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

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snubber network in 110V AC contactor

How can i calculate the value of capacitor and resistor that i can use for an AC 110V AC contactor, (GE CR453CA2AAA) *coil 110-120V 50/60Hz *2 pole *full load amps - 20 Amp *resistive amps per pole ...
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1answer
24 views

Credit Card Swipe Interference

I am asking a question as a part of library maintenance for electrical equipment. We have installed a POS machine with credit card swipe on the same outlet as a laser scanner (used to check in ...
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1answer
36 views

Mobile WIFI: how close can mobile devices be placed and still have a functional WIFI connection?

I wish to run a large array (50+) of hacked Android phones as a computing cluster. They will need to be networked so I plan to use their built-in WIFI radios to talk over a single WIFI network. (I ...
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2answers
324 views

Using PC audio to listen to electrical noise on power line?

I have done a bit of research on digital filtering and I was wondering if it would be possible to use the audio hardware of my computer tu listen to the electrical noise on my powerline ? If it is ...
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2answers
43 views

2.4GHz Wi-Fi interference between devices in close proximity, even though they're using completely non-overlapping channels?

Is there any known electromagnetic / interference / [no idea] effect which can cause IEEE 802.11 (Wi-Fi) 2.4GHz devices located in very close proximity (one on top of the other) to severly interfere ...
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72 views

Will the following circuit cause EMI-problems?

I'm trying to get a feel for which circuits will have EMI-problems and which won't. To make things a bit more concrete, I've designed a super-simple LED-blinking circuit using the PIC16F1788 ...
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3answers
39 views

Via fences or pickets important parameters for design

What is more important for EMI shielding effectiveness with respect to guard traces and via fences, the width of the copper trace that circles around the area or the distance between the vias to ...
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3answers
69 views

Electrical noise sources in farms

I am designing the data logger of a solar-powered automatic weather station that will be installed in farms. It's used to gather data from environmental sensors (wired) and send it to a host using the ...
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1answer
96 views

Wi-Fi transmitter/receiver in close proximity: Override interference?

I'd like to control a camera via Wi-Fi (zoom, trigger shutter, etc.), and possibly also capture a live video stream. This will be at an event with a huge number of Wi-Fi devices, and connectivity is ...
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3answers
99 views

How does EMI affect a circuit? [closed]

I was designing pcbs and my head engineer told me that if input supply is large then there should be a separate layer for ground and positive supply as this will reduce EMI effects on the nearby ...
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37 views

LCD Flickering when Shielding is not Connected to Ground

I got myself one of these LC-Displays: http://www.sainsmart.com/sainsmart-hdmi-vga-digital-9-9-inch-1024x600-lcd-driver-board-for-raspberry-pi.html It's a barebone LCD setup with just the components ...
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1answer
39 views

GSM module noise

I'm developing an embedded system that uses telit gl865 modem to connect to a server using gprs. I've noticed that the module makes a strange noise when connected. It's the same noise I used to hear ...
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1answer
60 views

Usefulness of line EMI Filter on bench power supply

I have read this pdf file about EMI filters. I'm about to construct a variable bench power supply of 12V/5A. Will there be any usefulness to add an EMI filter to the primary windings of the ...
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1answer
53 views

Two 2.4GHz radio modules (XBee+Bluetooth) on same PCB. How to minimize interference?

I'm designing a PCB with XBee radio module and a bluetooth module (RFDuino SMD with XBee 2mW Radio). Since both of these modules are using 2.4GHz, are there any special consideration about how to ...
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1answer
68 views

Will coiling a mains power electrical cord cause interference?

I am a maker working on a lamp design in which a decorative power cord is wound through the structure, creating a coil down the lamp's main structure. The coils are about 3cm apart and the same in ...
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49 views

Parallel connection between two circuits 15cm apart

I need to connect two PCB that must be 15cm away from each other. I considered an IDC connector with ribbon cable like this http://www.zagipalma.es/images/USBASP/USBASP%2010%20a%206%20Pines%2011.jpg ...
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1answer
49 views

Multiple hall effect sensors in proximity

I'm interested in using a linear Hall effect sensor to measure displacement varying by about 1.5 inches. The idea is I have a piston with a magnet at the end and a Hall sensor at the end of the cavity ...
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2answers
202 views

How to shield for electromagnetic interference (DIY level)?

I am building an optical rotation encoder for my "autonomous robot" (a LED pointing to a photodiode that gets interrupted as the axis rotates). My issue is that at the voltage that I am using the ...
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1answer
79 views

Wireless Panic Alarm

I have made a panic button with a simple circuit with a wireless doorbell button connected wirelessly to the chiming box with the output of that connected to a relay powering a 12v flasher and siren, ...
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1answer
110 views

5V TTL signals over 4m or so?

Adding input and output capacitors either side of my 5V DC-DC converter doesn't seem to help much, and I'm wondering if some kind of signal interference might be my problem. I'm running signal from a ...
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2answers
54 views

What can be used for impromptu EMF shielding?

I have a robot with a lot of servos in close proximity and a high-current DC motor powering an airsoft gun. The motor is causing electromagnetic interference with the servos, and we need to shield it ...
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2answers
59 views

Does gauge size of a signal wire has an effect to its susseptability to electromagnetic interference?

Let's say you have the option to use a lower gauge wire size (i.e. thicker wire) for a signal wire that happens to be run along power wires. Will it pick up more electromagnetic interference than ...
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51 views

What would be some solutions to prevent system malfunction after IEC 61180 4 kV and 6 kV tests?

My team of engineers are developing an energy analyser that have to be submitted to the 6 kV transient tests of IEC 61180, Table 1 Line 8 and 4 kV fast transients tests, Table 1 Line 9. When we were ...
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2answers
103 views

Sensible standard wiring type for long-range I2C

I'm planning on interfacing with some sensor devices via I2C over a long bus, with devices chained every 2m or so, up to 16m in total. I've seen other questions here referring to this from the "which ...
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76 views

HF RFID 13.56MHz Interference from WiFi/BLE 2.45GHz?

If a Wifi/BLE antenna were placed within a multicoil loop antenna for 13.56MHz HF RFID, would there be significant crosstalk/interference?
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1answer
37 views

3 axis magnetometer issue in one axis

I have several 3-axis magnetometers mounted on breadboards, and they all read correctly in the x and z directions. The Y direction is very strange; when turned to read ...
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1answer
131 views

Strange TV Blue Screen issue on switching on any home appliances [closed]

i have recently purchased Android Tv Box CS928 from Chinese site http://www.aliexpress.com/item/CS928-Android-4-4-kitkat-Rk3288-A17-quad-core-2GB-16GB-2-4-5-0Ghz-100M/1939723909.html The Android TV ...
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1answer
61 views

Can a rotary incremental encoder, count more steps due to interferences

I have an incremental encoder having differential signals A-NotA, B-NotB I-NotI, that apparently randomly seems to count more impulses. It is possible to have more impulses due to electrical ...
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86 views

How to shield a USB device from high EMI

What is the best way to keep a USB device from disconnecting when exposed to a high EMI environment, such as when connected to a high voltage power supply under test? For example, in debugging a ...
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75 views

If my WIFI chip has poor performance at 5GHZ, what does that mean to the end user?

I'm testing my WIFI chip, and it has poor performance at 5GHZ. The transmit power I'm measuring is really low. How does this problem manifest to an end user? Will the internet connection be really ...
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4answers
3k views

Wireless Home Automation 2.4GHz versus 433MHz [closed]

Project specifications To make some things clear first(wow that sounds so arrogant): This is an Arduino project This is supposed to be internationally applicable I have experience with 433 MHz ...
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1answer
119 views

Bluetooth Interference with High Pitched Tone

i'm building a portable stereo system and am having some unwanted noise from the bluetooth receiver. the noise is typically a high pitched tone. please see the attachment for my chicken scratch ...
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2answers
79 views

Suppressing interference in a pressure sensor circuit

I just looked over a circuit designed by my predecessor, which is used to interface with a pressure sensor. It works, but I have some doubts about the way the input filtering is done. The simplified ...
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1answer
108 views

pH sensor project: trouble with RF interference

I built this pH sensor project on a breadboard and I'm having a big problem. The output on the voltmeter is completely erratic, and I'm pretty sure it's due to RF interference. When I connect the ...
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0answers
59 views

How to debug and resolve an antenna interference problem?

We have had a board made that features an interacting processor, chip antenna and GPRS/3G module. We have proved the functionality of the board - it works - but the board is not stable. We have ...
2
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1answer
50 views

Atmel and coil close on a board - is interference an issue?

I'm going to build a circuit which uses AVR uC (probably ATmega8 or some ATtiny) and a coil with iron powder ring core. The coil has 330uH and will be working under current of approx. 6A. I'd like to ...
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134 views

Isolation between GSM and GPS antenna

We are doing a prototype for a gps based tracker. We got a problem in placing the GSM and GPS antenna. Both the GSM and GPS antenna are omni-directional antennas. In forums and application notes, the ...
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1answer
250 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 ...
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1answer
415 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 ...
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1answer
45 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 ...
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1answer
74 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 ...
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64 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
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2answers
74 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. ...
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1answer
123 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 ...
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3answers
733 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 ...
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4answers
1k 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 ...
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2answers
646 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 ...
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1answer
107 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 ...
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1answer
2k 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 ...
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2answers
185 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 ...