Mega clone resetting, 3D printer controller with RAMPS. Noise on the power?

Other Hardware General Electronics
1

I have a home made 3d printer, controlled via a Mega clone and a ramps board. Every now and then the Arduino itself will reset (once or twice a month), today it did it at the exact moment I switched on a wall wart (inductive, not switched mode) that was on the same group of 13A sockets as my printer's extension lead.

Power to the Mega board is supplied via the DC jack at 12V from an LM2596 module, stepped down from 24V that is used to power the printer hardware. The diode has been removed from the RAMPS board so the 24V supply does not feed into the Mega VIn. Another thing to note is I have removed the power mosfet from the Mega, so it cannot be powered via USB.

The fact that it reset at the same moment as I switched on the wall wart makes me suspicious that it was power noise, but as inelegant as a chain of 24V switched mode>12V step-down>5V linear regulator is, would any power noise not be filtered out?

Incidently, the RasPi that controls the printer did not reset and is plugged into to same 4way extension as the printer itself, although as this uses a different PSU it is not likely relevant.

Does anyone have any suggestions on what to look out for?

Thanks :slight_smile:

2

A ground loop would be one possibility. A block diagram of how everything connects might be useful.

3

Cheers Mark, I have attached a block diagram. The Arduino Mega does not receive power via the ramps board, but power is drawn from the Arduino to power an LCD graphical display with rotary encoder and SD reader.

The reason I removed the power control mosfet is that the arduino and display module combined draw more than 500mA @5V so did not want to overload any usb ports. Now, having explained this to you, I realise the onboard linear regulator must be dissipating at least 3.5W, probably closer to 5W when supplied with 12V. Is this likely too much for the small on board reg?

Cheers :slight_smile:

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IMG_20170813_0004.jpg
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4

Quick addition, it just reset again as I switched on the wall wart. I will look into creating some kind of filter.