Ultrasonic Range Meter

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Ultrasonic

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Light to Frequency Converter TSL220

A large area photodiode and current to frequency converter combined in a clear plastic 8-pin DIL package. The output is a pulse train whose frequency is directly proportional to the light intensity. The output is CMOS compatible (use a 3k3 pulldown resistor to drive LS TTL) and the frequency can be measured by pulse counting, period timing or integration techniques. The photodiode has a wide dynamic range, high sensitivity and high noise immunity. The output frequency range is determined by a capacitor in the range 10pf to 100pf, which permits the output frequency to fall within some suitable range for any given light intensity.

Intermittent wiper controller by 2N4401

The intermittent wiper circuit shown above causes the auto’s windshield wipers to wipe once every several seconds instead of constantly wiping. The circuit may be added to older cars to provide the intermittent function or it may be used to replace broken wiper circuits in modern cars. The delay is continuously adjustable with the potentiometer but switch selected fixed resistors may also be used, if desired. The circuit should be connected to +12 volts at the same point as the original wiper power switch so that the proper fuse protection is preserved. The 12 volt relay should have contacts rated for a few amps since the wiper motor will draw a considerable start current but most automotive relays are adequate. The circuit should be quite trouble-free and will work on the first try if no wiring errors are made!

PWM DC motor control with SG3525

This control circuit is ideal for the accurate control of DC motors as well as other applications like lighting levels and small heaters etc. The circuit converts a DC voltage into series of pulses, such that the pulse duration is directly proportion to the value of the DC voltage. The great advantage of such a circuit is that almost no power is lost in the control circuit. This circuit protects against overload and short circuit, PWM range can be adjusted from 0-100%, PWM frequency is 100HZ-5KHZ adjustable. Operation voltage from +8V~ 35V, minimum current consumption is about 35mA. Maximum current can go up to 6.5A. Efficiency better than 90% at full load. The functions of three trim pots are as follow: VR1: setting the minimum output voltage VR3: setting the maximum output voltage VR2: setting the output frequency.

This is circuit PWM Control Speed Motor 12V with IC TL494

I See from Idea Circuit by joe (aircraftdesigner) Good Elecronics user. Thank you very much.

detail
- For Control speed motor 12V max 15A.
- R6 Control speed motor.
- Driver Motor by Mosfet IRFZ48.
- Control at Frequency 100HZ
- Adjust PWM duty cycle From 0 to 100%
- rise and fall time = 10uS

PWM Speed Motor Controller By IC 555

This 555 timer based PWM controller features almost 0..100% pulse width regulation using R1, while keeping the oscillator frequency relatively stable. The frequency is dependent on values of R1 and C1, values shown will give a frequency range from about 170 to 200 Hz. Any 555 chip will do, CMOS is fine as well. Diodes are not critical, I used 1N4148. Total cost of parts is about $2. As the whole thing is quite trivial, it's very easy to build on prototyping board like I did (as you can see, one of capacitors - C1 is replaced with different value, 0.047 uF to be precise):

Stepper Motor Driver using L298 and L297

This Step motor controller uses the L297 and L298N driver combination; it can be used as stand alone or controlled by microcontroller. It is designed to accept step pulses at up to 25,000 per second. An on-board step pulse generator can be used if desired (40-650 pps range). Single supply operation is standard All eight inputs are pulled up to +5V by RP1 (4.7K) and are buffered by 74HC244. The output driver is capable of driving up to 2Amp into each phase of a two-phase bipolar step motor. The motor winding current is limited by means of a 35KHZ-chopper scheme. The potentiometer (R6) is for varying the winding currents. The nature of the chopping scheme eliminates the need for external current limiting resistors on the motor windings; this simplifies connections and increases efficiency. A useful of this design is the "idle" current reduction mode. The amount of reduction is fixed at approximately 50% from whatever the running current is set at. Similarly, the motor current can be commanded to shut entirely off. The internal +5V voltages required for operation are derived from the stepper motor supply. The motor supply voltages should be at least 9V, but must never exceed 32V.

DC24V to AC220V Inverter 300W by NE555,CA3130,MJ15003

This is circuit Inverter 300, Input battery 24V to Output 220V 50Hz 300W.
Use Component IC 4027,NE555,CA3130,7805 and Transister MJ15003.

110VAC Inverter for Automobile by 4013, 555, 4020, and 4049

The design depends on the windings ratio and the value of the car battery to produce an AC waveform of approximately 95 volts RMS. No filtering is performed on the secondary since the transformer blocks most of the sharp edges from the input waveform.

All of the devices (4013, 555, 4020, and 4049) should have their supply pins connected to the +12 supply. The nice thing about CMOS logic is that it will operate over a wide range of voltages. Before connecting the center tap of the transformer, adjust R3 until the signal on U5 pin 13 is 120Hz.

The 4013’s are used to produce a 60Hz square wave with an accurate 50% duty cycle and to force the FET switches operate in a break-before-mate manner. The 4049’s have enough drive capability to snap the FET’s off and on very quickly.

Powerful Siren by BC337

R1,R3____________1K 1/4W Resistors
R2,R5___________10K 1/4W Resistors
R4_____________220R 1/4W Resistor
R6_____________220K 1/4W Resistor
R7______________22K 1/4W Resistor
R8_____________100K 1/4W Resistor

C1,C2___________22µF 25V Electrolytic Capacitors
C3______________10nF 63V Polyester or Ceramic Capacitor
C4______________47µF 25V Electrolytic Capacitor

Q1,Q2_________BC557 45V 100mA PNP Transistors
Q3____________BC337 45V 800mA NPN Transistor

SW1___________SPST Toggle or Slide Main Switch (See Notes)
P1____________SPST Pushbutton Operating Switch

SPKR__________8 Ohm Loudspeaker

B1____________12V Battery

Ultrasonic Parking Sonar by 4017

It works on the sonar principle, sending an ultrasound burst and listening for first echo. The burst generated by the oscillator built around U4D (you must set the frequency using TR2 to have 40 kHz or the maximum sensitivity), U4E buffers the output and U4F boost the signal doubling the voltage span across the TX piezo transducer .

A new burst is generated each time the decade counter (4017 in the circuit diagram) is in its reset state, that is output 0 is selected. The other outputs (1 to 9) are scanned sequentially following burst generation, until an echo strikes back the RX receiver. It is then amplified by the transistor input stage, triggering the monostable built around U4A - U4B. The monostable stops temporarly the scanning, and a led corresponding to the obstacle distance appears as continuously lit. The buzzer bleeps when the first led (minimum distance) il lit.

To set up:

Set TR2 for maximum sensitivity (usually 40 kHz for most commercially available ultrasonic transducer pairs).
Set TR1 for your preferred range. Setting it to minimum resistance shortens the distance for each led (minimum range). I suggest a range of 90 cm (10 cm each led).

Hints:

First of all, be careful not to exchange the ultrasonic transmitter with the receiver: they look very similar, and I suggest you to mark them very clearly from the moment you buy them.
During setup, place the ultrasonic transducers over a soft surface, near the border of a table, 10 cm apart of each other pointing outwards the table. Then adjust TR1 and TR2 using a rigid surface (for example a metal sheet) placed in front of sensors, at a variable distance.

Link : http://www.uashem.com/pageid-419.html

Lightning Storm Detector

Detects approaching lightning storms by monitoring the RF spectrum

Reverse engineered schematic diagram of a mass produced lightning detector. The RF signal from lightning is quite strong and broad in spectrum so a tuned circuit is not required at the antenna input stage. Too much sensitivity will cause false alarms in a simple receiver such as this one. The circuit uses clever pulse timing and intergration techniques to discriminate between real lightning and other RF interference. The short antenna provides bandwidth limitation towards the low end of the spectrum, while the metal gate CMOS logic running on a mere 6 volts caps the high frequency response. Latch-up is not a problem for the metal gate CMOS logic during normal operation because the operating voltage is only 6VDC, but if you happen to turn the unit off and then back on extremely quickly while the alarm is sounding, then CMOS gate B might get destroyed by the discharge of the 47uF capacitor at pins 1&2. Put a large capacitor between pins 1&14 of one of the the CMOS gates to prevent this.

Read Source:
http://www.members.shaw.ca/novotill/SfericDetector/index.htm

Digital voice Recordr for 60 seconds & play

This project is based on ISD2560P IC which allows us to record 60 seconds voice and playback it with very high quality. As shown in the schematic, we input the voice by using an electret microphone. If a dynamic microphone is used, R2,R3,R4 resistors and C3,C5,C7 capacitors will be omitted and microphone will be connected to 17 and 18 numbered pins directly. Since it has better frequency response, we choose electret microphone in this project.

Digital Voice Record and Playback Circuit Schematic Controlling the circuit is very simple. Sw1 switches between record and playback modes. Push button B1 is used for start and pause functions. B2 stops the process.

To record voice, first move Sw1 to record position and push B1 once. IC will start recording and during this process red LED will bright. One push to B1 pauses and second push continues recording. You can record 60 seconds by this way. To stop recording push B2.

To listen the voice recorded before, move Sw1 to playback position then push B1. During the playback process red LED will bright again. One push to B1 pauses and second push continues playing. To stop playback push B2.