L298N: too Low Voltage on Out1 & Out2 pins

[ava18]

I am trying to give 35V DC on output of the L298N board, but as a result a get 3V DC.

On picture (Left to Right):

• DC to DC Voltage regulator powered by 12V PSU and gives 35V DC on output.
• L298N powered by 35V DC, controlled:

• by Green wire on ENA thru 5~ pin on Uno
• by Black wire on IN1 thru 7 pin on Uno
• by Blue wire on IN2 thru 8 pin on Uno

• Uno R3 powered USB and running code:

#define LED LED_BUILTIN

#define ENA 5
#define IN1 7
#define IN2 8

void setup() {
  pinMode(LED, OUTPUT);
  pinMode(ENA, OUTPUT);
  pinMode(IN1, OUTPUT);
  pinMode(IN2, OUTPUT);
  digitalWrite(IN1, LOW);
  digitalWrite(IN2, HIGH);
}

void loop() {
  analogWrite(ENA, 255);
  delay(100);
  digitalWrite(LED, HIGH);
  delay(100);
  digitalWrite(LED, LOW);
}

Could you help me to find is a mistake?

Thank you.

[void-basil]

It probably needs a ground connection between the L298 module and the Uno.

[ava18]

void-basil:
It probably needs a ground connection between the L298 module and the Uno.

Could you say please what pins should be connected to ground signal on L298 and Uno?

[MarkT]

And you need proper wiring for the high current paths - logic hook-up wires may only be
rated at 100mA or so (its very hard to know without cutting one in half and stripping the
end to see how thick the copper is - best to use higher current wires for the motor supply
wiring and motor wiring.

[ava18]

Wiring is important, I agree. But currently it is beta version of the controller. And the main target is to achieve 35V output on L298N module. And I cant find any mistakes in my scheme. I am inclined to believe that Motor Driver and/or Uno are damaged.

[groundFungus]

Connect the ground from the L298 to Arduino ground.

There are much better motor drivers available. The L298 is ancient and very inefficient technology. The driver outputs drop from 2 to over 4 volts of the motor supply voltage (depending on current).

Pololu has a good line of motor drivers. Choose a driver based on motor supply voltage and stall current.

[void-basil]

ava18:
But currently it is beta version of the controller.

Hardly; the L298 chip is decades old, and even the module you have has been around for ages.

And the main target is to achieve 35V output on L298N module.

Whatever you put into the L298 you will get between 2 and 4V less than that out as stated above, and that's a consequence of its technology. So you'll get say 31-33V or so out, from 35V in.

But first you need to connect the grounds.

And when talking of a module like yours, ie the 298 chip on a board with other stuff, you should refer to it by its module name/model, not as an L298 which means the chip itself. Not all modules are the same, even if the chips are, and its lucky that groundFungus found a connection diagram of the one you have although you didn't name it.

[JCA34F]

If you are powering the module with more than 12V, you should remove the jumper (behind the screw terminals) and connect 5V from the Arduino to the 5V screw terminal. Do NOT connect Arduino 5V with the jumper in place.
What is the motor's current requirement and the converter's rated current output?

[ava18]

you should refer to it by its module name/model

Sorry for that, my bad. The talk is about this Motor Driver and this DC to DC converter. By the way, I am using Not Original board, but it should be fully compatible.

the L298 chip is decades old, and even the module you have has been around for ages.

I would like to point that I need to solve a task with any possible device, it doesn't matter the age, manufacturer or the way it functions. Electronics is not my strongest side that why I ask you guys to help me.

What is the motor's current requirement and the converter's rated current output?

Actually, I don't need to control a Motor. Task is to fade in/out fairy lights depending on time and date (what is not a problem). The problem is that these fairy lights are using reverse polarity to control odd and even LEDs. I need to change voltage polarity every (let say) 10ms to fade simultaneously odd and even LEDs in voltage range from approximately 20V to 35V and back to 20V. As far as I understand Motor Driver should handle this task? That is why I chose this category for my post.

But first you need to connect the grounds.

Interesting thing: I connected my Motor Driver ground to digital pin 14 (GND on Uno R3) and voltage output of Motor driver fall from 3V down to 0V. Everything other is the same as in my first post.

Thank you.

[ava18]

If you are powering the module with more than 12V, you should remove the jumper (behind the screw terminals) and connect 5V from the Arduino to the 5V screw terminal.

Sorry, It was necessary to test it first. The output of Motor Driver is now as expected (35V). Thank you for pointing my mistake.

[Wawa]

ava18:
Actually, I don't need to control a Motor. Task is to fade in/out fairy lights depending on time and date...

We know, because this is already the third thread for that project.

[void-basil]

ava18:
I connected my Motor Driver ground to digital pin 14 (GND on Uno R3)

You obviously mean the ground pin next to pin 13, but fyi that's never known as digital pin 14. Digital pin 14 is actually analog pin A0 diagonally opposite.