Using other than a wired connection to transfer signals or power. Includes optical and (ultra)sound, but most often refers to RF (radio-frequent). Distances can be as low as centimeters (e.g. RFID), there's no upper limit.

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6 views

Xbee communication overlap

I'm setting up a mesh network with Xbees S2. I have: 1 Coordinator 1 Router 3 Sensors I set the same PAN ID to all of them, and it seems they are connecting as they should. Now I need to send some ...
0
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1answer
16 views

ETSI Tx Power standard for short Range Devices. I am Confused

I came across the European Telecommunication Standards Institute (ETSI) standard for non specific Short Range Devices which is documented in EN 300.200 . On page 28 under Section 7.2.3 with Heading ...
-4
votes
1answer
50 views

How to transfers sensor data through WiFi? [on hold]

I would like to send data from 10 sensors from arduino to a laptop connected to the same wifi network. Can anyone guide me on this task.? Advance Thanks. I have only WiFi no internet.
0
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0answers
30 views

How do I learn to design a Bluetooth Low Energy board using TI CC2650? [on hold]

I wanted to make a 15mm square pcb using the free version of Eagle (2 layers). I have read quite a bit, but I am not confident I can make a board that radiates to 1.5 meters (at least). I have so many ...
0
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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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0answers
24 views

Adding a custom antenna to a wireless extender by removing pcb insulation and soldering to the board

I recently bought a WN2000RPT. Its a very weak extender and for it to be useful to me I will need to add an antenna. As the board comes it has two inbuilt antennas. My plan is to use sand paper to ...
0
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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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2answers
48 views

Identification Technique

I'm building a 20cm x 20cm table that is divided into cells, it has 4 rows and 4 columns. There will be different external blocks that have numbers, each block can stand on a single cell, each block ...
0
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1answer
15 views

Two-Ray Ground Propagation Model or Free Space Propagation Model

May I know that when we want to estimate outdoor transmission performance between two wireless points, which model,Two-Ray Ground Propagation Model or Free Space Propagation Model is more suitable? ...
0
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0answers
24 views

Necessity of off-resonance operation of tightly coupled coils for maximum efficiency?

On Wireless Power Consortium webpage there is an article about Magnetic Resonance. These paragraphs in the page surprised me (emphasis is mine): You might expect that operating tightly coupled ...
0
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0answers
37 views

wireless on/off switch for LED using RF transmitter reciever

i wanted to switch on an LED using an RF transmitter receiver like we can see in this video (https://www.youtube.com/watch?v=jeRtyOgf0mI), although i do not want the morse code application, i just ...
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votes
2answers
131 views

Lighting a LED with only one wire

Is there any way to light a LED using only one wire? I mean, can you use a capacitor or something similar on the other pin of the led to "close" the circuit. Keep in mind that I need to light the LED ...
-3
votes
1answer
105 views

Why does the Apple Watch use a wireless charger, even though such a charger works slower than a MagSafe-like wired connector would? [closed]

The Apple Watch includes a built-in lithium polymer battery (a few hundred mAh; slightly more than 3.75 V) which is recharged using a wireless inductive charging cable. The cable does use magnets to ...
-2
votes
1answer
84 views

wireless device to send data with low latency up to 1km

I need a device about the size of a phone with 2 buttons, the device will be used to let a server know the outcome of an event (2 possible outcomes). A mobile phone app would be the obvious choice but ...
1
vote
1answer
60 views

is multipath the real cause of small-scale fading?

Since I was a student I've been told that small-scale fading is due to multipath propagation. With multipath you get constructive and destructive interference making the signal received power fade. ...
2
votes
1answer
63 views

Can Bluetooth beacon be detected while it's in motion?

I'm curious to know if smartphones can actually detect Bluetooth beacon which is in motion, say while driving. Can car A detects the beacon in car B if they pass each other? If yes, what is the speed ...
1
vote
2answers
47 views

Can I reposition the induction coil in a Qi charger

I have recently bought a Qi wireless charging case for my phone as a car mount that I was bought for Christmas had a Qi charger build into it. Both work well, but are the coils are misaligned by about ...
0
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0answers
34 views

Interfacing two BLE devices with no UI

I'm wondering what the best way to connect/pair two BLE devices which have no screen. Most applications with BLE use a smartphone, tablet, or computer as the central device, and in these cases it is ...
6
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2answers
306 views

Wireless communication under water

I am looking for a under water wireless communication, distance up to 3000 meters. For this I quickly did some research on it and found out that Acoustic communication would be the best solution since ...
2
votes
2answers
287 views

Wireless data exchange up to 2 bytes/s

I would like to set up communication between two Arduinos with a distance of 20 cm, but not more than 40 cm. I looked for an RFID solution, and I found a lot of PCBs which can be used to ...
0
votes
1answer
108 views

Does Bluetooth 4 or 802.11b/g/n penetrate through walls better?

I'm thinking of building a signal beacon designed to be used indoors. The transfer speed isn't critical but range and penetrative ability are. Does anyone know if Bluetooth 4 or 802.11b/g/n might be ...
3
votes
2answers
126 views

How Channelization code is shared in HSDPA?

I am on my way to understand the HSDPA/HSUPA technologies. I have just started and came upon the topic of channelization code. I learned how these codes are generated - Hadamard code technique - and ...
0
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0answers
34 views

Why does this smart card use antenna with different space between turns along different sides?

I've extracted and zoomed to 400 percent parts of image from this post. The original image features the inner parts of Visa PayWave enabled smart card. Here're card corners zoomed to 400 percent so ...
0
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0answers
37 views

Bluetooth serial to bluetooth audio module

I was looking to work with a bluetooth audio module but many of the available options are either very costly, unavailable in my region(India) or generally lack some features. What is commonly and ...
0
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0answers
10 views

The transmitter address is different from the AP to which my station is associated. Will this cause a problem?

Assume that this is a necessary evil for the moment, due to cases such as a broadcase frame being sent out by an AP with many virtual access points. Does it ignore the frame? Will it accept and ...
0
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0answers
29 views

How do I sniff packets with a Zulu chip based on Si1000?

Tried to ask the question in another SE but was directed here. I'm trying to sniff the communication between Z-Wave devices. I've set up a "smart home" consisting of a few devices using Z-Wave ...
1
vote
1answer
82 views

XBee Synchronization

I am using 64 XBee modules (XB24-Z7UIT-004) as sensors and I am trying to synchronize all the modules to execute a command all at the same time. What happens is that it takes about 500ms to send the ...
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2answers
63 views
0
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1answer
47 views

What is the speed of a baud rate? - RN42

After wondering/researching about this for days, I finally ask this question: What is the speed (bits per second) of a bluetooth SPP RN-42 device? Is 1 baud = 1 bit (thus 9600 baud = 9600 bits per ...
0
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0answers
21 views

RFBee corrupted, not working

I was working on multiple RFBees, 1 receiver node and 4 sending nodes and, sending data at a very low packet interval of 30ms [Duration between each packet sent from a node]. I sent around 2000 ...
1
vote
1answer
75 views

How do you implement wifi with a front-end chip?

I was looking around for a solution to hook up an application with an MCU to a wifi network. I'm basically looking for a chip that can talk to my MCU via an interface like I2C or SPI and is able to ...
4
votes
3answers
159 views

Possibility of an extremely directional antenna

I'm fairly new to RF technology, but a direction-finding application has come up where a highly directional antenna can offer a convenient solution, so I started searching for such antennas. Most, ...
0
votes
1answer
52 views

TI RF solution - MSP43x+CC1100 vs. CC1110, toolchain

I'm looking for low-power RF solution working in sub 1GHz band (868MHz, battery powered, mostly sleeping). Originally I considered AVR with Digi Xbee 868LP module but doing deeper research I found TI ...
1
vote
2answers
74 views

I want to send and receive data wirelessly from 90 different areas to a central collection site. longest distance is 8.5 miles.

I have 90 pump/lift stations that I would like to send information from to a central collection place (office). The longest distance is 8.5 miles away. most of these pump stations are line of sight ...
0
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0answers
23 views

Q: FCC/EC pre-certification: is it required for evaluation/development kit?

I would like to add a wireless (Sub 1-Ghz or 2.4Ghz-based) connectivity option to an development kit and wondering if FC, EC, and alternative certifications are necessary for this add-ons. As far as ...
0
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0answers
25 views

XBee Pro 900 RPSMA not detecting

I bought 2 XBee Pro 900 RPSMA from Sparkfun.One of them is detected by XCTU but same other one is not detected by XCTU. so I tried recover faultly one by seeing this video ...
2
votes
1answer
26 views

Impact on the battery life of a wireless mouse based on a using practice [closed]

While using a wireless mouse having alkaline batteries, does it matter to the life of batteries, at what distance from my computer I use it? I mean, if I use the wireless mouse from a far distance ...
0
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0answers
44 views

What's the purpose of these peninsula-like areas in this smart card circuit?

Here's a scan of a stripped MIFARE Ultralight smart card. Note the underlined peninsula-like areas. They are simply connected from one end to the antenna track. They don't look like a patch antenna ...
5
votes
2answers
70 views

Why is outer turn of this smart card antenna wider than the other turns?

Here's a scan of a stripped MIFARE Ultralight smart card. Most of the wiring is the antenna which effectively consists of a single spiral track. The outer spiral turn clearly is a bit wider than the ...
1
vote
1answer
62 views

Reliable way to transport data over 1-2 km distance

I am looking for some way to transport data (around 3000Kbps) omnidirectional. Transmitter should not weight more than 300 grams but receiver can be much heavier. The range I am trying to achieve is ...
-1
votes
1answer
283 views

Can a Bluetooth wireless connection bridge a USB Host and USB device?

Now that Bluetooth modules are dirt cheap, I'm wondering if I could make a pair of wirelessly connected objects that would act as a "virtual USB cable". One would have a pig tail with a USB Male plug ...
1
vote
1answer
61 views

FSK combined with either ASK or PSK?

Why is it that we are able to combine Amplitude and Phase modulation (Resulting in QAM) but are not able to do so with frequency? Why not combine all three degrees of freedom (Amplitude, Frequency, ...
0
votes
3answers
84 views

Transmit an internet connection over wireless

My target is to transmit an internet connection (8 Mbit/s) over long range wireless RF (7.7 km) with LOS (Line Of Sight). I live in a country where there is no rules for RF transmission, so i can use ...
0
votes
1answer
150 views

Is moving fast will effect WiFi transceiving beavior?

Let's say I'm driving a 2010 Bugatti Veyron 16.4 Super Sport, with speed of 431 km/h = 268 m/h = 119 m/s Now I have a WiFi signal receiver installed on the top of the car and a WiFi transmitter in ...
1
vote
1answer
66 views

Transmit 12v power wirelessly

Is it in any way feasible, in a small form, to power a 12v light with a power source or transition source 3" away without any physical connection? ...
0
votes
1answer
59 views

Choosing a RJ45 to WIFI adapater for use with Embedded Server

I wanted to build the classic web page that turns on and off an L.E.D. My plan was to use one of the Atmega line of micro-controllers with an enc28j60, which seems to be a popular solution to this ...
0
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0answers
58 views

Recommendation for proper relay to trigger wired doorbell with wireless intercom

I was just searching my question and found someone on here recently asked this question: I am looking to do exactly the OPPOSITE of this. I would like to use the pushbutton of a wireless ...
0
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0answers
31 views

About bluetooth 4.0 modules auto connect

I am new to Bluetooth 4.0 cc2541 modules with pins and baseboard. I am currently working on bluetooth 4.0 modules with the STM32F407VG for the wireless robot controllers which is my final year ...
1
vote
1answer
76 views

Interfacing a GPRS chip (WISMO218) with an RF antenna. Calculating line width for the right impedance

I want to interface the WISMO218 GPRS chip with an antenna. The antenna lines on the PCB board have to be very specific, otherwise the system won't work. I have uploaded the part of the datasheet that ...
1
vote
3answers
90 views

Dipoles lengths underwater vs on land

A submarine (for example) uses a VLF communications system to remain in contact with its headquarters while submerged. The submarine drags a resonant dipole wire antenna behind it in the water. The ...