Audio level meter (vumeter)

This circuit uses just one IC and a very few number of external components. It displays the audio level in terms of 10 LEDs. The input voltage can vary from 12V to 20V, but suggested voltage is 12V. The LM3915 is a monolithic integrated circuit that senses analog voltage levels and drives ten LEDs  providing a logarithmic 3 dB/step analog display. LED current drive is regulated and programmable, ...

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Obstruction Detector With 12C508 IR

DescriptionThis project is inspired by the DPRG IRPROX project. They have a pretty good PCB layout and idea. I would like to thank them for posting their project for all of us to see and learn from, I wouldn’t have started PIC programming without them, or at least not nearly as quickly come up to speed! The pinout on my board allows either a five-wire or a four-wire connection to be made the former uses a disable line if desired. You can also put in a resistor or use a trimpot to adjust range. The trimpot locations are very generic, most pots will fit. Be careful not to adjust pot to 0 ohms! The IR proximity detector works very well,...

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Proximity Detector Circuit Based 555 IR

Description Sometimes you want a simple solution to a problem and you don’t mind if your main controller has to do the work. This IRPD requires the main robot processor to choose which side to look at, and requires it to “debounce” the results for reliably operation. But, it still works really well without any complex program code. The NAND gate is a standard 74LS00 that you can get anywhere – even Radio Shack, same with the 555, IR detector (RS Everlight or Sharp GP1U58Y) and IR LEDs can also be gotten at Radio Shack. Parts are easy to find and simple to connect. This does not require any fancy wiring or parts placement. Make sure...

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High Voltage Generator/Solid State Tesla Coil

Parts R1 27 Ohm 5W Resistor or 27 Ohm 10W Resistor R2 240 Ohm 5W Resistor or 240 Ohm 10W Resistor BR1 50 Volt, 6 Amp Bridge Rectifier C1 8000uf, 35 Volt Capacitor Q1, Q2 2N3055 NPN Power Transistor T1 24V 5A Transformer (See “Notes”) T2 TV Flyback Transformer (See “Notes”) S1 115V 3A SPST Switch MISC Case, Wire, Heatsinks, Line Cord Notes 1. T2 is a high voltage flyback transformer salvaged from an old TV, or ordered from Fair Radio Sales (see Where To Get Parts). Look for the biggest, most intimidating transformer you can find. Old tube TV’s are a good place to look. The transformer should not have a rectifier built in. 2. You will need...

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Several RC5 Infrared Transmitter Circuit

 1-channel transmitter with 16 selectable codes (PIC12C508) RC5 is not suitable as a barrier to race out to whoever is the winner. Two or more RC5 channel interfere with each other and the protocol itself also takes time for the transfer. If more than one car with RC5 transmitter arrive close together, it can well be the first and the second triggers the stopwatch. IR does not pass through optical barriers through. Two car side by side is thus not before. Infrared is used in daylight outside, not really a good idea (the sun bothers!). With luck we can get a LOT still to reach 3m. Some wondered whether it was possible to hold down...

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40 Watt Fluorescent Strobe Lamp Schematic

Part List: C1/C2 2x Elko standing 1μF/16V C3 1x Ker. Scheibenkondens. 0.1 μF C4 1x HV-capacitor 1μF 350V axial C5 1x Elko stand. 470μF 25 V C6 1x Poly condensation. 0.068 μF 630V D1-4 4x Diode 1N4001 D5 1x Diode 1N4007 L1 1x Ignition coil (such as the normal speed camera strobe) P1 1x Poti 6mm 2.2 M R1/R4 2x Resistor 470R 1 / 4 W R2/R9 2X Resistor 47K 1 / 4 W R3 1x Resistor 10K 1 / 4 W R5 1x Resistor 270R 1 / 4 W R6 1x Resistor 1.2 K 1 / 4 W R7 1x Resistor 22K 1 / 4 W R8 1x Resistor 120K 1 / 4 W Si1 1x Backup medium time 160mA Si2 1x A pair of fuse holders T1/T2 2x ...

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Hammond Transformers 6V6 Push-Pull Tube Amplifier

This 6V6 amp was built following the push-pull (PP) EL84 / 6V6 Dynaco A-410 output transformer schematic. There are a few minor deviations from the original schematics. Instead of Dynaco transformers, Hammond 1608A audio output transformers and a Hammond 272HX power transformer were used. The EL84 / 6V6 PP Dynaco A-410 output transformer schematic showed a 1000 ohm feedback resistor which resulted in bad amplifier oscillation. Feedback resistor Values between about 6 and 10 k-ohm worked well and I settled on 10k. A 5Y3 rectifier would have been to small for a stereo amp so a JJ GZ34 rectifier was used. It became necessary...

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Atmel at89c51 Office-Home Security System

Home security project Securiy is a matter of great concern to all of us in this world. Normally there are four types of security threat to our property. 1 )Thief, an inturder.2)Fire, so we use fire sensor.3)Water spilage /over flow, so we use water sensor.4) Gas leak , we use gas sensor, whenever there is security breach from one of above or any combination of above.The project takes the following action1) Sounds an ALARM to attract your home Security project or public attention .2) If the reset sw is not pressed within 30 seconds the projects takes further action,3) It makes an emergency call to deliver an emergency message stored in speech...

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