Question SH1106 artifacting with arduino

shanedude02

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Mar 12, 2013
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Hi Guys,

Apologies if it's in the wrong section, this is the closest one I could think of.

Basically, i've got a really weird issue with an arduino, a map sensor and sh1106 display.
I've got a buck convertor set to 4.996v according to my multimeter feeding rhe arduino, screen and map sensor.

If I power it via USB, it seems fine.


If I power it through the buck convertor, the SH1106 artifacts like crazy.


I've tried, running power through the arduino using the 3v3 and 5v pins. Also directly from the buck convertor.

I've got no more ideas, wanted to see if anyone had any suggestions.
 

OldSurferDude

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May 18, 2019
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With what are you powering the buck converter? Can it provide sufficient current? You can power the Nano via the Vin pin (6-20V), though a buck converter may be more efficient.

Are you running the output of the buck converter to Vin or +5V? (Vin is before the onboard regulator and +5V is after). The latter is what you should be doing if you're trying to minimize power usage.

You may be getting high frequency noise. Try an electrolytic capacitor on the out put of the buck converter.

An oscilloscope would be handy. (as an example but no recommendation on Amazon)

A sort of related note: with power applied externally, you not using the USB and therefore you can use RX and TX with a serial adapter to help debug your project.

Good luck

OSD
 
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shanedude02

Distinguished
Mar 12, 2013
59
0
18,530
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With what are you powering the buck converter? Can it provide sufficient current? You can power the Nano via the Vin pin (6-20V), though a buck converter may be more efficient.

Are you running the output of the buck converter to Vin or +5V? (Vin is before the onboard regulator and +5V is after). The latter is what you should be doing if you're trying to minimize power usage.

You may be getting high frequency noise. Try an electrolytic capacitor on the out put of the buck converter.

An oscilloscope would be handy. (as an example but no recommendation on Amazon)

A sort of related note: with power applied externally, you not using the USB and therefore you can use RX and TX with a serial adapter to help debug your project.

Good luck

OSD
I think it was just electrical noise...
The power supply I was using is a cheap af 12v adapter. I hooked up a barrel plug to a cig lighter plug, powered it from the car no issues at all, ultimately that's where I'll be using it anyway.

I don't know why but electrical noise did not pop into mind at all last night... I'm powering it through the 5V pin rather than the Vin pin, purely because when I was soldering the traces on the back of the perf board, I did not think things through haha. Don't do stuff tired kids...

I've got a little DSO138 unit, haven't had a chance to test for noise yet, but considering it works fine over an alternator powered socket, I'd say that adapter I was using for power is a bit too noisy.

Thank you!
 

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