Human Sensing Circuits
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D switch S location function. FIG microphone to a speaker on behalf of the (also designed a door using an electret microphone) port channels through C9 send people IC2 amplify .. -
Dctl is a two-stage amplifier, the first stage amplifying transistor VT1 collector voltage U.. -
Diagram 2 shake tube n. Capacitance C. Trigger voltage rectifier filter element. H is a trigger voltage transistor amplifier circuit, three pull tube n, U, v. Composition trigg.. -
The circuit is basically a NE555 monostable, the only major difference being its method of triggering. The trigger input is biased to a high value by the 22 ohm resistor. When the contact plates are touched, the skin resistance of the operator will lower.... -
A 3-x -3-inch piece of circuit board, or similar size metal object which functions as the pick-up sensor, is connected to the gate of Ql. A 100-MD resistor, R2, isolates Ql"s gate from Rl, allowing the input iropedance to remain very high. If a 100MO.... -
The SillOO series circuit input is connected to a capacitive field sensor-possibly a piece of doublesided circuit board. Any induced voltage change on the plate is fed to the input of the peak detector section of the op-amp circuit. The Schmitt trigger.... -
The 4047 is configured as a monostable multivibrator circuit or one shot that is set up to trigger on a negative-transition of the signal applied to its pin 6 input. The multivibrator"s on time is determined by the values of R1 and Cl. Although R1 is.... -
LED1 and LED2 indicators turn on and remain on, each time the circuit is triggered. During the timing cycle, U1 "s Q output at pin 10 becomes positive when the Q output at pin 11 becomes negative. .. -
Only one LED can be on when the circuit is at rest. Which LED is illuminated is determined by the touch pick-up that last had human contact. Pickup terminal A controls the on condition of LEDl, and terminal B controls the on condition of LED2. .. -
This circuit requires the bridging of two circuits to activate the electronic switch. That circuit does not require a 60-Hz field to operate and can be battery or ac powered. The two-pickup terminals can be made from most any clean metal; they should be.... -
The monostable period is set for about 1 second, as is the usual case. The induced line hum comes through C2, providing a continuous string of trigger pulses. The output becomes low for about 10 ms per second as the monostable times out and then.... -
This touch-actuated switch stays on as long as you keep your finger on the touch plate. Rl sets the input impedance to a high 22 MO. Ql picks up stray signals coupled through your body to the touch plate and amplifies them to tum on Q2, which turns on lamp.... -
By vocalizing the numbers and symbols of its~eypad, the phone provides an audible confirmation that is useful to the blind. The serial-interface, 2 K-byte x 8-bit ROM (!C4) stores programmed sequences of instructions that are executed by the.... -
What makes this control unique is its momentum feature, which adds a degree of realism. The circuit will opera.. -
This highly sensitive movement detector is designed from bipolar transistors and draws a curren.. -
A high-frequency audio signal (15 to 25 kHz) generated by Ul is fed to buffer Ql and SPKR1. A portion is f.. -
Ql is used as an oscillator around 300 kHz. R9 is set so that the oscillator just begins to run. An object ne.. -
Right- and left-channel signals pass through 1 C4-a and -b buffer amps into active crossover IG5; low frequencies are sent to the IC6-c mixer, and middle and high frequencies are sent to the analog delay lines of 1C1 and 1C2. That output passes through.... -
Using an ISD1016 audio record/playback chip (Information Storage Devices, Inc.), this circuit records and plays back messages on command. Although intended for use with transmitters, it can be used as an electronic notepad, etc. .. -
Using digital techniques, this circuit accomplishes the frequency-inversion algorithm via digitization of the audio, inversion of the sign of every alternate sample, and D/A conversion of the resultant data. The result is an inverted frequency spectrum... -
Integrated circuit gates ICl-a and TCl-b form a monostable, whose time constant is determined by C2 and R3. When the transmitter is dekeyed (and then almost immediately rekeyed) point TX+ goes low and takes pin 1 low for a short time. This triggers the.... -
When the touch-on contacts are bridged, pin 6 of Ul-b goes low, which forces its output (the set output) at pin 4 to go high. That high divides along two paths; in one path, the output is applied to pin 2 of Ul-a, which causes its output at pin 3 to go low..... -
This circuit detects an object passing in one direction but ignores it going the opposite way. Two sensors define the sense of direction. The object blocks the light to phototransistor Ql or Q2 first dependent on the direction of approach. When the object.... -
A Touch On/Off Switch is desired, this circuit fills the bill. Two sensitive gate SCRs are interconnected, so that when one of the devices is turned on, the other (if on) is forced off. That toggling effect gives an on/off circuit condition for each of the.... -
When someone touches the touchplate (TP), the resistance of his finger across points A and is added in series to the combination of Rl and R2, the capacitor C2 begins to charge. When the voltage across Cl is finally sufficient to fire NE1, Cl will begin to.... -
? simple heart-beat transducer can be made from an infrared LED and an infrared phototransistor. ?t works because skin acts as a ref1ecti?e surface for infrared light. The lR ref1ecti?ity of one's skin depends ??? the density of blood in it. Blood density.... -
8 ohm output for connecting communication receivers and 8 ohm speaker or low impedance phones, harmful interference suppression continuous random voice transmission. Passband 3.. -
After the power is turned on, 220V AC by the step-down transformer T, VDI ~ VD4 bridge rectifier and Cl filtered output of about 10V DC voltage for the Darlington circuit and s.. -
As shown for the voice-activated lamp circuit. The circuit consists of an operational amplifier FC52, flip-flop, the relay J, a piezoelectric crystal speaker y and other compon.. -
As shown is a practical voice-activated switch, A1 amplifier connected as a conventional microphone B picked up the audio control signal is amplified. After the amplified signa.. -
Circuit as shown, with a touch of a finger when the metal sheet S, N neon tube light, since N and photoresistor RG constitute optocouplers make RG resistance becomes smaller, s.. -
Circuit principle as shown, neon tubes N1, N2 and photosensitive resistance RG1 constitute an optocoupler. When touching the metal sheet S1 with a finger, N1 light, so RG1 resi..
New Circuits
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This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of.... -
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is.... -
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to.... -
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This.... -
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the.... -
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,.... -
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the.... -
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power.... -
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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