Questions tagged [interference]

For questions about electromagnetic interference (EMI); see also the [emc] tag.

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2answers
47 views

Terminating an audio line-in signal when source is disconnected

I've been trying to DIY a home audio setup. We have a pair of speakers in the ceiling of an upper floor (previously installed), and a new TV on the same floor. We wanted the sound of the TV to come ...
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1answer
34 views

Interference suppression coils for 9V DC adapter for audio equipment

I am about to add voltage regulation to an unregulated 230V AC to 9V 150mA DC adapter, by adding an L7809 voltage regulator and ceramic 0.33µF and 0.1µF capacitors. I want to use this adapter to power ...
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0answers
75 views

DC motor influences output voltages of power supply

I have a 12V compressor running on an old 350W computer power supply. This PSU also supplies a 5V microcontroller (Arduino Nano) and a 5V servo (SG90.) Whenever I start the compressor the servos swing ...
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1answer
42 views

How to reduce RFID interference

I am using a MFRC522 RFID reader I have read that it's antenna when in close proximity with metals then interference could be generated. What should be the distance between the antenna and the metal ...
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0answers
24 views

PH 4502 electrical interference EMI when in aquarium

I'm trying to get a regular ph reading in an aquarium. The sensor works well when the probe is in a small quantity of water(i.e. a glass) but has large variations in larger water quantities (i.e. ...
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1answer
34 views

Crosstalk between transmission lines

I was reading these slides about crosstalk between transmission lines. At page 6 there is this circuital model to describe the effect of mutual coupling between these two lines: My doubt is: why \$I_{...
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2answers
41 views

Esp8266 noisy input when wires go through power supply

I had made a circuit for led strip using esp12e. I had also attached two button to change between colors on the strip. To make it compact I inserted the circuit board inside the casing of 12v supply. ...
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0answers
28 views

Forward and Backward Crosstalk

I have some basic questions about crosstalk. My reference for this question is this website. This website introduces crosstalk in this way: Crosstalk is the unwanted coupling of energy between two or ...
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1answer
69 views

Controlling a Brushed Motor with DC Voltage to Avoid EMI (no speed control needed)

I have a fairly simple project coming up. My task is to design a system which powers and controls a Pan and Tilt positioner for a camera. It has some weird and unavoidable requirements/constraints: ...
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5answers
1k views

What are some quick, cheap hacks for determining the source of EMI in my house?

TL;DR - Without dumping a bunch of money, is there a quick MacGuyver-y way to help diagnose what's causing the EMI in my house? Longer - I have the curse that I'm a little too technical to be helped ...
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2answers
63 views

How can I create signal interference in a circuit? [closed]

I understand that this is counter intuitive but, as an experiment I want to create interference in a circuit. I want to expose an AC sinusoidal signal to a second sinusoidal signal. This will cause ...
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2answers
112 views

Why don’t radio waves interfere with each other like other waves? [closed]

I know this question has been asked before, but I still don’t completely understand. I understand that different stations are given different frequencies, but waves are able to interfere with each ...
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1answer
40 views

Arduino relay module interferece on signal pin (230VAC moror load)

I'm trying to switch a small 230V AC motor using an Arduino Uno, but I'm having same problems due to interference on the relay (so the Arduino itself is not a problem). Sometimes the module create ...
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1answer
37 views

WiFi Near Far Interference?

I have several ESPWROOM32 based modules that connect to a far away access point with an RSSI of -70 (it's about 50 feet away through several walls) and a close by access point with an RSSI of -30 (...
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2answers
109 views

Would twisting 3 wires together be as effective (or close) to a twisted pair?

Would twisting 3 wires together like a twisted pair would be as effective as an ordinary twisted pair? Or at least a definite improvement to not twisting them at all? simulate this circuit – ...
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2answers
90 views

If antennae work best at full, half or quarter wavelengths, why don't received signals at 1, 1/2 and 1/4 wavelengths interfere with each other?

How does a simple radio receiver-antenna differentiate between incoming wavelengths that are the same wavelength as the antenna, one-half and one-quarter? Or would I just hear static unless I have a ...
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0answers
36 views

Separating mains power from data lines

I'm an electronics hobbyist who's learning from wiring stuff together and searching the internet if something doesn't work. Hence my electronics knowledge is very patchy. I recently found out that ...
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1answer
21 views

Measure antenna S11 next to another source

I have a dipole antenna designed to work on ~800MHz and 2.44GHz frequency, and a miniVNA Tiny USB device that I can use to measure return loss of the antenna. I connect the antenna directly to the DUT ...
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1answer
37 views

Mesh Wire opening size for emi filter at frequency of 30Mhz

I want to use a mesh wire and I wanted to know how do I calculate an opening size of a mesh wire that can filter 30Mhz frequency. Your help is appreciated.
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27 views

ADVICES required PCB Design for domotic system using Odroid + STM32F103C + Different devices

I'm designing a PCB to connect all the devices I use for a domotic system together. I have a few general questions about it and I would like to hear some recommendations to improve it as I haven't ...
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1answer
52 views

How to eliminate electromagnetic interference when counting pulses using a micro controller?

I have written a pulse counter program for ESP32 micro-controller, the counter counts the pulses correctly when there is no EMI interference but as I turn on the small AC drill machine the counter ...
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1answer
50 views

Power interference when turning on speakers, causing monitor to go black

I have a small 2.1 external speaker system that I use with my laptop. I also have an external monitor that I use with the same laptop. Almost every time I turn on or off the speakers, the external ...
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2answers
70 views

How can picked up FM noise be demodulated?

I have a set of cheap computer speakers, which happens to use a TDA2822M. Its circuit is almost identical to the example circuit from TDA2822M's datasheet. It's USB powered and has no shielding. I ...
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0answers
44 views

Isolated step-down module for powering a Raspberry Pi from a speaker's 12V supply avoiding ground loop and interference

I have an older speaker with an iPod dock that I would like to extend with a Raspberry Pi as a streaming music player. At first, I tried powering the RPi from the dock connector with a Micro USB ...
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2answers
93 views

How exactly do inground electric dog fences work? I need help making a square perimeter with one side that dose not trigger the collar [closed]

I need help laying out an in ground electric dog fence in a square formation with one side of the square not triggering the collar. The issue it that the manufacture says that inorder to do that we ...
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1answer
54 views

Bluetooth and Wifi range onboard a boat

On my sailboat the range of wifi and Bluetooth appears to be very much shorter than in my home - I can't figure out why. ex1: At home I can stream video with Miracast from my basement to a room ...
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1answer
38 views

How do LTE radio networks deal with co-channel interference?

In 802.11 Wifi, I've read that a wifi adapter (like my laptop's wifi adapter/radio) will use Energy Detection to see if a channel is busy (if a certain energy threshold is detected on the channel, it ...
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1answer
42 views

Automatic mute radio on power-off [closed]

I have a small FM radio module I bought off eBay that runs off a few AA batteries, and have it essentially plugged right into a pair of PC speakers I have on all the time. To save battery power, I ...
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1answer
57 views

How many WiFi networks can operate concurrently?

Very hard information to find since Google always falls down in how many devices can be connected simultaneously to a single one network. Is there a limit to how many different WiFi networks can work ...
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1answer
137 views

WS2812b interference and bootup behavior

TL;DR: how can a slowly rising power supply voltage on an arduino crash the WS2812bs connected to it? How can I protect a signal wire even better from electrical interference? This my question in a ...
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3answers
180 views

What happens to parts of induction cooker magnetic field not covered with the pan?

An induction cooker works like this. There's a flat coil of wire under the cooker surface which is connected to a source of high frequency AC and it produces an oscillating magnetic field with field ...
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0answers
18 views

Downsides of Extending a USB Bluetooth Antenna?

I found an interesting video about how to extend the range on a USB Bluetooth antenna by resoldering a new antenna in its place: (https://www.youtube.com/watch?v=cwKWOdOHiWY). I'm planning on using a ...
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0answers
44 views

Prevent Reception from an Extended Distance (Beyond Design)

I have a magnetic field that is being induced onto a power line by a transmitter, which is following the length of the power line to the receiver. The receiver communicates via a loosely coupled coil ...
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5answers
396 views

Waves on raspberrypi camera feed, Ground loops? electrical interference?

I run a video recorder in a vehicle built on Jetson Nano (Very Similar to raspberry pi). It runs on 5V . The vehicle has a 24V power supply. I power the video recorder with an automotive-grade 24V to ...
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2answers
131 views

Fixing power supply interference issue (?)

I am working on a project that involves controlling WS2812B led strips using a Teensy 4.0 microcontroller. I got everything working during the testing phase, but now, after transitioning from ...
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0answers
74 views

How to prevent common ground circuits messing with each other

I made an Arduino based 18650 battery tester that has 4 identical circuits that charge and drain. Testing one battery at a time gives one set of results which I deem to be correct but testing more ...
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2answers
449 views

What's this noise?

As in other years at precisely this time I'm experiencing an effect somewhat like GSM frame-rate audio breakthrough in my auditory systems - completely different frequencies but equally wideband. I've ...
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0answers
132 views

Radio static caused by windscreen wipers

I was driving past a radio station transmitter of the radio station I was listening to. I turned on my windscreen wipers, which caused a noticeable static to be emitted through the speakers for the ...
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0answers
67 views

Experimenting with a Walkie Talkie

This is one weird bizarre thing which I noticed while I was in the electronics lab. I had this Power Supply and a walkie talkie similar to this I have not ventured in RF side yet. The power supply ...
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1answer
37 views

How to conclude the nature of interference for such scenarios?

This is abit a hypothetical question. Imagine a signal chain where a AC-DC power supply is powering a transducer and the transducer output is coupled to a data acquisition input by a BNC cable. Or I ...
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0answers
35 views

Touchscreen keeps failing to communicate with raspberry pi, except when I touch the INT pin

I bought a display with a i2c touchscreen from Aliexpress and hooked it up to my Raspberry Pi 3b+. The screen part works fine, however, the touchscreen part is flaky. When I just boot the pi, the ...
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3answers
612 views

2.4GHz WiFi module causing interference on 433MHz RF receiver module

I have a prototype board which has two RF modules on it, a 2.4GHz Wifi module (ESP-01) and a low cost 433.92MHz RF receiver module (Wenshing RWS-371F-6). My 433MHz transmitter (a remote control) sends ...
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0answers
24 views

Can these SPICE models be used to compare single ended versus 4-20mA current signals?

I want to compare the environmental or common mode interference effect to current vs voltage signals by using two different transducer types current and voltage respectively. Below I compare two ...
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1answer
44 views

PCB with 5 Pluggable RF modules and 1 LTE puggable module - will it cause issues for reception at different antennas?

I am designing a prototype PCB which shall have 5 pluggable RF modules and one 4G LTE module as shown in the image The Base board size shall be 240 x 140 mm, RF board size is 40 x 50 mm and LTE board ...
32
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2answers
13k views

Does Bluetooth interfere with WiFi?

I've read that WiFi b/g/n is using 2.3995 to 2.4845 GHz. Bluetooth is in between: 2.4000 to 2.4835 GHz. So what will happen when I put a Bluetooth sending device next to a WiFi sending device? Will ...
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0answers
27 views

Voltage variation and electrical fields Maxwell Equations

I actually know without knowing the reason or the mathematical expression of the physical phenomenon, that if we apply accross a capacitor a voltage which varies in function of the time, it produces ...
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0answers
52 views

Hall effect current sensor and proximity to EMI

I am preparing to layout a PCB. I have an ACS723, that I want to use to sense the current going through a relay. In addition to the relay I have a Meanwell IRM-12-20 to supply ac to dc voltage to the ...
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1answer
130 views

DC brush motor EMI

What kind of frequency does a DC brush motor generate? There are a few explanations online as to what causes EMI in DC brush motors (commutator sparking for example) and how to reduce it, but no ...
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0answers
50 views

How far does a PCB antenna need to be from a capacitive sensing touch button?

From my basic understanding, capacitive touch works by having a small voltage applied to a touch plane on a PCB, resulting in a uniform electrostatic field. When a conductor (human finger) touches the ...
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1answer
104 views

Can two Radar motion sensor, running next to each other, result a false detection?

I have two CDM324 Radar motion sensors. I want to run the two sensors close to each other. The transmitted frequency is roughly 24 GHz and I am afraid that a small shift in one sensor transmitted ...

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