Normally related to EMI (see [tag:emc])

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1answer
80 views

Microcontroller freezes (or doesn't) when plugged into different outlets in my home

I have an ARM development board (Marvell ARMADA XP CPU) and depending on which plug outlet I plug the system into, the system will freeze up after a few minutes or not. I found that plug outlets in ...
3
votes
1answer
97 views

Multiple nrf24l01, shared power, ripple/interference, DSO screenshot provided

I've got this circuit with 3x atmega328 & nrf24l01+ running off shared power supply, either 2x AA battery or 3v3 reg. It acts as a repeater, and depending on the origin of the message and the ...
1
vote
1answer
33 views

Reduce Interference in Wireless Mesh Network

I am playing with the idea of mesh network path finding. The goal is that each node can find the most efficient path through other node to a hub. One way I could approach it is by flooding the ...
0
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1answer
49 views

How do I place a long wire to make the EMI and inductance minimum?

I'm going to measure high current. After seeing that there is not a lot of low valued sensor resistors in the market and the available ones are very expensive, I decided to make my own current sensing ...
0
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0answers
27 views

How much electromagnetic interference/pollution is produced by home power-line network adapters?

How much electromagnetic interference/pollution is produced by home power-line network adapters? How do they compare for example to WiFi routers? They operate on high frequencies to achieve high ...
2
votes
2answers
51 views

Trying to Understand Spurious Sideband Interference (and some causality problems…)

Suppose I have a radio and I intend to transmit a 0.1 µs pulse on a 100 MHz carrier. Fourier theory tells me that this signal will produce some sideband interference resembling a Sinc function. ...
1
vote
1answer
79 views

NFC tag interfere with hearing aid device

I want to add NFC tag to hearing aid device for a child to monitor on smartphone (or smatwatch - either carried by children) if the tag is in the range - if not it means that child lost it and I can ...
3
votes
3answers
350 views

50MHz SPI PCB routing, use vias or resistors?

I am trying to route the SPI between MCU and ADC. However, the pin orders between MCU and ADC are not matched, there are crossings. A four-layer board is used.(signal - ground - power - signal) I ...
3
votes
4answers
337 views

How to prevent PA system from interference of 4G signal

I apologize if this is not the right place to post this. I am working on a small PA system for a weekly gathering. It catches the signal from wireless mics and output it to the speakers. I am pretty ...
0
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2answers
177 views

Stepper motor failing. Electrical interference?

Update: This question is already so long, I'm hesitant to add to it but it occurs to me to ask if electrical interference between the stepper motor wires could cause this sort of behavior (motor ...
3
votes
1answer
66 views

Audio oscillator cross-talk on small synth project

I am making a small 9V battery powered synthesizer with a square wave oscillator built around a 40106b Schmitt trigger (reference: http://richdecibels.com/blog/?p=11) and a few other components, one ...
4
votes
1answer
819 views

Permanent magnets near wifi device

Background I have a small circuit that consists of a microcontroller operating on 14Mhz and a wifi module. This circuit is enclosed in a small plastic box. I am considering gluing a few magnets on ...
2
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2answers
143 views

Verifying design that uses guard ring

I had a colleague design a board for pH sensor amplification based on schematic (fig 1)and spec in a paper. The paper recommends using the spec noted in figure 3. It uses a guard ring to reduce ...
6
votes
3answers
147 views

What Regulatory Requirements are Really Necessary for Sale in the USA?

I understand that unless you fall into some specific product categories that are exempt from FCC regulations, electronic products sold in the US are legally required to meet FCC EMC limits. However, ...
16
votes
4answers
1k views

How come radio signals don't interfere with each other all the time?

I'm a newbie on wireless technologies and I'm trying to understand how they work. One thing I don't understand is this: How come transmissions from different devices don't interfere with each other ...
3
votes
1answer
231 views

Why do library book detectors make my headphones buzz?

Whenever I enter or exit a library while wearing headphones (cheaper intra-aural type), I hear loud buzzing as I pass through the book detector gate. I can vaguely speculate at a high level that ...
1
vote
1answer
72 views

Can mobile cell stations cause interference in audio circuits near them?

It's a fact that if you put a GSM cell phone near a desktop PC and call it, the phone will interfere with the audio card and cause that noise most of us have heard somewhere. But is it the case with ...
3
votes
3answers
118 views

Are Wi-Fi 'transparent' buildings superior to antennas mounted on the exterior?

Looking in particular at wireless mesh networks in cities - is it advantageous to design a building that does not interfere with Wi-Fi (e.g. out of wood instead of steel and concrete), or would ...
9
votes
1answer
438 views

PCB clearance/keepout area surrounding wireless antenna

Suppose a PCB antenna or chip antenna is integrated onto a board design with a wireless IC, e.g. a Zigbee or Bluetooth module. What are some guidelines regarding clearance/keepout area on the PCB ...
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2answers
92 views

Radio or TV signal interference

I am curious to know why can not signals of different tv stations mix together while transmitting. I have seen many towers built near each other in mountain areas in my country. If two different ...
0
votes
1answer
136 views

Inductive phone charger mod - doesn't work with battery too close?

I am experiencing a strange issue, likely because I do not fully understand the technology I am trying to make play nice together, but maybe someone here can shed some light on it. I have an HTC Evo ...
2
votes
1answer
129 views

Possible wifi interference with processor

I am building a device that consists of an ordinary WiFi router (WDR4300) as shown here: Which works as a client and scans for networks OK when alone. The problems appear when I add another board ...
0
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0answers
146 views

Prevent interference caused by fan

I have several strips of addressable (LPD8806) LEDs hooked up to an Arduino. simulate this circuit – Schematic created using CircuitLab I have noticed that whenever I turn off a fan ...
0
votes
0answers
40 views

Will this RAM bypass interfere with linux's total memory count? [duplicate]

As the patent in this question shows, it may be possible to hijack a computer by bypassing the memory controller. If it's true that it only hijacks part of the RAM at a time, does that mean that it ...
0
votes
1answer
80 views

Should I use Magnet Wire as a conductor in this experiment?

I need to run a few wires from a HMC5883L compass sensor to a micro-controller to process the data. Can I use magnet wire to carry the signals from the sensor to the micro-controller or would the ...
16
votes
5answers
1k views

Why does a simple conductor start to emit EM waves when carrying a signal?

I understand that on circuit board traces with a clock, if the higher harmonics have sufficient power, it results in electromagnetic waves being emitted from the traces which creates EMI. What I don't ...
0
votes
1answer
159 views

Could an aluminum housing and passive cooling interfere with SoC's functioning?

I took the board out of a broken tablet. The SoC on the board gets hot pretty quickly. I thought about fixing the board to an aluminum plate, so that it touches the SoC and disctributes its heat, and ...
1
vote
1answer
176 views

I2C on FFC or IDE cable - interference?

This is a follow-up question on this answer. I need to communicate with I2C over approximately 10cm and I'd like to use an FFC or IDE cable for that. Earlier, I used an FFC cable to link a segment ...
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1answer
218 views

Bluetooth Interference between piconets

I am developing a device that consists of a base station and several wireless sensor nodes. In application there may be up to 30 of these devices in a laboratory with up to 5 sensor nodes ...
4
votes
2answers
344 views

Why are low frequency channels (10kHz - 200kHz) especially susceptible to interference?

I am working on a system which should communicate with a ~100kHz signal, and read that low frequency channels, e.g 10kHz to 200kHz, are especially susceptible to interference. Why is that? Are they ...
0
votes
2answers
416 views

Computer case causing interference with TV

I've recently changed my computer case to a new, bigger case. However, after I changed this case over, I can no longer watch TV due to interference with the signal. I have removed every output to my ...
12
votes
4answers
2k views

Microcontroller with a long wire for digital input

I have the doorbell button on my house wired into a GHI EMX dev board. The software evaluates the time of day and determines whether or not the doorbell should ring. Side Note: This was ...
0
votes
1answer
202 views

BBQ iginter power surge

I am building a home beer brewing rig that has several electrically actuated components controlled by an Arduino. The typical scheme is Arduino -> Shift Register -> Relay -> Component. One of the ...
1
vote
1answer
282 views

Can my weather station cause interference with my wireless network?

I know my weather station is on 433 MHz and my home Wi-Fi network is on 2.4 GHz and 5 GHz. It's ok so far and everything seems to be fine. But I found many cases on the Internet that cheap stations ...
2
votes
2answers
568 views

Would a digital compass work reliably when installed in a car?

I'm working on a project that needs dead reckoning sensors to combine to GPS readings, and is to be installed under the dashboard of a car. Currently I have an accelerometer and a gyroscope for that. ...
1
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1answer
541 views

How close can I place two transformers?

I need to place two of these transformers in a case. How close am I allowed to place them? Can they touch each other (of course, they will be electrically isolated)? Is their orientation with ...
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votes
1answer
233 views

Jamming Devices [closed]

Im am thinking about building a low power broadband jamming device to blanket a small area, around 400 sq.ft. I want my frequency range to be from DC to 100 ghz. Would amplifying the outputs of noise ...
11
votes
2answers
1k views

FCC part 15 “must accept interference from other sources”: what does this mean?

I've googled around a bit and here are the interpretations I've found in non-authoritative sources: that the device is unable to filter out interference caused by other certified equipment that if ...
0
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1answer
717 views

Could a bad hdmi cable be the cause of 60hz speaker hum?

I was at a friend's house trying to help him get his computer/tv/stereo connected in his new apartment. We had some difficulty getting the tv to acknowledge the video signal. The hdmi source option ...
2
votes
2answers
503 views

Ground induced noise between two connected boards

I have a CNC system that consists of a CNC controller connected to a PC via USB. The controller is in turn connected to a stepper motor driver board. My problem is that some time the turning off/on of ...
3
votes
2answers
396 views

Does RFID interfere with NFC

i have a small question about interference. Do active RFID (860 MHz) interfere with NFC cards (13.56 Mhz) when placed on top of eachother? (NFC above RFID tag for example). Thanks!
1
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2answers
4k views

What is the definition of interference vs. noise in radio communication?

Is it defined by the source or by the nature of the waves? Can one with some instrument make a reading like "In this room we have this level of interference and this level of noise"?
8
votes
2answers
1k views

How to build a cheap device to determine where Wi-Fi interference is coming from?

In this post, the ServerFault guys use a fancy tool to map out the WiFi spectrum under normal conditions, with a microwave running, and with a baby monitor on. The baby monitor and microwave cause a ...
6
votes
1answer
989 views

Killing GSM Buzz with Ferrite Beads

I'm trying to rid my speakers of the typical buzz from my iPhone. I get poor reception in my apartment and so it's constantly trying to find a signal, meaning I get a near-constant buzzing when the ...
12
votes
1answer
2k views

How to shield microcontroller from electromagnetic interference

I'm working with high voltage circuit (2.1 kV for defibrillator capacitor testing) and I'm controlling power supply with arduino, reading required information from laptop using serial interface. Most ...
1
vote
2answers
124 views

Will this setup create much audio interference for me?

I'll be installing a ipod adapter kit in my 2004 honda accord, and on the device that connects to my stereo, it includes stereo outputs - red/white - that i can connect with a stereo to 3.5mm cable to ...
17
votes
5answers
7k views

What is causing large oscillations in my DC/DC boost converter? Is this ground bounce or some other effect?

I designed my first PCB for a DC-DC boost converter only to find that it produced very noisy output. The design is based around the MIC2253. Here's a schematic: Although my circuit allows for ...
0
votes
1answer
168 views

Whether RF affects LPG Gas Sensor sensitivity or can it be hazardous, like fire and all?

I want to make a wireless electronic LPG gas leak detection solution. I want to start with any of two sensors MQ2 (How Catalytic Combustible Gas Sensors work?, DataSheet, Another DataSheet, Tech ...
10
votes
4answers
597 views

Why is RS-422 interface interference insensitive?

I am trying to understand differences between RS-232 & RS-485. I just don't grasp what is the core principle behind RS-422 inteference resistance? Is it number of wires (4 instead of 3)? Is it ...
6
votes
1answer
1k views

What should I know about interference between wires in a multi-conductor cable?

I want to use a multi-conductor cable for a few different circuits. What do I need to know about interference between circuits within a multi-conductor cable? Some of the wires will carry stepper ...