to connect ot the RPi.?

I am using WiFi. RPi-3 provides integrated WiFi.

Hi COMPACT

This is a preliminary test setup. I will have a pin feed from the RPi to the arduino for status check.

Hi COMPACT

This is a preliminary test setup. I will have a pin feed from the RPi to the arduino for status check.