Questions tagged [sensing]
Related to sensors and sensor systems
110 questions
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Safety considerations for designing Mains Voltage Sensing Circuit
I'm looking to design a circuit to measure AC mains voltage and current for protection purposes. I'm considering using the ADS131E0 ADC by Texas. The IC is made with power-line monitoring in mind.
On ...
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A sensor's idle voltage is 1.1 V, and its triggered output voltage is 5 V. How can I condition the signal to be <0.2 V idle and ~2.5 V triggered?
I'm triggering a high speed camera with an analog chronometer tower that when un-triggered puts out 1.1 V. When an object passes through the tower, it briefly spikes to 5 V. I'm using an old camera ...
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Modifying a TDS Module for Higher Electrical Conductivity Measurements
I recently acquired a Keyestudio V1.0 TDS module, primarily used for measuring the electrical conductivity of water. The module is recommended for 0-1000ppm or 0-2000μS/cm measurements.
However, my ...
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Tension load cell options
I'm designing something similar to an electronic hanging scale (think a heavy object on the bottom, with a scale attached immediately above it). I am not that familiar with what the most typical way ...
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How to sense the presence of AC voltage that could vary from 17 V to 230 V?
I have a requirement to sense the presence of AC voltage, that could vary from 17 V to 230 V, and trigger a TLPxxx series optocoupler.
The wide voltage range poses a problem in the choice of a ...
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Looking for a large capacitive touch array controller
I'm building a capacitive touch panel.
It has an odd shape, so I resulted to building my own with the capacitive diamond array solution.
It doesn't have a screen underneath, so it's all contained on a ...
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IR laser detection
I'm currently trying to characterise a NIR 940nm laser device that I have recently made. The main thing I want to achieve is to see if the laser is truly doing what the enable signal told it to.
I ...
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Skills to build an airborne radar [closed]
I am currently working on a project to develop an airborne ground penetrating radar - a payload to be put on a drone - we are aiming to develop a synthetic aperture ground penetrating radar of this ...
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How do I best protect a PLC and power supplies from voltage and current spikes coming from actuated components?
Problem
My PLC is getting voltage spikes in the onboard ADC readings when I turn on actuated components elsewhere in my electrical system. I need to protect my PLC from these spikes because they ...
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Which characteristic of an interface allows an ultrasonic sensor to work?
Say I have two liquids in a vat and I want to use ultrasonic to determine what height the interface between the two liquids is. What is the actual liquid property that causes the sound waves to ...
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Detecting presence of mains voltage using Microcontroller, low power solution
I'm currently designing a 'smart' light switch, controllable from Microcontroller and physical switch. I am looking for a low power solution to convert signal so that the Microcontroller can detect if ...
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Help understanding Sampling rate, ODR and oversampling of BMP390
I'm trying to understand how fast I can measure pressure changes with the Bosch BMP390 sensor, but there are a few parameters in the datasheet that are confusing me and I would like to understand how ...
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**FINAL UPDATE** I'm getting closer to a workable circuit for this device?
FINAL UPDATE
I think the power supply is squared away accept for some caps and resistors. Thank you for sticking with me. One question:
There are two thermistors (one for each battery pack) that are ...
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High voltage sensing - voltage to current converter
Hi i need to sense the voltage of a floating load anbd TI suggest placing a sort of common emitter amplifier as shown below:
however im not sure how they calculate the sense voltage:
How is the ...
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Op-amp use in voltage sensing
For voltage sensing, we use a resistor divider and then we always feed that value of the resistor divider to an op-amp and then the op-amp output is fed to a microcontroller.
What exactly does the op-...
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How does this capacitance measurement op-amp circuit work?
I'm studying this scientific paper where a capacitance measurement is done with the circuit shown at page 3. For simplicity I reported it here:
A sinusoidal signal is applied at the input through a ...
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313
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What is a feasible way to measure water level in a pool skimmer?
I need to implement a wireless autofill system for a pool. The skimmer is the only place that I can install the sensor (nine inches in diameter, made of ABS). When the pool is full it is 2" from ...
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228
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Automatic Power Switching (USB-C and AA batteries )
I am trying to use a P-Channel MOSFET to automatically switch from battery power (4xAA) to USB-C power (5V) when the USB-C cable is connected. I am using a resistor network (R1 and R2) to create a ...
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157
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Sensing a 24 V AC signal
I have a sprinkler controller with no separate output for a pump relay. I need a 16-input logic OR circuit that can trigger the relay when one or more of its 16 channels is live with 24 - 30 V AC. One ...
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Find out value of pF capacitors
I'm looking for a way to calculate value of capacitors of picofarad (pF) range. The thing is when I use a RLC meter, it looks like the device is limited to high ranges of pF to nF and so I can not ...
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Potential problems when using a high resistance voltage-divider
I want to design a circuit, that allows me to measure the voltage across a piezoelectric transducer.
The transducer itself has an impedance |Z| of 500 Ohms up to ~20 kOhms.
The voltage to measure ...
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402
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How do self capacitance touch screens work?
I get how mutual capacitance touch screens work, by changing the dielectric around the pairs of electrode and "stealing" electric field lines. Connection to earth of the object (a finger ...
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How does a CAT 4 radio detector work in passive mode?
According to
https://www.radiodetection.com/sites/default/files/Theory-Buried-pipe-manual-V10.pdf
in passive mode a CAT 4 radio detector 'looks' for harmonics produced on the 50/60Hz mains buried ...
user132893
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Interface to sense 5kV through microcontroller GPIO
I want to sense the DC voltage of a capacitor from 0V to 5kV. I need to sense that with a standard 5V powered microcontroller GPIO. I need that the solution doesn't dissipate too much heat and it must ...
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MPPT solar buck charger - how does it sense when to change charge stage/regime
I have a well-engineered MPPT buck solar charger that I am looking to repair; the schematic is unavailable.
The charger is unstable, and randomly changes what charge regime it's in.
Does anyone know (...
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211
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Measuring BLDC motor resistance during operation
Question
Is it possible to sense the resistance of a hobby BLDC motor during operation?
I should clarify that I'm trying to quantify how resistance increases due to thermal effects under load. Thus, I ...
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Why MELF resistor for dc bus sensing
For sensing the DC bus voltage of SMPS, MELF resistors are usually chosen over typical chip resistors (as in this question).
Why is that?
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Are 4N35 optocouplers clamped at 22V?
I am trying to detect mains with an ESP32, for that I started testing this circuit:
I bought a 4N35 optocoupler and 110kΩ resistors.
My first test was using 2 resistors in series, so R1 = 220kΩ.
The ...
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Problem with Interfacing of Multiple I2C Sensors
Problem Description
I'm working on a project involving multiple Proximity sensors (AdaFruit VCNL4040). There are 8 such sensors interfaced through a I2C multiplexer (NXP PCA9547). Additionally I need ...
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Spectrum Sensing
I am trying to find the maximum range of a directional antenna whose beamwidth can be varied. The goal is to understand if a particular (x,y) user lies within the antenna. The distance between the ...
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How to detect which pins on a pin display are touched using capacitive sensing
I'm working on a project to apply touch sensitivity to a modified pin display (30x30). The goal is to allow someone to interact with the display through their fingers and ideally touch.
We initially ...
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601
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4N35 opto isolator with ESP32
I had an old Arduino setup where I used this chip to interface with another circuit which had some LEDs. The goal of the project was to signal the Arduino if the external circuit turned an LED on.
In ...
user106458
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Microwave detection circuit verification
I want to develop a circuit which can detect electromagnetic waves (radio wave, microwaves.)
This circuit will just act as a tamper detect and not physically measure/compute the radiation.
I have ...
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Detecting chess pieces on the board
First of all, I have absolutely no experience in electrical engineering, so bear with me.
I want to build a chess set in which it can recognize what piece is on which square. Initially, I thought I ...
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Verifying electric brake current with opto-isolated feedback
I would like to find a way to sense (or detect) current through an opto-coupler.
This opto is used to power an electromagnetic brake, but depending on the type of brake the current through it can ...
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Switched Mono jack + battery: Make circuit when plugged in
I would like to replicate the functionality inside the Ampoids guitar amp (9v battery) in which the circuit is turned on only when you plugin a male 6.3mm mono jack to it
I believe that the most ...
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138
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Could a time-domain reflectometer, with no access to earth-ground, indicate if a long-wire is attached to the end of a long steel beam?
Without using any other wiring, optics, RF, sound, or vibration, I need to know if a 100 meter length of electrical wire is attached to the end of a 50 meter long steel beam.
I only have physical ...
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Isolated AC line voltage monitoring circuit
I found this https://www.edn.com/isolated-circuit-monitors-ac-line/ circuit in my quest for a low cost isolated AC line voltage monitor and constructed it.
On testing however, I am not getting the ...
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Creating battery pack with biased thermistor resistor network. How to ground if sensing externally
I designed a battery pack board for a customer that uses a multi-cell low-side (NMOS) protection IC. The protection includes OV, UV, OC, and OT/UT protection for the pack. The Overtemp and Undertemp ...
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273
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Reading data from PCB using LED light
I have a PCB that controls some doors and gates at a facility. I need to determine the status of said doors/gates. There are no I/O ports at the PCB to read from, and soldering some probes to it is ...
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What are the two sensors doing in the automatic bread production line? [closed]
I want to know what is the name of these 2 sensors and what function they perform
Some of you were complaining about the picture quality. It is the highest quality image I can get. Also these sensors ...
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Power supply sensing circuit/Mosfet
I am with EE background and recently I had question in interview regarding “How to sense/know when device needs power?”.
So, basically I had a good interview on different topics and one of them was ...
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Has someone here ever made a DIY LiDar from scratch that can 3D scan? If yes, can you give an explanation regarding the process of doing so? [closed]
We've been tasked to create a LiDar system from scratch (we're not allowed to use modules like TFMini and vl53l0x, we have to make it from scratch) that can output 3D projections. So far we've been ...
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Predicting and Evaluating Connector Performance in a Capacitive Sensing Application
I have built a capacitance measuring system using the Texas Instruments FDC2214EVM evaluation module. The system is used to monitor the location of the user's hand in an enclosed space, where ...
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Chosing microcontroller for a sensing project
I am upon chosing a microcontroller for a PCB board project. MCU collects data from capacitance to digital converter (from a capacitance sensor) via I2C and I would like to pass that data to a host PC ...
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termination of a parallel wire differential transmission line as delay line on variable dielectric constant medium
Well this has quite a long title, lets explain the situation
I'm currently working on the design of a sensor to measure the dielectric permittivity of a liquid medium, the idea is to use a ring ...
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HCPL3700 - 220V sensing circuit
I want to use HCPL3700 optocoupler for sensing 220V (line).
I design a circuit but I want to ask some questions.
HCPL3700 is an open-collector output so I pull-up Vout. In AC voltage sensing some ...
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Detect 230 volt main supply in a cheap and easy way
I need to detect by if one o more pumps are really connected to the 230 Volt main supply. Each pumps is activated by means of a triac isolated by a MOC3021. Arduino commands the optoisolators and I ...
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Cheap soldering flux causing QRE1113 circuit not working
Edit (months later): Coming across this silly question I posted months ago, I want to talk about what caused my problem actually. My cheap soldering flux did that. After being heated up, it would flow ...
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How are individual mutual capacitance signal read out from a touch screen?
If I understand this correctly, on a touch screen, you have a a grid based system where the rows and columns are either driving or receiving. When you touch the screen a mutual capacitance arises ...
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