Showing posts with label detector. Show all posts
Showing posts with label detector. Show all posts
Wednesday, August 14, 2013
Amplitude Average Detector Circuit
This is a design circuit for sensing amplitude. This circuit is similar peak detector. But the output won’t immediately follow the input peaking. Because the output follows the input peak slowly, averaging effect will be seen at the output. This is the figure of the circuit.
This circuit is work based on two IC’s, there are LM307 and LF351. Use 1% resistor for R1, R2, R3, and R4, and you can achieve negative and positive cycle difference of 0.5dB at the worst case. If you use 5% resistors then the difference between positive and negative cycle gain difference would be about 2dB (worst case). The averaging time constant will depend on R5-C2, you can change to other values if needed. [Circuits diagram source: National Semiconductor Application Notes].
Tuesday, March 12, 2013
How to Make a Non Contact AC Mains Phase Detector – Measure AC Field Strength Wirelessly
The circuit discussed in this article is of a non-contact mains AC field detector which displays the presence of a mains AC field from a distance of more an 6 inches. The circuit can be used for locating faults in house wiring without the need of making physical contact with the inner conductor of the wire and becomes useful in locating the breaks in a wire by pin pointing the area where the AC mains may be blocked due to a breakage.
The circuit is basically high gain non inverting amplifier which is configured using a few opamps and a few other inexpensive passive electronic components.
Just a couple of opamps have been incorporated here from the IC 324 for the required operations.
Looking at the figure we notice the following things:
The non-inverting input of the IC is grounded making the sensitivity of the configuration to the maximum.
Similarly a feed back loop created by connecting the output of the opamps to the inverting input helps to increase the gain of the set up many folds.
The input is applied to the inverting input 2 of the IC through a blocking capacitor.
The signals entering via the antenna is quickly picked up by the opamp inverting input and sent to the preceding circuit for the required processing and amplification.
It may be interesting to note that the sensitivity of the design can be simply varied by changing the value of the feedback resistor R1, for maximum sensiticity this resistor can be omitted.
However this can make the circuit a bit unstable and might provide false results.
The next stage includes another identical amplifier which is just the repetition of the previous input stage. This stage has been included in order to make the response of the circuit instant and so that the circuit is able to pick even the slightest of RF or the AC field within a certain range.
In case the circuit is intended to be used for detecting mains phase only at touching proximities, the sensitivity may be reduced to the required levels or the second stage may be excluded from the design.
The LED connected at the output is used for displaying the presence of the AC field; an illuminated LED identifies the presence of the field while no light from it provides the opposite conclusion.
By connecting a 1V FSD moving coil meter at the output, the device can be used to detect and measure the average strength of the AC mains present in that particular vicinity.
Parts List
R1 = 2M2,
R2 = 100K,
R3 = 1K,
C1 = 0.01uF
A1, A2 = IC 324
Sunday, March 10, 2013
How to Make a Ghost Detector Circuit
Do you believe in the existence of ghosts? Well some of you may answer positively while some may just nod their heads showing sheer skepticism regarding the issue. Whatever may be the reactions; nobody just can’t deny or ignore the responses delivered from the circuit explained in this article. Here we are discussing a super simple yet super sensitive paranormal activity sniffer circuit, which can be effectively and possibly used for detecting ghosts or similar supernatural existence within a range of 10 meters. Many of these circuits may be built and posted at definite intervals for securing a certain premise having a large area. The circuit incorporates an alarm at the output which sounds immediately on detecting a paranormal intrusion. The circuit is ideally suited for areas that are prone to ghosts or likely of getting infested with similar para-natural sneakers.
WARNING 1 – THE DEVICE HAS BEEN TESTED WITH POSITIVE RESULTS AND IS PROVED TO BE EXTREMELY ACCURATE WITH THE DISCUSSED DETECTIONS. FOLKS WITH WEAK HEARTS OR TENDER PERSONALITY ARE ADVISED NOT TO GO ABOUT WITH THIS DEVICE, BECAUSE THE DEVICE NOT ONLY DETECTS BUT ALSO COINCIDENTALLY HAS THE ABILITY OF ATTRACTING THE PARABEINGS.
WARNING 2 – THE DEVICE CAN BE TESTED IN MORGUES, GRAVEYARDS, cemeteries etc. ZOMBIES ARE THE ONES WHICH ARE INSTANTLY DETECTED BY THIS DEVICE EVEN FROM DISTANCES MORE THAN 50 METERS. NO DOUBT CREATURE LIKE ZOMBIES WILL HATE THIS DEVICE….BEWARE.
Concept
It has been found through experiments by many researchers that paranormal occupancy is strongly accompanied by RF disturbances ranging from a few Hertz to many Kilohertz.
These signals may be directly proportional to the hostile nature of the ghost. Zombies are found to be emitting the strongest signals and are therefore considered the most horrible among the lot.
The circuit of a ghost detector discussed here is typically configured for capturing the above RF emissions from these creatures and transforming them into more human understandable electronic indications.
Circuit Description
A single versatile IC 324 is involved in the whole operation.
The IC is a quad opamp IC, meaning four opamps in one package.
Referring to the figure, the opamps can be seen configured as hi gain non inverting amplifiers.
All the opamps are configured as high gain signal amplifiers.
Tiny electromagnetic or RF disturbances which are typically found being generated during the presence of ghosts or paranormal activities are instantly picked up by the antenna of the circuit and are fed to the input of the first opamp stage at pin #9.
The signals get instantly amplified and are transferred to the subsequent stages for further amplification and enhancement.
The output of the last opamp is connected to an opto-coupler.
The optocoupler is a homemade type, incorporating an LED and an LDR fixed such that their emitting and detecting surfaces are placed face to face inside a light proof enclosure.
Here, the optocoupler is used for sensing the LED illumination that may occur when a certain paranormal activity is sensed.
The illumination produced over the LED is tracked by the LDR whose resistance falls with the LED light.
The fall in the resistance of the LDR activates the connected transistor at the output, which in turn actuates a buzzer or a horn indicating a possible ghost intrusion.
The whole circuit may be built over a small piece of vero-board and should be strictly operated with a 9 volt battery.
The whole system may be enclosed inside a plastic box with the antenna kept protruding out of the box.
Parts List
R1 = 100K,
R2 = 2M2,
R3, R4 = 1K,
C1 = 0.01uF ceramic
C1 = 0.01uF ceramic
OP1 = LED/LDR assembly inside a light proof enclosure,
T1 = BC557,
B1 = Piezo Electric Buzzer
READERS ARE REQUESTED TO SHARE THEIR EXPERIENCES WITH THIS DEVICE. A PHOTO OR A VIDEO PROOF WILL BE GREATLY APPRECIATED....
READERS ARE REQUESTED TO SHARE THEIR EXPERIENCES WITH THIS DEVICE. A PHOTO OR A VIDEO PROOF WILL BE GREATLY APPRECIATED....
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