If the ECG is way more sensitive, isn’t that just a guarantee that this arduino thing will never be able to detect all the sources of potential interference?

Every time I see something like this I want to connect it to some inertial sensors (or now something like the Kinect’s depth camera) and map the relative location of all the sources in the room. Build up a 3D model of the space with all the sources and field strengths automatically modeled.

great idea!

I’ve run into a similar problem with what turned out to be one defective “energy saving” CFL nuking my wireless and 3G.
Seems that these things can totally wipe out phone signals, radio, 3G, wifi AND cause even laptop touch pads to malfunction at close range if the manufacturers cheaped out and used a wire link in place of the suppression components.

Another particularly wideband source of interference is those cheap 2.4GHz video sender/camera b0xen, normally sold for rebroadcasting DTV signals to save having multiple digiboxes.

this device should be in every tech’s toolbox, as it can save a lot of time in the long run.

@macw this might work.
What about using some of the xtal modules from old PC graphics cards and motherboards, some high end ones use them even now as they have lower phase noise than the onboard oscillators.
Add 1″ ferrite wirewound 1/4 wave antenna and it should be detectable from a few feet or so with a strong directional field.

#include “$0.01999992.FDIV”

@macw I’m also sick of this kind of retarded comment. Don’t just say the first thing that comes into your head.

The guy is creative hacker, but the only problem here is, that doesn’t make one a “qualified” RF EMI engineer.

I agree with @octel. Same kind of device used by these bogus “ghost hunters”, who have ZERO clue of what the hell they’re doing with any piece of equipment. I’ve watched these lame shows on sy-fy of these “researchers” claiming “look ! the EMF reading went up here!” (meanwhile never mind the fact that the damn HVAC or refrigerators are plugged in and running on thermostats).

You want to track down EMI ? How about doing it the right way, taking ‘baseline’ reference measurements ? ECG’s are designed to detect voltage differentials !

60 hz artifacts ? hmmm…. could it be ? how about checking for adequate grounding !

@macw:

Inertial mapping’s a rather non-trivial methodology absent high dollar, often totally closed source hardware&software. If you mean mapping as in a locational reference depiction? The idea of a Kinect may have potential. The devil’s half in the interfacing, and half in the data output method. My first take- a 3D monitor of some sort that your graphics would place a “Blip” upon where whatever you were wanting to denote was at a signal peak.

On second look? Just rolling a 3D camera while a human sweeps the room with whatever EMI sensor they have that can be “seen” by the camera might be “Good Enough” to capture data for fixing the issue. That’s if the human operator was still unable to find the EMI source.

I’ve found many weirds by using an old Zenith “Royal 500″ AM BCB radio. The internal ferrite antennas of some similar radios often has impressive sharp nulls.

@octel:

CFL’s are an exasperatingly random Crud Generator indeed. With the even more DANGEROUS fire risk of them being misplaced into dimmer/photocontrol switched sockets. The dimmer/photocontrol devices and fan speed controls also can be nasty RFI/EMI headache inducers. Tied only perhaps by a new wave of SMPS “Wall-Warts” that radiate in several SW bands.

If you go to the link where the code is posted you will find the “if” and “else if” tests in the main loop are the identical tests. Coding is not his strong point but he seems to have gotten it to work. I like it!

@AndyC & Todd Harrison: When I posted it up, I added comments on all the lines. I accidentally deleted that line and typed it incorrectly, without thinking. It is corrected now.

@j sNo DO-178B programming methods here. This is about as far from a certified medical device as an electrical outlet tester. It is not intended for use anywhere near patients. It is an electronics troubleshooting tool and not a calibrated instrument. If it fails, there are no risks.

On a side note, you should see how big of a field a Christmas tree presents. It’s a gigantic air-core coil inductor.

im not sure its EMF but just electromagnetic radiation

i think you need a receiver coil to make an EMF detector

Seems to me that a hound of a Fox and Hound set with 3 inches of wire and a better speaker attached, would make just as effective a probe. The type of sounds picked up are a good clue as to noise type, hum vs buzz. Only then the ultrasonics of switchers won’t be heard. The old LW band on a radio is good then. These hounds are baseband noise sensitive not AM band or higher, like a radio. Another case of arduino not needed. Don’t they make noise? Ghost hunters should work for the power company interference department, and get a Ham license.

@johno The antenna is not grounded. That’s what makes detection of electromagnetic fields possible. Because of this, it can be prone to ionization, or static buildup, which will make the antenna more sensitive to changes in the environment. Touching the antenna removes this buildup. It could be that you just have alot of unshielded devices or motors running.

There are several things you can do to decrease the sensitivity, first, change the frequency to 60 and watch your meter oscillate to be sure it is actually picking up 60 hz. Then, to decrease, or even increase sensitivity, add or remove from the lines:
incrementLED();

Or, alternately, add an additional:
decrementLED();

You could even get creative and add a loop which will change the sensitivity with a read input, a counter, and an if-then statement.

Hmph! using a [unshielded]clocked micro that RF-wise looks like a Fourier spectrum generator -to detect and qualify spurious RF…I choose an AM radio over this.