Automatic Wiper Control

A continuously working wiper is a big problem when it is raining slightly.The wiper control given here makes the wiper to sweep at rates from 1S to 10 S.

The circuit is build around an astable multivibrator using NE 555.Here the output at pin 3 remains high for a time period set by R2 ,and low for a time period set by R3.The low output pulse drives the transistor pair to drive the wiper motor to make one sweeping cycle and waits for next low pulse to arrive for next sweep.The high going pulse at pin 3 determines how many time should wiper should sweep in a given period of time.

Automatic Wiper Control Circuit Diagram:

Notes:

• Connect the circuit to 12V line from Vehicle and connect the wiper motor and wiper switch as shown in figure.
• For setting the device first find out how much time it is required for the wiper to complete one sweep cycle.Now adjust
• R3 such that wiper makes correct one sweep cycle.Fix R2 some where on the dash board.And now the system is ready to use.
• You can adjust the sweep rate of the wiper using R2 according to the intensity of rain.

Source : Circuits today

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Thermostat using with LM319

This first circuit is designed by me to replace the mechanical switches used in some thermal Electric I have heaters.The electrical contacts to these mechanical thermal switches are always stoned and “no longer be trusted.”They could easily be welded together, the maintenance of these heating on full. It is definitely not good! Coarse adjustment of the temperature is a trimmer on the track, set to give a nominal range When using the fine adjustment.

It is quite difficult in a D-53, manufactured by NEC. The plumb line that is not isolated to the body of the thermistor is arranged. Why is it when you use the wire must be insulated to withstand the high temperatures such as fiberglass insulation against pipe.

Thermostat  Circuit Diagram:

What is the size of the thermistor is the disk diameter 7 mm and a thickness of 2 mm. The end temperature control is a standard isolated potentiometer with a knob and / or good Protection against electric shock. Harter can be adjusted with this controller Auto-On and Off, “which automatically adjusts the room temperature.

The power control for the triac should be a 2 watt potentiometer with a knob isolated and / or Tree for protection against electric shock.  It can also be set up a 2-watt resistor on the circuit, an appropriate level of heat.“In general, full on,” how would the “Normal” setting when you use the contacts.On the chart, show me a 10 Meg resistance hysteresis. This may be of Lower Austria or higherdepending on how many degrees of difference between you and off cycles.Values between 100 K-ohms and 22 ohms, Meg are acceptable.

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Simple Sound-to-Light Converter Schematic

Figure 1 shows a simple ambit for converting an audio arresting (such as one that comes from the apostle terminals of a CD player). The ambit basically consists of a buffer/amplifier date and three clarify circuits: a high-pass filter, a mid-pass filter, and a low-pass filter. The achievement of anniversary clarify ambit drives a light-emitting diode of altered color.

Simple Sound-to-Light Converter Schematic Circuit Diagram:

 

The ascribe arresting is fed to the absorber date through C1. The ethics of RF and RV1 should be called so that the absorber is able to drive the three filters absorbed to its output. The low-frequency, mid-frequency, and high-frequency apparatus of the ascribe arresting are alone accustomed to canyon through the low-pass clarify (bottom filter), the mid-pass clarify (middle filter), and the high-pass clarify (topmost filter), respectively, appropriately amid them from anniversary other.

Changes in the achievement of a clarify account its agnate achievement LED to about-face on and off. In effect, agriculture a connected audio arresting to the ascribe of this ambit causes the LED's to 'dance'.

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Quartz Clock Timebase

Many electronic projects call for a timebase generator, accurate to a second or so. One way of producing this is with a microcontroller, quartz crystal and some software. But a far cheaper and simpler approach is to recycle an old analogue quartz clock. After investigating a number of clocks the author discovered that they all use the same drive method: a tiny solenoid coil is pulsed by a current that reverses direction once a second. In the module illustrated this coil is connected between pins Pulse1 and Pulse2. Most of the time both pins are ‘high’ at supply voltage but every second the clock electronics pull first one and then the other of the pins down to ground for about 25 ms.

Quartz Clock Timebase Circuit Diagram:

We need just five additional components to complete the circuit (see diagram). When either of the pulse pins is at ground potential, the corresponding PNP transistor conducts. Once a second a narrow pulse is produced, which is ideal for our own digital circuitry. The author himself uses one of these clock modules as timebase for a data logger with excel-lent results. Although the clock originally used a 1.5 V supply, this new arrangement works fine with a 3-V lithium batter y. After three months using the same battery there have been no problems whatsoever.

 

Author : Claus Torstrick - Copyright :Elektor

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Voice Activated Switch

This circuit uses an MC2830 to form a voice activated switch ( VOX ). A traditional VOX circuit is unable to distinguish between voice and noise in the incoming signal. In a noisy environment, the switch is often triggered by noise, or the activation sensitivity must be turned down.

Voice Activated Switch Circuit Diagram:

 

This circuit overcomes this weakness. The switch is activated by voice level above the noise and not activated by background noise. This is done by utilizing the differences in voice and noise waveforms. Voice waveforms generally have a wide range of variation in amplitude, whereas noise waveforms are more stable. The sensitivity of the voice activation depends on the value of R6. The voice activation sensitivity is reduced from 3.0dB to 8.0dB above the noise if R6 changes from 14k to 7.0k .

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