Questions tagged [wireless]
Using other than a wired connection to transfer signals or power. Includes optical and (ultra)sound, but most often refers to RF (Radio Frequency). Distances can be as low as centimeters (e.g. RFID); there's no upper limit.
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Sensing an object’s motion using a motion sensor inside the object?
I am considering making a mouse that you can essentially use in the air. It would be wirelessly connected to a computer/laptop, and you could move it through the air to track motion in the mouse. It’s ...
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Books/Material for RF transmitter/receiver design [closed]
I am doing my thesis for my BSc in EE. Due to a lack of equipped laboratories in my universities, I cannot do a project in microwave-integrated circuits, as I would have preferred. I am therefore ...
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Can wireless charging become more energy efficient?
I've stumbled upon a few articles saying that wireless charging takes more energy to charge something compared to the cable. Like this one.
Like in the test from the article, it takes 47.33 % more ...
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How wireless charger automatic detect Rx Coil to turn on
I want to know how wireless charger can detect 2nd coil then the switching at 1st coil is on, but when the 2nd coil isn't detected by 1st coil, the switching at 1st coil is turn off. How it happens? ...
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Information sources to design a spiral PCB antenna
I am starting a huge experimental project and I want/need to explore the frequency independent antennas. I settled on two very interesting antenna topologies that are possible to design as a PCB (...
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Bluetooth trilateration using nRF5340
I am a total beginner in working with RTOS and Zephyr and nRF devices. I would like to build a Wireless Sensor Network which consists of 3 nodes (maybe set in a Bluetooth Mesh) whose primary objective ...
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How to make microcontroller such as Raspberry Pi external interruption handler for an antenna device? [closed]
I am pretty new to microcontroller, and I want to make wireless device, that actually consists of two devices:
One has a button, another has a led - when the button of the first device is pressed and ...
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How do you find Image Rejection Ratio from doing FFT on ADC samples?
I'm trying to understand a particular code written by a former employee for measuring performance of an RX chain in a transceiver. I have to measure IRR(Image Rejection Ratio).
Certain input RF ...
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Run Wifi (Intel AX210) with Single Antenna
NOTE - this was originally asked at Superuser, but they suggested I ask it here.
Is it possible to run an Intel AX210 chip using a single antenna? I've got an embedded project where a single antenna ...
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What is meant by 5G NR "Physical" layer?
I am rote-learning 5G NR concepts for a job interview. In 5G NR, we have something called a Physical layer. Wikipedia defines physical layer as:
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Is there a (legal) wireless transmission solution for my underground parkade anti-theft alarm?
I live on the 4th floor of a low-rise condo building with a concrete parkade beneath. We have a serious problem with bicycle theft -- someone is coming in late at night with an angle grinder, and ...
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How far down the OSI model does one have to go to reduce latency in wireless protocols
I'm curious about protocols used for low latency peripheral devices. The famous examples would be Logitech's lightspeed, Razer's hyperspeed and Corsair's Slipstream. The main selling point of which is ...
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ESP32 - Speeding up connection to WiFi AP and REV.3 chip woes
Esp-IDF 5.0, ESP32 Devkit1 Chip REV.3
Even with the official "station" example stripped to the minimum of code (wifi-related only), connecting to the AP with ESP32 takes 2-3 seconds. That is ...
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Total newb trying to build a wireless power transfer system for terrarium water pump
I am needing to build a induction based wireless power transfer system that I can use to power a small aquarium pump through the glass base of a very tall vase. I have been researching this for about ...
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How can I filter out the AC component of the output of a BQ51050B?
After following the design recommendations mentioned in the datasheet by placing two capacitors in parallel, of 10u and 0.1u, there still is a relatively high AC component in the output signal (pin ...
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What is "bandwidth" of wireless communication and how could it improve passive sensing capabilities?
I am currently researching existing literature for my master thesis about passive sensing using different radio-wave-modules (e.g. UWB and WiFi).
The question I would like to research is whether ...
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What is the maximum possible aperture efficiency of an antenna?
The aperture efficiency of an antenna is defined as the ratio of the effective aperture divided by the physical aperture. The typical values are between 0.35 to more then 0.70. Wikipedia
What is the ...
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When do we assume a wireless communications' channel reciprocity and non-reciprocity?
When I read wireless communications literature, I encountered both channel reciprocity and non-reciprocity assumptions for two-way communication scenarios involving A-to-B and B-to-A fading channels.
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Electronic article surveillance sensor or alternative
I'm looking for some sort of sensor for detecting certain object crossing a line or passing a gate. The sensor must detect an object from at least 1.5 m distance.
I tried to use a laser sensor but it ...
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Wireless power transfer power spikes and low efficiency
I am working a simulation model of a wireless power transfer in LTspice as presented in the image below.
There are current spikes in the input (V3) that I want to eliminate or reduce.
I have yielded a ...
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Input current too high (IR2110 driver)
I have been testing an IR2110 to drive a half-bridge inverter for a wireless power transfer application. When running the simulation, I've noticed that the input current is too high.
Can someone help ...
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Why the increase of the Spreading Factor (SF) by one, in the LoRa modulation, results in doubling of the transmission time of a symbol (T_symbol)?
Recently, I have been reading about the LoRa modulation and I am curious, why the symbol transmission time (T_symbol) doubles, if the Spreading Factor (SF) is increased by one.
The SF is equal to the ...
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Do cell-phone base station antennas emit the same power as cell phones?
Do cell-phone base station antennas emit the same power of waves as from a cell phone?
I would assume so because both waves need to travel the same distance, right?
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When should I use a Front End Module (FEM) for a Wi-Fi chip?
The WF200 from Silicon Labs has the ability to connect a Front End Module (FEM).
I have some questions:
Why should I use a FEM?
If I need a FEM, then which one fits with the WF200? Can I take an ...
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Is it possible to change the switching frequency of a Royer-based ZVS WPT circuit?
From what I have understood so far, the Royer circuit or ZVS system is self oscillating and hence the frequency is determined by the inductance of the primary winding of the coil and voltage supplied.
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Reducing temperature of the Rx coil in a wireless power transfer circuit
I have currently designed a wireless power transfer circuit which is based on the ZVS principle and Royer circuit.
The issue I am currently facing is that the receiver coil is warming up a fair bit, ...
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Attenuation and capacity
Does attenuation affect capacity for multiple narrowband signals? For example, assume there exists a 20 MHz channel with two 10 MHz subchannels. The first subchannel has frequency response 2 and the ...
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AT COMMAND's GC433-TC016 No Response
My question consurns AT Commands using a Serial Port Wireless Device. ( SILICONRA - microchip ) GC433-TC016. I can transmit and receive Serial Port transmissions to Remote units. ( GC433-TC016)
I ...
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Noise in mm-wave initial access frameworks
I have a doubt about Initial Access (IA) procedures in mm-wave system.
In most papers I have read (see e.g. Initial Access in 5G mm-Wave Cellular Networks), most of the alignment procedures assume ...
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ZVS Oscillator for Wireless Power Transfer
I am designing a wireless power transfer system based on the Royer oscillator ZVS principle. I based my circuit on the following image, this can be found in the application note [ANP032] page 21.
The ...
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How can I count the number of turns for this coil?
I am currently working on a project which deals with wireless power transfer. I am using a few coils to test out from Würth.
The coil in question is the 760308100143.
I wanted to find the coupling ...
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Parallel Resonance for Wireless Power Transfer
I have two 50 uH coils. I'm using a 68 nF capacitor for each the primary and secondary coils. This puts the resonance frequency to about 86.313 KHz. The primary coil is in series with the 68 nF ...
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Is it possible to transmit a video over a 433 MHz RF module?
Is it possible in any case to transmit a video over a 433 MHz RF module?
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Resonance Frequency Drift
I'm working on a wireless power transfer project. The coils that I'm using are made out of Litz wire with a value of 50 uH. For the capacitors, I'm using 68 nF capacitors. This puts the resonance ...
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Using a DC remote relay in low-voltage, high-current applications
I am trying to create a remote controlled miniature fog machine. My only issue is that I can't seem to find a wireless/remote relay that can work with low-voltage, high-current applications.
It is ...
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Symbol-level frequency-selective channel model representation (in OFDM)
The general symbol-level representation for a frequency-selective channel is:
$$
y[k] = \sum_{l=0}^{L-1} s[k-l]h_{l} + z[k]
$$
where \$s[k-l]\$ is transmitted symbols, \$z[k]\$ is noise, \$L\$ is the ...
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Wireless charging wire system (portable charger)
I am an industrial designer that is looking into creating a portable charger that uses MagSafe charging for the new iPhones, but I want the portable chargers to be able to stack. Through the stacking ...
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ESP32 Dev Board SPI connection
Recently, I have been given a task at the place where I am serving my internship. I have been given a pair of TTGO LoRa32 T3 V1.6.1 boards which house ESP32 microcontrollers and my task is to connect ...
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WiFi point-to-point in coastal environment - 2.4 vs 5 GHz [closed]
I am planning to provide Internet to a sea floating platform through point-to-point antennas from the coast.
The distance is approximately 300 meters and the platform is quite shaky due to the weather....
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CSMA/CA - Why does RTS/CTS with ACKS not solve the exposed node problem?
I was reading up on RTS/CTS mechanism schemes and came across this statement on the Wikipedia article - "modern RTS/CTS includes ACKs and does not solve the exposed node problem"
According ...
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Receiver Automatic Gain Control purpose
Receiver AGC objective is to have a constant amplitude signal in order to optimize the receiver performance, so it should respond according to the amplitude of the signal of interest and not to the ...
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Is it possible to connect two Bluetooth peripherals to the same master?
I would like to design a pair of identical Bluetooth devices (using the Silicon Labs EFR32BG22 Bluetooth microcontroller) which receive a data stream from a smartphone.
As I understand it, a Bluetooth ...
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Question about how a Bluetooth signal propagates out of the antenna of a BBC Microbit?
I want to know how a Bluetooth signal propagates to which designated direction in these two pictures with the strongest output from the trace antenna.
Is there any HFSS analysis image similar to this ...
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Choosing a microcontroller for a wireless keyboard [closed]
I've had my share of electronics projects and especially microcontrollers projects, having fun on STM32s lately, and I'm trying to pick a microcontroller for building a wireless keyboard but I'm a bit ...
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Full bridge rectifier and resonance for wireless power transfer in the receiver circuit
I was wondering which is the most suitable method to set up the receiver circuit for wireless power transfer circuit. Currently I have a circuit with the tesonance tank, i.e., the receiver coil and ...
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Simple wireless interface
I need to get some data from remote limit switch. The distance is 1000m ( clear line of site) or less. I can think of 2 or 3 messages to transmit: "switch closed", "switch open" ...
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Measuring a balanced matching network
I'm working with a Silicon Labs EFR32G12 Wireless MCU and I'm following their design guides for developing the matching network for the device. However, I saw that in one of their design notes (here), ...
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Beamforming antenna beamwidth/frequency relation
What's the relation between the minimum beamwidth and frequency of a beamforming antenna (such as a MIMO transmitter)? I'd guess they'd have to be on the same order? $$ \lambda \approx BeamWidth ?$$
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Is this SI4455 RF matching network well placed?
I'm designing a shielded module based on the SI4455 RF chip from Silabs. I read the datasheet and the design guidelines are pretty straightforward, I had no issues replicating most of the reference ...
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Dual band Wi-Fi antenna simultaneous 2.4+5GHz transmission
There are APs that have dual band antennas and seem to offer simultaneous 2.4+5 GHz operation. I wonder how this simultaneous dual band operation technically works (2 radios using one antenna.) A ...
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