12V Power Supply Intermittent Drops?

maraxen · January 27, 2021, 8:46pm

The 12V-rated LEDs on our eVOLVER will slightly dim intermittently for a breif period before brightness is restored. Looking at the fans with no vial in the sleeves, they also have the same intermittent periods where the spin uniformly appears to slow slightly. I think because of the fans, its definitely audible to some degree, and whenever I have noticed anything it’s always short-lived. It’s not a constant from what I can tell and I haven’t had any issues crop up yet, but I haven’t used a multimeter or another tool to troubleshoot. Is this normal for the 12V power supply and/or should I be concerned?

bgwong · January 28, 2021, 3:14pm

I am not sure what exactly is going on with the 12V LEDs, but for the stirring, the fans stop a bit during a serial input. The code is written this way to get better tunability on the fan speeds.

github.com

FYNCH-BIO/evolver-arduino/blob/master/SAMD21/RS485_STIR/RS485_STIR.ino#L104


  digitalWrite(12, LOW);
}
void update_values() {
  for (int i = 0; i < num_vials; i++) {
     Input[i] =  saved_inputs[i];
  }
}
void exec_stir()
{
  for (int i = 0; i < num_vials; i++) {
    if (Input[i]  != 0) {
      Tlc.set(LEFT_PWM,i, 0);
      //Serial.print("Code: " + String(in.output_array[i]) + " ");
    }
  }
  //Serial.println();
    while(Tlc.update());

If you look at the code, the execute stir command is counting, for each vial, how long to pulse the fan ON and OFF. Once a Serial command might come in, it might shut off for longer. It is not related to the 12V power supply itself.

Brandon

maraxen · January 28, 2021, 10:35pm

Thanks! I’ll look over our light Arduino code and see if that could be causing this. Good to know it’s probably not the power supply having issues

Topic		Replies	Views
12V Power Supply Connection to Motherboard Melted	10	407	February 12, 2021
Clarification on Current Power Supply Set-Up	3	330	January 14, 2021
Clarification on Power Supplies Hardware	6	423	March 23, 2022
Updated Motherboard Design Connection to RPi Hardware	5	394	March 8, 2022
Recommended RS485 Shield? Hardware	2	351	February 7, 2022

12V Power Supply Intermittent Drops?

Related Topics