Questions tagged [sensing]

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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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26 views

Sense capacitive change then apply high voltage

When an insect touches two of my wires the capacitance between them changes. This can be detected. Now after a change is detected i want to put high voltage on those two lines. I am afraid however ...
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1answer
42 views

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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2answers
85 views

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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16 views

Error % for readings of average-sensing multimeters

Question: What is the error % in reading the voltage of a Square wave (1 Vpp) with an average-sensing multimeter with a half-wave rectifier, compared to a TRms multimeter The answer seems to be 11.1% ...
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26 views

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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2answers
474 views

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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4answers
187 views

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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1answer
105 views

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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1answer
27 views

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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1answer
104 views

Check for live high voltage shielded three phase conductor

We would like to know if a shielded high voltage cable 8000V AC, 3 phases, is "live". Whether there is current flowing or not. Ideally we design a little device that's strapped around the cable (...
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2answers
169 views

Why I got a minus output value?

When I simulate the circuit on (OrCad) I got an output voltage between (0 to 1) V changing with temperature . but when I connect the circuit I got the output voltage = -1.85 in minus and different ...
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2answers
160 views

Controlling an output based on level of AC signal

This is my first post on this StackExchange after years of lurking, so please be gentle! I would like to be able to enable an output (for example an LED) based upon an AC voltage from a split-core ...
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2answers
257 views

Differential Opamp Strange Behavior

I have no answer for this strange opamp behavior. The circuit shown is from a typical nonisolated ,Non grid-tie inverter product (imagine H bridge Inverter). which has a common -ve high power circuit ...
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1answer
202 views

Sense 230V - current

Brief sum up (you can go directly to the end if you already read the sum up in the other question) For a home project I'm making a controller to drive a two-direction 230V motor. For those unfamiliar ...
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1answer
205 views

Sense 230V - voltage

Brief sum up (you can go directly to the end if you already read the sum up in the other question) For a home project I'm making a controller to drive a two-direction 230V motor. For those unfamiliar ...
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3answers
148 views

Automotive accelerometer calibration

I would like to design a device which measures acceleration, yaw, pitch and roll for motorsport/automotive application. I plan on using an analog accelerometer, to provide better bandwidth and low ...
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1answer
36 views

Is there such thing as an EMG sensor which doesn't use electrodes?

In a traditional EMG the user is required to clean the target area with alcohol, then apply some gel, and finally stick on an electrode. I'm looking for some sensor that can read the same muscle ...
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1answer
11k views

AC Optocoupler for 230V line detection

I am trying to detect line voltage (230V AC, if the supply is ON/OFF) by a microcontroller with the help of an AC optocoupler. The optocouplers I have evaluated are PC814, H11AA1 and SFH620A-3, out of ...
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2answers
764 views

220 VAC detection using Optocoupler

I tried to detect 220V AC in my microcontroller using SFH620A-3 with series resistance of 440K (2 x 220K, 1/4 watts SMD type), a 1uF at the output to smoothen the pulse and every works as expected. ...
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0answers
106 views

MOV wear sensing

How would one go about to implement accurate sensing of metal oxide varistor wear level? Even cheapo surge protects come with a LED to indicate protection status, but I presume this is not based on ...
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5answers
552 views

Isolated mains sensor

I’m building a mains sensor that should be able to operate safely at a voltage of up to 650VAC. I’ve already built one before, that operated with 130VAC, which I successfully monitored with a MCU, and ...
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1answer
497 views

Ion-current sensing in ignition coils

Variety of IC engine manufacturers have eliminated acoustic knock sensors from recent designs. Those got replaced with Ion current sensing circuitry (feedback from the spark-plug). In parallel, SMART ...
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1answer
107 views

Positive and Negative Sense Circuit. How/why does this work?

I am trying to build a centre-off model railway controller, no reversing switch. I am working on the overload/short detection part of the circuit based on sensing the voltage across a 0R68 resistor. I ...
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2answers
161 views

vibration sensing circuit doing so great

I have attempted this diagram from here: with one modification - instead of the 4093 circuit ( comparator+inverter+hysteresis gates) I have used a HC14 (inverter+hysteresis gates). Can this be why i ...
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5answers
3k views

What is purpose of an Undervoltage Sensing Circuit?

I am wondering what is the purpose of an IC such as the MC34064. Is it just to ensure a reset of microcontrollers upon power up or are there other reasons? I used to make a simple transistor switching ...
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3answers
2k views

Alternatives for EMG muscle sensors?

I would like to measure muscle tension with a sensor. When I'm sleeping sometimes a shoulder muscle cramps and I would like to make something (for example with an Arduino board) to wake me up. The ...
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5answers
1k views

How to improve resolution and presicion of sensor reading?

I'm trying to measure temperature with an arduino uno and a LM335 temperature sensor. The LM335 can provide differences in temperature between -40C to 100 with a resolution of 10mV. I read the sensor ...
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132 views

Sensing AC voltage

In a project I'm working on (Totem pole PFC) I need to sense the input AC voltage, scale it down, rectifing it/adding an offset and then send to the ADC of the digital controller to use in the control ...
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2answers
2k views

AC voltage sensing circuit

In a project I'm working on, I am designing a Totem pole PFC, and for the controller (using a digital controller) I need to sens the input voltage, which is an ACvoltage and feed it to the ADC of the ...
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6answers
10k views

What makes smartphones tilt-sensitive? Will they retain this ability in zero-gravity conditions?

Most smartphones are tilt-sensitive, but what device makes this possible? Additionally, how does it (and the sensors associated with it) work? Also, since the working of these sensors seem, almost ...
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1answer
198 views

Sensing high differential voltages using operational amplifiers

Is there any solution to sense high differential voltages using operational amplifiers (without using resistive voltage divider) ? The input voltage range is [-30, 80] Volts. I've searched on all ...
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1answer
424 views

Metal detecting using a small inductance

I have a coil with approximate indutance of 15uH used to detect metal through changes in inductance. I want to use an op amp or 555 to oscillate with frequency based on the inductance. However this ...
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1answer
51 views

Harmonic compensation due to a non-linear load

I am doing a project on harmonic compensation due to non linear loads. My current at the source is non-sinusoidal due to non linear load. The current contains harmonics and i am using ACS712 current ...
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2answers
1k views

How does this capacitive soil moisture sensor work?

I’m trying to figure out how the following soil moisture sensor works. It’s obviously a capacitive sensor where the capacitance changes when the soil moisture varies. However, as you can see, the ...
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3answers
212 views

current sensing board/adapter (low current)

I'm trying to find a well designed current sensing board which is intended to be used with an oscilloscope. The closest thing i found is the ucurrent which is meant for multimeters, low cost ...
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1answer
471 views

Do current / power monitoring ICs (e.g. INA219) allow frequent re-reading?

I'm looking at the datasheet for the Texas Instruments INA219 and on page 20 it shows a table for "Shunt ADC Resolution/Averaging", which describes the ADC resolution and averaging settings which can ...
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2answers
279 views

How to display voltage on OLED? [closed]

The basic idea is to make an OLED voltage meter. I idealy want to use as little parts as possible. If my understanding is correct I would need a voltage sensing circuit which would give feedback to a ...
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3answers
84 views

Sensor to rapidly sample light intensity of a small area at a distance?

I'm looking for a sensor or method of rapidly sensing light intensity of a 1-inch x 1-inch square of a LCD monitor at a distance of 1-1.5 feet away. Does anyone know if such a thing exists, or has ...
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3answers
74 views

How can i sense if a circuit is open on 2 wires and if so, close the circuit on another 2 wires?

I have a 4 wheeler that i converted from a mechanical locking differential to an electric one. the mechanical one had a 2 wire spring loaded switch that as the mechanism rotated it pushed the pin in ...
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4answers
2k views

Flame sensing using Flame Rod and Short circuit identifying

I am sensing a flame using a flame rod. I am using 12V AC at the input and at the output flame sensing circuit which is made of opamp, some resistors and capacitors, I get 1.6-2.4V when there is a ...
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2answers
469 views

Measuring a potentiometer with noisy power

I need to measure a potentiometer where the voltage supplied is very noisy and cannot be filtered. I run into this a lot in my work, but currently I'm trying to measure a steering angle potentiometer ...
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1answer
627 views

Detecting motor stall with lm311

I have 9v DC motor that I want to use to lock a door. Control is achieved using an esp8266 board. The esp8266 also switches the direction of rotation via an H bridge. So far, so good.. Now I want to ...
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2answers
70 views

Measure current in power suppy [closed]

I have a power supply which I ordered online for 100 amps. I thought it will be digital but its an old fashioned type. I want to build the current sensing circuit to find out how much current is ...
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2answers
1k views

Capacitive touch insulation problem?

I have an "U" shaped metal profile that is 2 meters long each side is 1.5 cm. It is sprayed with acrilic color. and i want to use it as indirect light profile/enclosure for a 12v Led strip. While ...
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2answers
685 views

Determining the radius/length of an IMU on a rotating stick [closed]

So I can't really wrap my head around this problem. I have an Inertial Measurement Unit (IMU consisting of an accelerometer and a gyroscope) mounted to a stick which can rotate from a fixed position ...
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1answer
85 views

C4D capacitively coupled electrode sensing - circuit simplification

I am trying to make a detector to pick up small changes in capacitance. Basically both electrodes have a common ground and are closely spaced. One is driven by oscillator at 0.1-1MHz and the other one ...
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1answer
2k views

Is it possible to “trace” a hall effect sensor on a PCB?

To my knowledge, a hall effect sensor is just a soft-cored hooped metal (iron?) with some wire wrapped around it a precise number of turns. This surrounds another wire that you wish to measure the ...
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1answer
1k views

Voltage sensing using Arduino with and without common reference

I wish to make a voltage sensing circuit (range -15V to +15V) using an Arduino's ADC. The problem is that since this circuit will be part of a much larger circuit in which the Arduino is performing ...
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3answers
502 views

Sensing power supply - sensing after the on/off switch

I have a sensing power supply powering a custom build LED light for video. There is an on/off switch after the sensing lines and everything works well. The setup looks like this: However I'd like to ...