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Questions tagged [sensing]

Related to sensors and sensor systems

0
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2answers
46 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 ...
3
votes
4answers
139 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 ...
0
votes
1answer
43 views

QRE1113 stopped working shortly after powering up

recently I made a prototype IR tracking board by referring SparkFun Line Sensor Breakout and here is pictures of the PCB. (The three in the middle was not soldered because I want to see if they could ...
0
votes
0answers
19 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 ...
0
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0answers
51 views

Current Sensing circuit solution

I need a current sensing circuit solution for my application. I have a power board which has 5v line and 24v line. Each lines are going to two different loads. In load 1 which has 5v input i have an ...
1
vote
1answer
38 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 (...
0
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2answers
108 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 ...
0
votes
2answers
96 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 ...
0
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2answers
173 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 ...
0
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0answers
28 views

Lowest resistor value for enclosed light sensor unit with nearby lighting without losing sensitivity

This is a drawing I made of a light sensor unit I'm creating. Inside of it, I have a circuit board containing 3 7-segment displays and I have two photo-transistors (yellow half-circles in the picture) ...
1
vote
1answer
102 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 ...
0
votes
1answer
120 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 ...
0
votes
3answers
69 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 ...
1
vote
1answer
35 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 ...
0
votes
1answer
4k 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 ...
0
votes
2answers
356 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. ...
1
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0answers
79 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 ...
0
votes
5answers
330 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 ...
0
votes
1answer
324 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 ...
1
vote
1answer
88 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 ...
0
votes
2answers
99 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 ...
11
votes
5answers
2k 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 ...
2
votes
3answers
1k 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 ...
0
votes
5answers
823 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 ...
0
votes
0answers
101 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 ...
0
votes
2answers
1k 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 ...
61
votes
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 ...
1
vote
1answer
91 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 ...
1
vote
1answer
334 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 ...
1
vote
1answer
45 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 ...
1
vote
2answers
930 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 ...
-1
votes
3answers
171 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 ...
4
votes
1answer
384 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 ...
0
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2answers
255 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 ...
2
votes
3answers
83 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 ...
0
votes
3answers
73 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 ...
0
votes
4answers
1k 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 ...
1
vote
2answers
401 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 ...
1
vote
1answer
484 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 ...
-2
votes
2answers
67 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 ...
1
vote
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 ...
1
vote
2answers
557 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 ...
0
votes
1answer
79 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 ...
6
votes
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 ...
0
votes
1answer
809 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 ...
1
vote
3answers
412 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 ...
1
vote
1answer
483 views

Current sensing with AD623

I want to measure current that flows from a several kΩ load with source voltage sweeps from 0-200V. I want to measure possible energy losses, so I need both low and high side sensing. Setup is ...
3
votes
2answers
2k views

Choosing a Shunt Resistor for Low Current Applications

Is it possible to use a shunt monitor to measure current for low values(10 mA-100mA) and if is it possible, should I use low resistive values like in most of the power circuit applications? I know ...
0
votes
2answers
2k views

Detect if input voltage is 110V or 230V signal

I'm building a small electronic project that will measure the power consumption of a device and send this back to Arduino or ESP2866. I've figured out how to measure the current that goes trough a ...
0
votes
1answer
231 views

Lm35 arduino and battery

I am doing a project where I need to measure temperature using lm35. I am using arduino's analog A0 to measure, I light up extra LED on an other pin while measuring. Suddenly the alarm triggers. I ...