DC Motor crashes Arduino Nano + DS18B20 Sensor + Max 7219 LCD

Hello,

I have the following problem: I am running an Arduino Nano together with a DS180B20 temperature sensor and a MAX7219 7-segment LCD over the same 12V DC power supply as a small 12V DC motor (motor rated at 0.7 A maximum). The DC motor is directly connected to the power supply. The 12V DC power supply has a maximum rated output of 3A.

After 30 seconds running fine the DC motor causes the DS180B20 temperature sensor and the MAX7219 7-segment LCD to crash / stop working correctly. I assume this is due to some motor noise. I did some research on the forum how to eliminate motor noise and tried the following:

  • 0.1 uF ceramic capacitor between + and - of the DC motor
  • 1000 uF buffer capacitor between + and - of the power supply

Sadly, this did not fix my aforementioned problem. Do you have suggestions how to fix this?

Thank you very much.

a MAX7219 7-segment LCD

?

Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.
Then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

What is the rating of your 12Vdc supply?

Thanks.. Tom.. :slight_smile:

TheMemberFormerlyKnownAsAWOL:
?

This is what I am speaking of:

Hi,
Thanks for the links, we still need a circuit diagram please.
OPs MAX7219 8 digit 7seg display.


Tom... :slight_smile:

TomGeorge:
Hi,
Welcome to the forum.

Please read the post at the start of any forum , entitled "How to use this Forum".
OR
http://forum.arduino.cc/index.php/topic,148850.0.html.
Then look down to item #7 about how to post your code.
It will be formatted in a scrolling window that makes it easier to read.

Can you please post a copy of your circuit, in CAD or a picture of a hand drawn circuit in jpg, png?

What is the rating of your 12Vdc supply?

Thanks.. Tom.. :slight_smile:

I hope this drawing helps:

Thank you very much for your valued help.

Hi,
Have you tried checking without the motor running.

If you are feeding 12V to the Nano Vin and using the 5V from the Nano to supply the LED display, you could be overloading the onboard 5V regulator.
It cannot dissipate much energy and the load of 8Digit 7 Seg LED display could probably be causing thermal overload and drop out.

Tom… :slight_smile:

Hi,
Thanks for the power diagram, having the motor at the powersupply terminals is the way to minimise any interference.

A complete diagram showing all the hardware you have connected to the Nano would help us understand your project.

A picture of a hand drawn circuit would do the trick.

Thanks.. Tom.. :slight_smile:

TomGeorge:
Hi,
Have you tried checking without the motor running.

If you are feeding 12V to the Nano Vin and using the 5V from the Nano to supply the LED display, you could be overloading the onboard 5V regulator.
It cannot dissipate much energy and the load of 8Digit 7 Seg LED display could probably be causing thermal overload and drop out.

Tom... :slight_smile:

Thank you very much for your fast reply.
Without the motor running I have no problems and the device functioned over several hours flawlessly. Therefore, I do not expect an overload of the 5v regulator of the Nano by the LCD Display. That, is why i assume that the DC motor is the culprit.
At the Nano I have only three devices connected: The DS180B20 thermometer, the Max7291 LCD and an SolidStateRelais.

Hi,
Good, then have you kept the motor wiring away from the controller and its peripherals.
Can you post a picture of your project so we can see your component layout?

the Max7291 LCD >>> the Max7291 LED

Thanks.. Tom.. :slight_smile:

This is a inside view of my selfmade 3d-printed enclosure. I admit that everything is quite packed in there.

The DC power supply is connected to the DC jack in the lower middle. The DC-Motor is connected to the DC jack on the left hand side. I now realize that I have ommited a maybe important fact: Between the motor and the PSU is a LM2596 step-down converter in order to throttle the motor. However it is set to 12V so no step-down occurs.

Can you clarify what you mean by 'crashes' ?
What exactly does that mean ?
Does that mean you get garbage ?
It's very hard to isolate LCDs from motor noise if both devices share the same supply. You can verify this easily
by simply removing the power connections for the DS18B20 and the LCD from the motor circuit and powering
them with a battery that shares a common GND with the motor circuit which will enable you to share data but
not power.

raschemmel:
Can you clarify what you mean by ‘crashes’ ?
What exactly does that mean ?
Does that mean you get garbage ?
It’s very hard to isolate LCDs from motor noise if both devices share the same supply. You can verify this easily
by simply removing the power connections for the DS18B20 and the LCD from the motor circuit and powering
them with a battery that shares a common GND with the motor circuit which will enable you to share data but
not power.

The LCD shows random numbers / scrambles and the DS180B20 stops reporting temperatures.

Garbage on LCDs is a universally common problem if the LCD shares a motor power supply.
I've had the same problem. I just used a different supply or battery and that eliminated the problem UNLESS
BOTH power supplies were plugged into the same AC BREAKER CIRCUIT, in which case the problem persisted.

Mareus:
The LCD shows random numbers / scrambles and the DS180B20 stops reporting temperatures.

Do you have an LCD?

TheMemberFormerlyKnownAsAWOL:
Do you have an LCD?

No, as established in several posts before, I do not have an LCD but a 7-segment LED Display driven by an Max7291 controller. I used the term “LCD” in order to more easily relate to what raschemmel asked.

@all
Is there a possiblity to filter out the motor noise by using - for example - a filter circuit?

Any ideas how to create a filter circuit to filter out the motor noise?

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