Questions tagged [detector]

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2answers
81 views

Switch off power when 0v is sensed / Short to ground

I have already posted this question but I made a mess of the diagram so deleted it and am posting again, apologies to anyone to answered the original question. I'm fairly new to electronics and am ...
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2answers
80 views

How would i go about detecting if a rs-485 cable is plugged in?

The basic problem were trying to solve is certain secondary device's cables gets left unplugged and we need a way to detect a cable that is plugged into my device,and check if that cable is actually ...
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0answers
36 views

Transformer-insulated flame ionization detector. How to improve response? Triode, messure current safety, ignition fires

I am trying to do a isolate flame ionization detector with a transformer ignition. But, when I put it on the frame, nothing change.. (0.2VAC) I put a amplifier (10 teraohms impedance) to read the ...
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2answers
83 views

Use of ceramic capacitors in HV system

When I opened the supply board to the detector (Geiger counter,) I got the above circuit. The detector uses a gas-filled tube with a central wire at high voltage to collect the ionization (charge) ...
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2answers
74 views

Sequence Detector forced to wait a specific number of bits

So I have this little problem, where I am supposed to build a sequence detector which is forced to wait a specific number of bits before going into the reset state. It's kind of like pin codes work. ...
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3answers
171 views

Most simple way to detect small voltage changes(~150mV)

I have one unit of museum cabinet detector that works on 18v. I want make simple security circuit with detector. I've figured out that two output ports on detector are normally contact(NC), but it'll ...
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1answer
62 views

Defect LED detection for car lights

The schematic beneath is a new project of me. The theory behind this is: My car has a very fool proof bulb failure detection and warning system. CANbus proof LED bulbs can't fool the car and just a ...
3
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1answer
61 views

Noise in crystal detectors (historical)

I'm reading over the history of British WWII radar systems, and one thing that really struck me was the improvement in crystal detectors. The were a vital component of microwave radars, and while the ...
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0answers
45 views

How to calculate the ripple voltage of the output in the attached circuit?

In the attached drawing, I know the discharge constant time is RC=2ms, which is very close to the input signal cycle time T=1/400=2.5ms. I am trying to derive the ripple voltage through the attached ...
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2answers
99 views

How inductance of a coil changes when there is a metal object nearby?

I am not sure if it is increasing or decreasing as some sources say it is increasing whereas some say it is not. What actually happens when a metallic object is put under a coil that is meant to be ...
0
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1answer
55 views

NC Opening Contact detector to drive a NO relay Contact circuit

I'm looking for a simple +5.5vdc powered circuit (perhaps a PNP transistor driving a NO Reed Relay coil?) - I need a circuit that can detect when a pair of Normally Closed contacts with no voltage ...
0
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1answer
31 views

Motion Detector Time Adjustment

What it means when adjustment area is: 10±5 s-10min? I cannot find a solution from Google.
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2answers
92 views

Automotive tachometer signal interpretation

I'm trying to build a custom dashboard for a car (Daewoo Lanos 1998 with Delco ECU). Tachometer signal, that comes to dashboard with a separate wire looks a bit strange to me. It seems that the signal ...
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0answers
82 views

Choosing a suitable PFD for PLL

I'm building a capacitive vibration sensor and it has to reject the stray capacitance by locking the LC oscillator at 64 MHz, where I can demodulate relatively small frequency changes. The best way to ...
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1answer
151 views

LTSpice - envelope detector LPF behaving like buffer

I have an issue with an LTSpice simulation and I'm not sure if the issue lies in the simulation setup or somewhere more basic. The simulation is as follows: The system is as follows: on the left, ...
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1answer
71 views

do is anyway to detect Tablets Pills package is empty or not? [closed]

do infrared sensor can pass through transparent plastic and work?
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0answers
106 views

Understanding the basics of AC coupling

The real case I am working on: I need to connect a CZT (Cadmium-Zinc-Tellurium) detector to a custom ASIC input (a Charge Sensitive Amplifier of which I do not know the input impedance, if that ...
0
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1answer
82 views

Missing pulse detector for low input?

I'm looking to implement a watchdog circuit. Tried the standard "missing pulse detector" schematic such as one from http://www.falstad.com/circuit/e-555missing.html - and it works well when the input ...
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1answer
44 views

Can you convert a headphone into a metal detector coil?

I was wondering if it's possible to convert a stereo headphone into a coil to be used as a signal transmitter and receiver for metal detecting? The idea is to use a smartphone as a signal generator.
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2answers
196 views

Comparator as a current detector

I'm looking for a simple circuit that uses only a comparator (or an opamp) to detect the presence of a small current through a high-side current resistor. The idea is for a microcontroller input to go ...
4
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2answers
94 views

Reducing the range of a D flip-flop frequency detector

I'm designing a frequency tracking circuit and I came up with a circuit that tracks frequencies from Fclk to Fclk/2: However, it would be very nice if the bandwidth was a bit narrower, from Fclk to ...
2
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2answers
113 views

Is it possible to convert the audio signal from a smartphone's headphone jack into radiowaves? [closed]

I was watching a video of someone using his smartphone and a custom designed coil to make a metal detector. The smartphone was connected to the coil via headphone jack. I couldn't understand how he ...
2
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2answers
935 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: ...
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1answer
103 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!
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1answer
92 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
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2answers
136 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. ...
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0answers
3k 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
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1answer
200 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
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2answers
492 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 ...
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3answers
253 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); ...
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0answers
77 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
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2answers
184 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
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1answer
145 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
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5answers
1k 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 ...
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0answers
706 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
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2answers
264 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
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3answers
188 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 ...
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2answers
3k 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 ...
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2answers
374 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 ...
2
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1answer
2k 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
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1answer
554 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
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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 ...
3
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5answers
748 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
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1answer
219 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 ...
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0answers
62 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
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1answer
86 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
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1answer
599 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 ...
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1answer
111 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
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3answers
8k 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
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2answers
2k 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 ...