Arduino EMF detector
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- เผยแพร่เมื่อ 14 พ.ค. 2009
- Use an Arduino microcontroller to sense invisible electromagnetic fields using wire, a resistor, and an LED.
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Aaron ALAI's EMF detector project is awesomely simple to make and fun to use. An upgraded version can be built using an LED bargraph for more 'meter-like' functionality.
original project can be found here -
www.aaronalai.com/emf-detector
additional info, and Arduino sketch -
makezine.com/video/arduino-emf...
audio/video by Collin Cunningham - วิทยาศาสตร์และเทคโนโลยี
![โอ้มายก๊อด! ไม่ถึงชั่วโมงหมดเป็นแสน 😅 [cc] แดนแพทตี้ SS2 | EP.42 |](http://i.ytimg.com/vi/OH2ShXfO6tA/mqdefault.jpg)
Where is this guy? I miss him. He had the best videos.
***** Worst switch ever. I feel like his videos on Make were way better than on adafruit.
Awesome project. Now add 2 or 3 more antenna's to help you triangulate the direction.
My Dad went hunting and he didn't come back yet. This will help during the night.
Extremely cool! I need to build one of these to play around with some day
Having learnt programming on a Synertek Sym-1 SBC in the '80s, I can assure anyone new to embedded programming that Arduino is a whole lot more fun and easier to program.
Also, look up Pachube (or Cosm)
Amazing !! Just made one!
Placed the Bar graph further away from the antenna ;)
Thanks for the circuit diagram and the Bar graph program.
cool project! as an electrical technician i'm certainly gonna have to make one of these, with a bit of tweaking it would be an excellent transformer tester.
nice project u made with the led bar graph thing.
Kinda cool with the bar graph. You can buy a similar device at any Home depot or Lowes in the electrical dept. Electrcians call it a "tick tracer". It does not have a bar graph though. It just makes a chirping sound when it gets near an alternating EM field.
I love this setup, however I was having problems with the sketch. I finally discovered the problem "index" was being used in the code, however an upgrade to the ARDUINO programming software declared index as a reserved word. I used the replace and find option on the ARDUINO software to change the name 'index' to 'dindex' and it all came together. Of course you can choose any non reserved word and the problems end! I hope this will solve problems for anyone trying to use this old code to build one of these. I realize this is a very old video but it is still relevant to today's needs.
very neat Collin!!!
Nice idea yours.
Try add some sort of amplifier, with a really high sensivity like a FET, and then we will be talking about detection!
And why not give some sound feedback to it? It may be the first digital theremin ever made
What 1980's 8-bit video game soundtrack is this? Loving it! Subtle,very subtle. :)
Done! Works perfectly:) thanks again Colin
@MrEinstain i kept it clear because it looks cool looking inside
Totally did this, fun and simple project.
Wire moving all around, would be interested to see it more solid.
I built one of those mosfet-enabled electrostatic polarity detectors. How does this do with static fields?
I noticed that my "antenna probe" was actually being pulled towards the static charge, and using it near my Wimshurst machine once, it attracted a spark and fried the mosfet. Good thing I ordered 50 of them. ;)
Could you use 3 "wire probes" (one pointing 45° to the left, one pointing straight ahead, one pointing 54° to the right) to get 3 readings, to have a better understanding of the spatial layout of the EMF? And could you use an LCD to display the obtained data as bars *and* numbers?
Also each LED is connecting to its own output pin so each LED can be controlled individually, if you tried what you are suggesting every time one pin goes high all of the LED would see the voltage.
Very interesting project
Could you tell me the lenght of the wire probe ?
Your sketch link no longer works. Can I please get a link to the sketch, I'm trying to figure out how the multi-led works. Thanks.
@6x6F its an arduino shield.the sheind costs nothing but spare parts.auduinos can do almost anything with programing.
Very nice. I'm going to try this. Thanks for showing us.
Very interesting project. What make the wire so sensitive? Is it because of the pull-down resistor or because the arduino internally amplify signal received on the input pin ? Is it sensible enough to detect wires behind the walls ?
Its the electromagnetic induction that creates a very small voltage across the resistor. And arduino's analog pin reads that voltage and shows the LED bar accordingly.
And Arduino Uno has a 10-bit ADC, so it can't measure voltage less than 4.8mV. You can try detecting wires behind walls. If the current through the wire is high enough, you might be able to detect that.
Cont'd: So the M.F is oscillating at the frequency of the AC current. Also, even if it were DC, the guy is still moving around as he tests possible sources, which creates changes in magnetic flux even if the field itself is constant (again, Faraday's law), which in turn induces an emf in the probe. An electric field will also induce a current in this probe since the charges in the probe are free to move (unlike on a capacitor for example) and since it'll move charges, it'll induce a M.F too.
@TheMagicalTouch no, when an EMP goes off it gives off EMP waves, and if an EMP went off aroud this toy, the leds would get so hot, they would melt the pcb.an EMP is a pulse of an EMF.
They would share the same current so brightness would be affected the more LED's turned on at the same time (unless the sketch is updated so that only one LED is turned on at a time).
Using one resister would mean all LED's share the same current limitation provided by that one resister.
As most insulation doesn't block EM waves, that wire doesn't need to be stripped to be an antenna, it's actually safer to have it insulated...
@gandulfo77 Since the basic energy type is electromagnetic, and there is no magnetic energy other than electromagnetic, then this is in fact an Electromagnetic field detector. It might detect only some electromagnetic fields, but the uploaded didn't spoke about it's sensitivity. Of course if the field is too low it will not detect it. But it's still an electromagnetic field detector. All electromagnetic energy is the same, magnets, wires or electromagnets.
Collin is awesome!
with a IR-sensitive phototransistor, you could probably also make a quite useful remote tester out of this :)
Can I use it to detect ghosts?
+Amalokch GHOSTFACERS!!
We face the ghosts when the others will not.
+R haha supernatural fandom YES!!
Amalokch if it generates emf it's possible
paranormal activity emits EMF's so chances are it will work
Congratulations. Nice movie, i love that project :P
Great work.......... loved it
You could, but with a current limit applied to the total of all the LED elements, as more light up (draw current), the current available to each element decreases, meaning more lit up = less brightness each
We can read frequency of these waves, using LCD, can you upload a video of the circuit? It'd be really kind of you.
Thank you!!
What is the significance of the 3.3 MOHM resistor? does it make the antenna more or less sensitive as the resistance value changes?
@gandulfo77 well, yeah, alternating magnetic fields, would generate some flow of electrons in the wire. makes sense to me.
you uploaded this video the day after my birthday
neat, i would like to know your results from different antenas
I own dozens of K2 and several Gause Meter.
The answer is maybe, but its not calibrated. Both K2 and Gauss Meter used a pickup coil & amplifier and some Low frequency filtering.
The only filtering this has is the input capacitance of the MCU's IO lines, which is a good amount seeing that they are FET's (hence almost no loading and needing that 2.2Mohm resister to drive it back to ground).
I wanna ask something. Why did you use a screw terminal? And which type of screw terminal did you use?
praps by using a shielded bit of cable for the probe and then space that block a bit and cover in anti static stuff. would be the budget way to go
We do it buffer-less all the time...its not like your driving an inductive load or heavy resistive load.
Atmega can easy do 20ma (possibly 40)...but LEDs would light up as easy as 1mA depending on resister selection (if you are really concerned).
the Atmega used in this project is probably
could you use a wire coil instead of an antenna? After all, you are detecting the magnetic flux, which induces a current in the wire.
Could u please text a list of all the equipment used for the Arduino EMF bar graph project?
Nice!
Do you have any idea what EMF strenght each level represents?
What is the best arduino for a beginner (no experience with controller boards but some with circuits slightly more involved than a basic light circuit) to get?
i wonder would you get a better signal from a coiled antenna instead of a single wire?
ye have inspired me to do more arduino prjects, good sir!
That's some boss tool, I wonder how much that will cost if you sold it.They have volt detectors, but the good ones are like $30.00, and you can make it into a box, so it would be worth less from how bulky, but its so cool
what kind of arduino should we use to get it? How can i explain it to radio shack to buy it? Any model, serial number, or else..?
@gandulfo77 yea, its probably EMF, depending on the use. if you mean for "ghost hunting" then this is not the right thing to be using.
it's a programmable processor circuit board that allows for multiple functions and uses.
Should this only detect AC current (or rapidly pulsing DC) , if i understand the design correctly that's all it should pick up if not what am i missing. (also this would explain the very low reading on the laptop)
@makemagazine
Can you please update the link in the video description ?
It's not working anymore. (additional info, and Arduino sketch -)
Awesome, really need to get a couple of arduinos...
I like it!
Where can I find the code for the LED bar graph version?
How can you hook a speaker to it so you can hear the waves? and also what about a LCD screen good Idea or no?
what type of proto shield is that and where can you buy one, also the wire holder for the probe, where to buy? thank you for your help.
bernardo cervantes eBay for both...just search Arduino proto and pc power
Will the sensor react to a turned off car/vehicle? If so, how well?
Thank you in advance!
That is pretty cool. Also, I feel the need to mention that you kind of look like David Cross, from scary movie 2.
I don't normally favourite video's but this one is worth it.
im looking to buy a arduino and i want o make some of these cool projects but i dont wnt to spend alot .which arduino should i buy
Hello;
I built an Arduino EMF Detector but i have a problem. The values on the EMF screen are unitless. I see huge numbers like 500.000 , 200.000, 300.000 when an electromagnetic field occurs. Also there is always a constant value just about 50.30, 49.32, etc.
1)I want to see the values as frequency. How can i convert it to the frequency? Is it possible? If it is, could you help me?
2)I use a copper cable as antenna. What is the reason of constant value? Is it because of antenna or because of crircle?
Thank you...
Electromagnetic Projects
Those huge numbers are ADC values. You have to convert them to analog voltage. For example: 500*(5/1023)= 2.44V
And the constant value is most probably caused by random noises, which may come from radio waves, or even from your home AC power supply 😉
thank you so much..:)
@evilking2006: You can find them for about 2 to 4 dollars in any radioshack.
An Uno or Leonardo. The Leonardo is the latest and slightly cheaper but you need a USB cable with a micro plug while for the Uno you need a B plug like a printer cable which you might already have. Also the Uno micro-contoler is replaceable if you damage it.
I don't know. Easiest test is to build an RF quite box and test in there. I bet you'll see the level drop to zero. But I doubt you're getting internal noise.
My DMM can sense RF current in the air too. I've noticed if I put it in voltage sense mode I get a wild display of numbers.
how many bars would oyu get if you would place it in a gaming rig running at full load?
thats really cool. Could you help me with how to program it?
do all Arduino's come with a proto shield under them and if not were can i get one and how do you install it
DO you any hall effect sensor that can measure higher values of tesla over 1 using arduino
once u uploaded the code on the Arduino, can u disconect it from the USB and still work ? what about a power supply ?
I think the Ghost hunters should make a lot of these and leave them along the paths of residual hauntings
Hello. This device can detect gold and silver frecuencys ?
Very nice!
Maybe add a second probe and set of LED's. Then add a number screen to display the difference between them. The device could be used to guesstimate current strength of two areas. Helpful when looking for shorts or other problems.
Very cool!
Would this work with a 3.9M ohm resistor?
Esse Video é POG.!
Can you helm me?
I try make that project whit arduino nano use that code ,it not work,bargraph high all of them,
What the difference of arduino uno and arduino nano,on code side ?
Arduino nano use same ship on arduino uno
EMF goes through wire coating. So what is the purpose of stripping the wire end?
Dear Collin, I wanted to ask would this work as a metal detector? If not, could you recommend an Arduino circuit that would work. Thank, Merry Christmas.
I really doesn't know much about Arduino programming, only web programming.
My question is, as a programmer, would it be possible to program the LED bars, to show bars according to how much current or whatever type of electricity is detected with the probe wire ?
Which is the best material to be used as the antenna?
Kipkay only does weekend projects, and he already posted one this weekend.
what kind of baterry are you using to power the arduino
to measure continous fields you can use a hall effect sensor
what is the biggest potential difference that can develop by using the wire?
@gandulfo77 these changing electric field produce a magnetic field... as per maxwells equations....
well then, if it detects electromagnetic fields, can you modify it to detect an electrical charge?(be it negative or positive)
Brilliant!
would lead shielding stop this and if so, how thick?
I havent got a 33ohm resister will other resisters work though?
would coiling the wire help or hurt?
Why not using torus shaped solenoid as the receiver/sensor?
you can also use a AM radio on band 3
Are you referring to merely a meter such as the one in this video? If so, that is only indicating that there is a field with the intensity increasing as it moves closer to the source. This is the same exact thing as a voltage sensor for $12.97 at Home Depot. Go check it out.
If you need a more accurate measurement such as direction of magnetic field and specific intensity then you are talking about a different animal with the Gauss.
@matthewtchernev123 Not really that hard. There is just a problem with switch. I reccomend using magnetic switch and magnetic bracelet mounted on bottle. That way it'll be 100% waterproof.
Ghost Busters own-ages, Add those little antenna. Could probably find the toy that was made to look like it package this into that and you'd have a real EMF machine.