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Topic: Detecting RFI from an Uno (Read 207 times) previous topic - next topic


Is there any practical way to detect the amount of RFI a Uno puts out?  Is there any simple device that can tell me how much "noise" (locally) I am emitting from an Uno?

Thank you


An "all wave" radio receiver will let you listen to the RFI, but cannot give you any actual numeric values. Use a wire antenna and move the wire around over the Uno.



There are a number of rtl-sdr spectrum analyzer projects available on the internet.  This gives one a visual display of the radio spectrum over some range.  This will be uncalibrated and the cheap rtl-sdr radios are prone to internally generated spurs, but it can give useful qualitative information.



Or you can use a high value (maybe 10MOhms or more)pull-up or pull-down resistor connected to one of the Analog pins and do some averaging with analogRead of that pin. The readings will fluctuate based on the local EMI


I wish you luck, you are taking on a major project. Try this link for some good information:
From the above link:
There  are  two  broad  categories  of  interference;  narrow band and broadband.

Narrow Band - this  would  include  continuous  wave (CW) or modulated CW signals. Examples might include clock harmonics from digital devices, co-channel transmissions,  adjacent-channel  transmissions,  intermodulation  products,  etc. On  a spectrum analyzer, this would appear to be narrow vertical lines or slightly wider modulated vertical bands associated with specific frequencies.

Broadband - this  would  primarily  include  switch-mode power supply harmonics, arcing in overhead power lines (power  line  noise),  wireless  digitally-modulated  systems (such  as  Wi-Fi  or  Bluetooth), or digital  television. On a spectrum analyzer, this would appear to be broad ranges of signals or an increase in the noise floor. Power line noise or switch-mode power supplies are the most common sources.
Good Luck & Have Fun!

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