Questions tagged [interference]

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

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1answer
55 views

Running and grounding paired shielded cable thru a connector

I need to run two logic signals around a vehicle, so for good measure, regardless if its overkill or not, I want to use a shielded single pair wire for that job. At one point it should be crimped to ...
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1answer
74 views

NFC and magnet interference in a concrete piece

Do you know if both NFC and a magnet would work correctly in this scenario? I´m designing small pieces of concrete (imagine chess pieces) with three layers: magnet inside, NFC tag in the middle, and ...
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2answers
78 views

Flashing random LEDs when multiple wires fished through hole

I've been building a large, 3D printed dodecahedron infinity mirror. Prior to adding the polycarbonate pentagons with mirror film applied, the LEDs worked perfectly in the frame. Once I fished the ...
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2answers
117 views

What can negatively impact a motherboard's / CPU's clock generator / oscillator?

Is it possible for a clock generator / oscillator to be skewed by something from the electrical grid (e.g. to work perfectly fine at place A, and have issues at place B - all reproducible)? What would ...
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1answer
64 views

Bluetooth antenna on top of large metal object and other RF questions

I've been doing some research on RF antenna design considerations but haven't really found anything close to the situation my device will be in. I am designing a wireless sensor for my FSAE team that ...
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2answers
35 views

RF interference in high node density 2.4 GHz networks

These days, there are a lot of products that are working on 2.4 GHz RF - mobiles, laptops etc using 2.4 GHz wifi, earphones using BT, home automation products using 2.4 GHz zigbee. Though these ...
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2answers
56 views

How best to allocate signal wires to 4 twisted pairs that best reduces inteference

I have to transmit digital signals 30meters including power. I am going to use a cat 6 ethernet cable with 4 twisted pairs (8 wires in total). I can already assure that my signal gets to the other end ...
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3answers
53 views

Relay is switching by touching optocoupler with finger

To switch a 12V relay with a micro controller, I designed ("borrowed") this schematic. Build the pcb and it works great. But there's a little bug that got me a bit worried. If I touch the ...
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1answer
70 views

Desktop screen goes black because of radiowaves from phone?

I hope this is the right community for this phenomenon. For some weeks my desktop screen went black for some seconds - no warning prompt no nothing - and then came back to life. I usually change my ...
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0answers
118 views

How to stop LED EMI on capacitive touch sensor TTP223

I am trying to make a piece of wood touch sensitive. I have a piece of wood carved with runic letters. I inserted LED's inside then filled the letters with epoxy resin. When I touch one I want the ...
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0answers
33 views

RF line: routing it orthogonal over SPI digital signal lines

SPI will be kept below 1MHz. RF signal is under 434 MHz. Is this crossing fine through the big zero ohm resistor ? Side question: will the outermost SPI line (it is the chip select one), or any of the ...
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4answers
725 views

Why does analysis indicate that ground lifts do not fix ground loops?

Note: "Ground loop" in this question refers to a ground loop caused by linked magnetic fields. (Sometimes ground loop refers to slightly different scenarios.) Recently I've been looking into ...
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1answer
85 views

Oxygen sensor voltage changes when machine is powered on. Interference?

I built an Arduino Uno based control panel for an altitude training machine, which connects to an oxygen sensor. The value is amplified by an instrumentation amp (INA122P) and read into the analog ...
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3answers
65 views

Better to Opto-Isolate on Sending or Receiving End? Isolating to Avoid EMI

I am working on an art project using some modified bug zapper circuitry to produce loud and bright sparks. I have the circuit working and the sparks are very impressive, but I'm running into a issue ...
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1answer
60 views

Protecting against static interference/noise for encoder

I have a chassis that is made from box steel beams, they are painted/surfaced. Attached to it is a fiberglass tub which can rotate. Attached to the fibreglass tub are supports and mounts where some ...
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135 views

Why does my Ethernet upload speed go to 0 Mbps when connecting an RGB LED strip?

I recently installed the following RGB LED strip on my bedroom's ceiling: The computer and the lights share the same electrical connection. However, everytime I plug the lights into the wall my ...
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2answers
125 views

Best configuration for ethernet-as-speaker-wire?

I'm hooking up a couple of small speakers (3w max each) outside, and I have a small run in my house from inside to out that was done with ethernet cable. There's no way I can pull speaker wire through,...
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1answer
125 views

Power Supply issues with CAN bus

I am currently working on a system using C# for a windows GUI with an Ixxat USB-to-CAN and an STM32F303K8 that runs CANopen, The system itself is running fine I can send and receive messages to and ...
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2answers
153 views

I2C gets Interference from motors in an Arduino project

I built a small Arduino "robot" on a tracked chassis. The device uses MPU-5060 for direction finding (on a prototype shield) and Adafruit MotorShield v2 to control two 320-type motors. The ...
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1answer
96 views

SMPS grounding interference ... ground loop maybe?

I am experiencing a weird phenomenon with my class 1, 15 Volt, 1000 watt SMPS with an isolated input and output grounds. The AC input (PE) ground connection has continuity to the SMPS chassis. When ...
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0answers
51 views

Is it ok to have two stepper motors right next to each other?

Would there be any issues having two nema 23 stepper motors laying right next to each other, facing opposite ways (see image)? 48v, 4amps.
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3answers
166 views

Decreasing I2C SDA SCL interference

I am setting up a fast I2C communication between a microcontroller (STM32, master) and an FPGA (Zynq-7000, slave). Currently, it won't work correctly because whenever the FPGA pulls down SDA, it ...
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1answer
75 views

DIY electromagnetic shielding (CNC mill)

I'm building a DIY CNC router. I'm running at a low RPM and only planning on cutting soft materials (wood and under, maybe a PCB). I'm currently having problems with magnetic interference. When ...
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1answer
62 views

LTC5599: why are these baseband inputs passed through 49.9 ohms and the capacitor + SPI

I'm designing a radar transceiver board using the LTC5599. In the datasheet for the part, there is a schematic that shows the circuit configuration for the evaluation board. Here is an image of the ...
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0answers
58 views

IR reciever somewhow being triggered by cell phone screen?

First time asking a question here. I am curious why the TSOP4838 ir sensor is acting eratically when my Google Pixel 2's screen is facing it. As you can see from the schematic, I have a 555 arranged ...
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2answers
50 views

Shielding an RF module from noise

I feel like a fool. As seen in the image below, the nRF module is right next to the VIN terminal. When I powered this up, I was able to communicate with the nrf module via SPI but it wouldn't receive ...
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2answers
153 views

Cross-Talk/Interference between UART Lines on a PCB

I am wondering at what distance UART lines begin to interfere with each other? And can I expect the UART lines below to function properly? The PCB board below has 6 UART lines running alongside one ...
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0answers
40 views

Basic shielding practice for simple passive audio project in an enclosure?

I'm a tinkerer but not an electrical engineer. I'm constructing a stereo->mono summing box for my stereo (to listen to Beatles LPs properly, natch). I'm using the design & schematic here for ...
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1answer
100 views

How to know which radio frequency is free to transmit data over a particular frequency to avoid interference

I found that some radio broadcasting stations transmit data at a particular frequency, and I was told that if I were to transmit my own at that particular frequency that I would interfere with their ...
2
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2answers
176 views

Shielding powerful HF EMI

I'm trying to install a plasma cutter on a CNC machine, but the problem is that the cutter uses a high-power HF start to initiate the cutting arc, and this causes horrible interference with my control ...
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2answers
50 views

Multiple AC-DC power supplies or use DC-DC converters and one power supply?

I have an electrical control box that needs 48v, 12v, and 5v to power stepper motors, sensors, and microcontrollers, respecitvely. All power items will be mounted on a DIN rail right next to each ...
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1answer
63 views

Correct model for interference from an unterminated transmission line branch

Question about the correct mathematical model for a branched transmission line Baseline Setup Waveform generator: Output 10-60MHz sine wave, 8Vp-p, Output impedance 50Ohms RG58 50Ohm coax: ...
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1answer
1k views

What types of cables do ferrite beads/chokes have a beneficial effect on?

Ferrite beads prevent electromagnetic interference from affecting a cable. Without fundamentally understanding how EMI works, this is obviously a beneficial effect for the stability and integrity of ...
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1answer
32 views

What's the logic inside the formula for the calculation of the maximal envelope modulation amplitude of two temporal interfering electric fields?

Since my question is a bit elaborate, I will first write some details. Thank you all! I refer to the study conducted by Nir Grossman et al. (2017) about the use of the temporal interfering stimulation ...
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2answers
105 views

Arduino resetting or malfunctioning when controlling 48V DC motors with relay module

I'm building an Arduino controlled crane machine out of old crane machine parts. The motors in a crane machine are 48V DC and I am controlling them with an H-bridge configuration using an 8 channel ...
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0answers
55 views

Do I2C wires and 120W (12V) power wires close together cause trouble?

I'm a beginner with electronics and I'm building my first solar powered robot. I now have a 50cm long (1.6 feet) small pipe through which I want to put four wires; 2 for the power from the solar ...
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1answer
49 views

Weird interference when controlling piezoelectric humidifier

I am trying to build an Arduino controlled piezoelectric humidifier. I am using two humidifier modules which have 5V dc operating voltage(they have usb connectors). When I connect one module to my ...
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1answer
107 views

Top layer vs mid layer for high speed ADC signal routing

Assuming we have an analog differential signal trace that we must route from the connector to,say, an ADC (24 bit or 32 bit kind as I don't think lower resolution ones are affected by this.) What we ...
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0answers
31 views

Will using a relay for triggering remote send interfering signals?

So I have a remote control with a SMD button I want to trigger. To do so, I need to bridge horizontally a pair of the pins, as shown in blue: However, when testing this, I connected a long (10cm) ...
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1answer
72 views

Nearby jail's signal jammer affecting cellphone and devices using 2.4GHz band

I just rented an apartment that seemed perfect at the first sight. However, once I moved in, I noticed a lot of instability on my cellphone signal. I found that odd, so I did some research and ...
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2answers
128 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
59 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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1answer
66 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
65 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. ...
3
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1answer
82 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
385 views

ESP8266 noisy input when wires go through power supply

I had made a circuit for an LED strip using an EDP12e. I had also attached two buttons to change between colors on the strip. To make it compact I inserted the circuit board inside the casing of the ...
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0answers
123 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
99 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
78 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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