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Questions tagged [detector]

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2
votes
2answers
117 views

Bandpass Filter: Single supply op amp design

I have taken on a hobby project and I am trying to make a circuit which would be able to identify an acoustic signal with a frequency of 40kHz. Here is the circuit of a band pass filter for this: ...
0
votes
0answers
67 views

Evolving a very simple E-field detector

I'm looking into non-contact solutions for detecting charge (even through certain casings) in passive components. This circuit: is from this site, it works and I've experimenting with a go/no-go ...
-1
votes
1answer
53 views

My mobile detector circuit won't work

I'm trying to get C3 to detect RF signals from a mobile phone. Amplify this signal to detect it using an LED. My main issue is simulating the antenna on multisim since multisim doesnt have an antenna!...
0
votes
1answer
69 views

Electronic detector to measure of distance? [closed]

I am not well known about electronic and it is my first question here, beforehand sorry for not qualified question. Let me try to explain what I am looking for: Is there chip or any another ...
2
votes
2answers
82 views

Is there a simple way to detect which connector is powered?

I have a circuit with two power connectors, J1 and J2. I would like to be able to detect which one the power is coming from. The trick is that the connectors need to provide power to each other. ...
1
vote
0answers
1k views

Metal Detector using IC 555 Timer project

I want to build some project about metal detector using integrated circuit 555 timer. I already made a schematic in proteus 8 application. I made some change with the original schematic i found on ...
1
vote
1answer
126 views

How to calculate noise power (dBm) of a photodiode?

I want to check the thermal noise spectrum of a photodiode (PD) at different frequency response but I do not know how to calculate it. Below graph is an example which shows noise power (dBm) as a ...
0
votes
2answers
266 views

Non contact (contactless) AC or DC detection?

I'd like to detect AC or DC current (not the current level just nothing or something => ON/OFF) in a wire with a (DIY) sensor just in contact (glued) with the wire plastic insulator. At the end the ...
-3
votes
4answers
168 views

How do I reverse-bias a resistor?

We all know that a photo diode can be used as a light detector and as a light emitter (although the way that it's built will usually make it specialized to prioritize one application over the other); ...
0
votes
0answers
51 views

Detecting ultrasonic by microphone and MCU

I design data-over-audio transmission to MCU. To do it i need ultrasonic detector with specific frequency, for example 50kHz. Seems, that electret microphone+low-pass filter+envelope detector will ...
1
vote
2answers
106 views

Flatness vs Frequency parameter in RF zero bias detectors

I require the measurement of RF power from a port, and I am considering using a zero-bias RF detector in order the measure the power being delivered through the port. These devices give a voltage ...
0
votes
1answer
118 views

What is the difference CMOS and CCD image sensors? In terms of Infrared spectrum [closed]

What is the difference between CMOS and CCD image sensor arrays? i.e working principles. Please consider in infrared spectrum. Which one's fabrication is expensive/ or cheap ? Which one gives ...
4
votes
5answers
591 views

Tri-State Detection

Some of you may have read my answer here to detect when two digital signals are either high or low, i.e. not both tri-state. One method uses window comparators the other opto-couplers to detect when ...
0
votes
0answers
416 views

Optical Smoke Detector design with Arduino: buzzer problem

I'm working on an Optical Smoke Detector using Arduino UNO board. Here is the circuit diagram: Whenever smoke is detected by the smoke sensor, the buzzer and LED should work. From the Arduino ...
0
votes
2answers
224 views

Envelope detector and DC voltage

I am currently working in the simulation of a physics project. One of the detectors inputs a voltage V1: V1(t)= D+Acos(wt) and tries to extract the amplitude. I read that a simple Envelope detector ...
0
votes
3answers
144 views

Peak detector circuit operation

So I understand that the capacitor charges up to the peak voltage and remains there since it cannot discharge due to the diode. But when I reduce the voltage on the input, the capacitor voltage also ...
5
votes
2answers
1k views

Why does this CO detector forbid the use of lithium batteries?

I have several Kidde KN-COB-LP2 CO detectors installed in my house. They look like this: They operate on standard AA-size alkaline batteries, and typically last several years on such batteries. The ...
-1
votes
2answers
273 views

Gap detector does not register high speed projectiles

I'm trying to build a gap detector-based ASG gun chrono. I successfully connected two gap detectors to Arduino Uno, wrote a program, which measures time between two voltage spikes (on each gap ...
3
votes
1answer
1k views

Light intensity and photodiode current

Recently i am using a LED as a photo detector . Follow by this instruction : http://makezine.com/projects/make-36-boards/how-to-use-leds-to-detect-light/ An opamp is used to convert the photocurrent ...
0
votes
1answer
442 views

detector in logic gate design

1.regarding to logic gate concept i have to design the circuit with 4 bits multiple of 3 detector. but when i trying to make logic gate and truth table it seems to me it's wrong so i have no idea ...
1
vote
1answer
279 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 ...
3
votes
5answers
544 views

Measuring relative rf signal strength [closed]

I'm trying to measure the relative signal strength received by a dipole antenna for orientation purposes. I'd like to do so using an ordinary multi-meter. I don't know much about RF circuits, but ...
2
votes
1answer
160 views

Building an inverted peak voltage detector

So I am trying to build a detector that will find the lowest voltage dip of a DC source. So for example, if I attach a load I can see what the voltage drops to. I have built this peak detector in ...
0
votes
0answers
56 views

Build a breathalyzer like device but for testing liquid or semi-liquid subtances

As a recovering alcoholic, I know for a scientific fact that alcohol will altogether evaporate from boiling water after sufficient time, and nearly all alcohol from boiling food, which would have a ...
1
vote
1answer
77 views

Why do some TSOP1738 have a metal cross over their window?

Why do some TSOP1738 have a metal cross over their optical window while some do not have this cover? Does not it obscure the view and shorten the range of the sensor? Does it have some positive ...
1
vote
1answer
464 views

Induction loop detector

I am trying to create an induction loop detector by following this http://www.allaboutcircuits.com/projects/metal-detector-with-arduino/ but apparently something is wrong on my side or I missed ...
0
votes
1answer
71 views

How do I build a micro controller based laser detector

I want to build a laser detector using a photoresistor and a pen laser. Ideally, I would like to increase the surface area that detects the laser beam, perhaps through refraction or diffusion. I'm ...
4
votes
3answers
5k views

Conversion from dBm to Volt/ meter

I have no experience with electronics but I have a question. Actually I'm using a circuit for a project that is able to measure RF power at its input in dBm; the circuit provides the integration of a ...
1
vote
2answers
1k views

Does a simple bug detector detect electric field or magnetic field?

Hi. This is a very cheap and simple bug detector that is supposed to make sound when it detect RF signals between 100Mhz-2600Mhz. I found out that it doesn't do what it supposed to do,since its ...
0
votes
1answer
90 views

Understanding resonance detectors

I'm exploring an old device that detects RF frequency. It has a generator of bipolar spike pulses +-1V interleaved by 0V sections, diodes and antennae (L1). simulate this circuit – Schematic ...
0
votes
1answer
84 views

How to detect/monitor AC power

I'm attempting to build a system to help my Father-in-law monitor the power to his house. Here's the details of his problem: He lives in the woods where power is somewhat unreliable so he has a whole ...
1
vote
2answers
1k views

Falling and Rasing Edge Detector

I will use a motor adapter in my design.This motor adapter doesn't have a spice model. Therofore I will design inside structure of this adapter. In this motor adapter has a delay and xor gate part.I ...
3
votes
1answer
239 views

High voltage led detector

I need a circuit to indicate if the DC voltage across two points is exceeded a certain High value (350 V) by using LED as an indicator. For example if the voltage is 355 V then the LED will light,but ...
1
vote
0answers
264 views

Dark detector with 555 timer and output pin has a LED

I am a complete novice and I had done it in a hurry with my kiddo around. I have redrawn it, with the values I used. The circuit works. Also between pins 6 and 7, if I use a 100 K/10 K it works. ...
1
vote
4answers
1k views

High Frequency (16 Mhz-48 MHz) Peak Hold/Envelope Detector Circuit?

I'm trying to make a peak hold circuit for a very high frequency bandpass filter that needs to be able to operate at 16 Mhz, 40 Mhz, and 48 Mhz. I've singled out the peak hold part of my overall ...
2
votes
2answers
2k views

How exactly do I null my metal detector coils?

I've finally started work on my metal detector project and after a fair start, I'm a bit stuck. The circuit is based almost entirely on the buccaneer VLF circuit to be found here. I've made some ...
0
votes
2answers
643 views

how to improve RF meter? [closed]

On https://www.rfsafe.com/product/diy-rf-meter-led-powered-rf-detector-diodes/ , there is a kit which contains: nine 1SS86 Schottky diodes and one LED, which uses to detect mobile phone and ...
0
votes
0answers
624 views

Field strength meter for WiFi/Bluetooth

I'm a student in Computer Science and I'm sorry about the question; I don't have much experience with the design of electrical circuits. I'd like to make a field strength meter using an Arduino board,...
0
votes
1answer
344 views

Pspice simulation ERROR

I am trying to simulate this Photoplethysmography circuit in Pspice.But I am getting the following errors: ERROR -- Convergence problem in transient analysis at Time = .193 Time step = 296....
2
votes
5answers
4k views

convert falling / rising edge to pulses with minimal components

I have a signal that changes from high state to low every few minutes, after changing state it will remain constant, all level changes are clean. I'm looking for the smallest possible circuit that ...
0
votes
3answers
554 views

How To Detect a Gunshot

Hey everyone I am working on a project that is a lot harder than what I thought. It is a project for school. How can I detect a gunshot indoors without using an array of microphones? I had something ...
0
votes
1answer
698 views

When wiring IR Phototransistor, why is a pulldown resistor needed?

My phototransistor looks like the one here, wired like this: I don't know the exact model or anything like that. It came in an Arduino kit and was labeled "flame sensor". I used an arduino to connect ...
1
vote
0answers
100 views

Strange behavior from peak detector's certain op-amps

I built a multiple feedback 2kHz band-pass filter with gain Vo/Vi = 4 and an envelope detector for this filter as shown in this great video tutorial EEVblog #490 - Peak Detector Circuit When i ...
0
votes
4answers
879 views

Detecting object passing through gateway

Hoping this is the right place for this. Honestly not even sure what to call it. Essentially I need to find a way to detect an object flying through a physical portal/gateway/doorway. I do not care ...
1
vote
2answers
894 views

Envelope detector

I would like to have the envelope from a signal using a simple circuit composed of a diode and a low pass filter. I know : *Tam > t >> Tcarrier *The diode must be a germanium diode because of the ...
1
vote
1answer
465 views

RFID chessboard

I want to make a electronic chessboard that detects the position of every piece on the chessboard. So I did some research, and one way would be to put RFID tags under every chess piece. Each tag ...
0
votes
1answer
364 views

Beacon detector using microcontroller and BLE

I am looking for BLE device which can detect ibeacon or beacon module/tag. I am interested to use microcontroller with BLE module instead of smartphone for beacon detector. Can any one suggest where ...
1
vote
1answer
185 views

Mobile Phone Signal Flash Light 3-12V - not working. Circuit viable?

Another ebay-heist that does not work as adverstised. I build it, and tested with some normal g3 cellphones, but no dice. My antenna at J2 is an 8cm long wire (not really lambda/4 of anything, but i ...
-7
votes
2answers
183 views

Need Help regarding this Peak to Peak Detector Circuit [closed]

Hey guys need some help from you... I have made a small circuit (Peak to Peak Detector Circuit). but i am confused what should be the voltage ratings of the capacitors and wattage ratings of the ...
1
vote
1answer
88 views

About the combination of two signals with capacitors

Here is a link of an article I've been reading. http://www.analoguehaven.com/moog/thereminblack/hotrod.pdf In page 4 there is a circuit schematic. Notice there is a part called variable pitch ...