Top Circuits Page 185
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This is a very useful RF attenuator circuit which works from 300KHz to the 3GHz range based on the quad PIN diode array HSMP-3816 from Avego. The lower PIN diodes are biased at 1mA which gives about a 40 to 70 ohm impedance. R5 can be increased to increase....
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This circuit allows a smaller control voltage to inversely linearly control a larger output voltage Vo. Another feature is that Vsp the supply to the op-amps can be lower than the output voltage so in theory this circuit could control a output voltage of any....
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The disadvantage of the circuit above is that the supply of the op-amp is tied to the HV supply. Most op-amps are limited to around 30V on the supply, so the circuit wont work for higher output voltages. The circuit below avoids this this problem by....
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Where VD is the voltage drop across the diode, and VTrans is the voltage drop across the transistor. Note that the continuous/discontinuous boundary occurs when io is zero. The main question when designing a converter is what sort of inductor should be used.....
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A relatively simple attachment to my Canon SLR to create a motion activated camera using Arduino. A lot of this was based on and inspired by the intervalometer project at The Honey Jar. I made some changes to his circuit to use a 4N35 optocoupler instead of....
-
This page contains GIF images of the circuit diagram for the Solution interface, the PCB artwork, the board layout, a typical side elevation of the assembly, a parts list, some hints and a little about troubleshooting. This is a self-extracting 2. 5MB file;....
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An analog input is a measurable electrical signal with a defined range that is generated by a sensor and received by a controller. The analog input changes continuously in a definable manner in relation to the measured property. The analog signals generated....
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This project is an instance of the UsbProg project created by Benedikt Sauter. Bene released the schematics, board layout and firmware as an open-source project. I took that project and made these modifications: Or, optionally, place a jumper across JP3 pins....
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A PIC is a Programmable Integrated Circuit. It is the big black ractangle on our breadboard. The standard PIC used in the course was a 28-pin package, the Microchip PIC18F2455. For our project, however, we uses a more robust PIC with more advanced PWM (Pulse....
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The first part of this paper describes the high dynamic range CMOS (HDRC ®) imager a special type of CMOS image sensor with logarithmic response. The powerful property of a high dynamic range (HDR) image acquisition is detailed by mathematical definition and....
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A sensor project which transmits it`s measurements via a 433Mhz wireless communication link. On this page I will describe the details of my self built receiver which receives data from this sensor. To build a general purpose RF receiver module which receives....
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This simple circuit drives 6 LEDs in `Knight Rider scanner mode`. Power consumption depends mainly on the type of LEDs used if you use a 7555 (555 CMOS version)...
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This circuit is intended for charging sealed lead-acid batteries with a solar panel in small and portable applications. The customary diode that prevents the battery from discharging through the solar panel has been replaced by a FET-comparator combination.....
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I finally gave up on the LM7805 circuitry that comes with these devices. The Harbor Freight 42292 charger used to be controlled by a LM317 variable voltage regulator a long time ago. They probably changed the regulator at some point to lower cost or overcome....
-
The guitar is a wonderful musical instrument which is capable of providing both melody and rhythm. However, every guitar player would have experienced the problem of low volume. The guitar is rarely heard unless the surroundings are absolutely quiet! To....
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This project documents how to build and construct your own Brushed Motor ESC for Cars and Boats using a Microchip 12F675 PIC and a small number of standard components. This ESC grew out of an earlier aircraft ESC. A number of people asked for an ESC with....
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The OpenRelief project is building open, modular information solutions for disaster relief , and as part of which they`re developing a range of network-enabled sensors. I offered to help out by prototyping a radiation detector, opting to use an ionisation....
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I was prototyping for the OpenRelief project. Based on a simple ionisation chamber, initial testing used a bank of batteries for the bias power supply and this post details the construction of an inverter to replace these. For details of the detector itself....
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An Internet connection would be a valuable addition to many projects, but often designers are put off by the complexities involved. The NetWorker`, which consists of a small printed circuit board, a free software library and a ready-to-use....
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The requirement was to add a digital readout to an otherwise manually bend roller machine so that we could accurately monitor the amount of material fed into the machine. The readout should be simple to use, require no setup other than initial calibration....
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Diagram shows the basic construction of a forward converter. Whereas the energy is temporarily stored with the flyback converter before it is transferred to the secondary side, in the forward converter, energy is transferred directly between the primary and....
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This is yet another circuit for producing DMX output for entertainment lighting from a PC. Designed with flexibility in mind, a range of circuit configurations are possible. Opting for no isolation requires just a PIC microcontroller and a standard RS-485....
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A fan speed controller for your computer fans. There are two sections: one for manual speed control, and one for automatic (temperature dependent) speed control. There is also a third section for a simple LED output indicator. Why not just run the fans off....
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As the Common Equipment library contains implementation of the equipment used in this sample, the only task for a developer is to properly initialize the device. After installing all the necessary SDKs and updating the device firmware to the newest version,....
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U20 is a 556 timer configured as a one shot multivibrator. The output pulse width is determined by the size of R34 and C24. Pulse width = 1. 1 x R34 x C24 =. 5 seconds. The output on pin 9 is "high" active. The output of U8 is "low" active. Reset initializes....
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Crystal Y1 develops a 14. 31818MHz fundamental frequency clock signal. U31 is a Dual Voltage Controlled Oscillator. The output on pin 10 is a 14. 31818 MHz clock signal called the color clock. R27 can be adjusted to obtain exact output frequency. U30 is a....
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The output F1 pin 17 of the PLA U17 goes "low" when the BASIC ROM is selected. The KERNAL ROM resides at locations $E000 - $FFFF. The output F2 pin 16 of the PLA U17 goes "low" when the KERNAL ROM is selected. The CHARACTER GENERATOR ROM resides at locations....
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U7 is a 6510 microprocessor. One of the features of the 6510 is a built in parallel I/O port (P0-P5). P3 - P5 control most of the cassette interface circuitry. P3 pin p6 of U7 outputs the write data signal to connector CN3 on pins E and 5. P4 is an input....
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U1 is a Complex Interface Adapter (CIA). Both parallel ports are used to decode the keyswitches on the keyboard. Parallel port A signals (PA0 - PA7) are outputs. PArallel port B signals (PB0 - PB7) are inputs. A "0" bin is shifted through the parallel port....
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Each line key has three positions. Centralised it connects the line circuit to line to await a call. Downwards (KK) it operates a K relay which switches the line through to the common equipment. Upwards (KL) the line is connected to the line tester. The....
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I saw a cool app-note from Maxim that described a gamma-photon detector which used a regular PIN-diode as a sensor. The actual circuit looked simple enough so I decided build it, you can never have too many measurement instruments right?....
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It`s very simple circuit using DTMF decoder MT8870 (or CM8870). As shown in the circuit, u`ll receive an interrupt ( if NAND output is connected to INT of the microcontroller) whenever u receive a call or make a call and then u can use yr program to read the....
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Here is my home-made kit of ATmega32 microcontroller interfacing. The ATmega32 controller is rich with features like onboard 32kB in-System programmable flash, 1 KB EEPROM, 2KB SRAM, 10bit ADC (8 channel), SPI bus inteface, TWI (compatible with I2C bus)....
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Here is my project on interfacing of SD Card (microSD). microSD cards are available very cheap nowadays, a great option for having a huge memory in any embedded system project. It is compatible with SPI bus, so the interfacing is easy. SD card adapters are....
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Aim of this project is to present a way to store a large quantity of data into microSD card in files with FAT32 format. Here, ATmega32 is used for data collection and microSD interface. The data is received from in-build 8-channel ADC of ATmega32. One....
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An alternative to the infamous ROG `s Ruby amp. As you see it shares with the Ruby the same topology: a buffer and a chip amp. It uses a JFET buffer with a MPF102 and the 1W TDA7052 chip. It is a clean amp and it reacts very well with any pedal in front of....
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Another cause of voltage drift is the input current of IC1, which slowly charges capacitor C1, this can especially be seen when the output voltage is about 0 Volt...
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Every next stage is adding 1700 Volts, so with 12 stages we get more then 20 kV, this voltage can however only be reached when the output of the cascade is not loaded...
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As transformer a toroidal transformer (2x12V 15VA) is used, because this gives much less energy losses then an E-I core transformer as used in the original mains adaptor (for more info, click here )...
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The following is one of the most rare and special documents here at the DigiBarn, the only known copy of the complete schematic specification of the 512K Macintosh Logic Board. Daniel Kottke co-authored this design which served as the basis for the 64K....
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This Programming interface circuit sends the programming signals from the USB cable to the FPGA chip directly, through a standardized 10-PIN interface. Technically there are only 4 or 5 signal pins used, excluding GND and unused interface pins from the....
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I am planning on doing an s-video and rca jack mod on my Genesis. The mods I see done seem to all use the headphone jack as the source of the stereo sound. Is this the only way? I would prefer to have the output not be controlled by the volume slider. Is it....
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One day I bought an old pong console from an old lady at a flea market. When I got back at home I hooked it up to the TV But the problem was that I didn`t have the AC adapter for it So I took C batteries to insert them in the console but when I removed the....
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We will bypass the mechanical snooze switch on top, and instead turn the alarm clock off in a much more fun way: punching it! Hopefully along the way I will be able to teach you some techniques that are useful in reverse engineering, so you can apply them to....
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Dimmer Switch - Dimmer Switch Working, Installation, Circuits and Explanation....
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The concept behind the light dimmer is to control the voltage to the light lamp or any source. Light dimmers regulate the voltage to the source they are connected to. This regulation of voltage increases or decreases the light intensity. Light dimmers first....
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In electronics, a digital-to-analog converter (DAC or D-to-A) is a device for converting a digital (usually binary) code to an analog signal (current, voltage or electric charge). You can use DAC for testing circuits and amplifiers or for generating the high....
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An L7805 provides a 5v rail. The input and output of the reg is bridged by a 470 F and a 10 F capacitor respectively to try and smooth things out a bit. The 5v rail created by the L7805 then powers the MAX232 level shifter and the GPS module itself. Thee....
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This circuit uses a synthesized sound chip from Holtek, the HT-2811. This reproduces the sound of a ""ding-dong"" chiming doorbell. Additionally, the circuit includes a CMOS 4026 counter display driver IC to count your visitors....
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-
A diagram of an active loudspeaker. The LF353 of, National Semiconductor, is going to split audio signal into three bands. SANYO LA47536 is going to amplify these signals. In stereo mode, we shall have the action of eight high speakers who are going to....
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A hifi preamplifier designed to convert high output impedance amplifiers to 600 ohm outputs....
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A high quality microphone preamplifier using a single power supply, suitable for dynamic or electret microphones....
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An electronic version of a chirping canary. May be used as an alarm, a sound effects generator or perhaps a replacement doorbell....
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-
This Mark3 version of the Infra Red extender is a special version designed to control appliances that use high frequency modulated IR remote controls....
-
A circuit to extract and measure the modulated carrier of an Infra Red remote control. Note that the circuit does not physically separate control pulses from modulation, but amplifies the completereceived signal allowing the waveform to be displayed ideally....
-
A low frequency test oscillator for testing tone controls and experimenting....
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An electromagnetic field probe designed to detect changing electric and magnetic fields....
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This circuit can measure both small signal hfe and DC current gain hFE of a low to medium power power transistor....
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Using a single 7812 IC voltage regulator and multiple outboard pass transistors, this power supply can deliver output load currents of up to 30 amps....
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This is a simple but reliable device based one of the oldest integrated voltage regulators of them all - the LM723....
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A 12 Volt high current 20 Amp power supply. The output voltage is variable from 12.2 Volt to 14.4V so can be set for any device requiring voltage and current in that range. This PSU uses an LM723 as the regulator, 4 parallel connected outboard pass....
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A Short Wave Receiver based on the MK484 (formerly ZN414) that includes the tropical bands and 49 metre bands....
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-
This is the circuit that sparked off all the other Link Telephone Intercom designs. Originally designed back in 1996 with heavy duty relays and their contact banks, it was updated late last year with the addition of IC1 in place of a simpler transistor....
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-
The circuit you are about to see is the culmination of some effort at improving the basic Link intercom design. You may think that pulse dialing is `old hat` nowadays, but the exercise of building and testing the Link `P` in this format, and understanding....
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This is a great intercom circuit that can be used in many ways. It uses 22V to operate and maybe it will work at a lower voltage (you can try it). For input/output it uses a loundspeaker (20-45 Ohm) on each side...
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This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp forms a current-to-voltage converter and the second op-amp buffers the output to drive the piezo transducer. R5 sets the switching....
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This circuit is intended for children fun, and is suitable to be installed on bicycles, battery powered cars and motorcycles, but also in models and other games. With SW1 positioned as shown in the circuit diagram it reproduces the typical dual tone sound of....
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This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants` pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is....
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This circuit generates a two-tone effect very much alike the cuckoo sound. It can be used for door-bells or other purposes thanks to a built-in audio amplifier and loudspeaker Used as a sound effect generator it can be connected to external amplifiers, tape....
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This simple counter can be used to count pulses, as the basis for a customer counter (like you see at the doors of some stores), or for anything else that may be counted. The circuit accepts any TTL compatible logic signal, and can be expanded easily (see....
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This is an efficient flyback driver for modern cylindrical rectified television flybacks. Many sites doesn`t provide circuits driving these transformers, they simply say that they are bad. I don`t agree. In fact I built this circuit. I spent a lot of time....
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When the phototransistor is stroken by IR light it conducts and the voltage between the 1Mohm resistor(arbitrary) and the phototrans drops from VCC to lower values. When the voltage drops lower than VCC/3 the 555 is triggered and goes high (from 0 TO VCC).....
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L2 RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit. ) With their C7, C8 we adapt the resistance of aerial....
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This SMD FM transmitter has an operating frequency of about 80 to 115MHz. Under reasonable circumstances you will be able to receive its signal at a distance of about 200 meters. Although it is low-power, it might be illegal in your part of the planet.....
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Apart from the diode (which replacement would need a PbS, Lead Sulphyde, galena cristal) everything you can see in the circuit (for the no power version) can be built with enamel wire, alluminium cooking foil, carton wax and so on. The real painful part is....
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The 60 Watt linear amplifier is simple all solid state circuit using power mosfet IRF840. The IRF series of power transistors are available in various voltage and power ratings. A single IRF840 can handle maximum power output of 125 watts. Since these....
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FM and AM transmitter in one small device built of cd4001 integrated circuit. It broadcasts on 20MHz(AM) and 100Mhz(FM)....
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This is a spectacular but completely useless project. It lights Ultra-Bright LEDs in a sequence and each LED flashes brightly very briefly. The LEDs light-up going around and around since they are mounted in a circle (on a CD), then they pause before chasing....
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Flying hand launch gliders means living with small capacity receiver NiCad battery packs. These small packs are light, but have the distinct disadvantage of rapidly depleting. You can carefully time your flights, but you end up either crashing when your....
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This launch controller can be used with low voltage battery igniters, which fire rocket engines in model rockets such as the Estes range. These circuits are electrical, only switches and contacts are involved. First the circuit for a single rocket: The only....
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Any "button" of any remote control may be used to work this universal switch. The button must be pressed for two seconds (determined by R3 and C2) before the relay will operate. Once operated the circuit will remain in this state (latched) until reset. To....
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This circuit will allow you to turn on any piece of equipment that operates on 115 volts ac. The reciever circuit is based on the Radio Shack infrared receiver module(MOD), part number 276-137. It is also available from some of the other sources listed on my....
This is a very useful RF attenuator circuit which works from 300KHz to the 3GHz range based on the quad PIN diode array HSMP-3816 from Avego. The lower PIN diodes are biased at 1mA which gives about a 40 to 70 ohm impedance. R5 can be increased to increase....
This circuit allows a smaller control voltage to inversely linearly control a larger output voltage Vo. Another feature is that Vsp the supply to the op-amps can be lower than the output voltage so in theory this circuit could control a output voltage of any....
The disadvantage of the circuit above is that the supply of the op-amp is tied to the HV supply. Most op-amps are limited to around 30V on the supply, so the circuit wont work for higher output voltages. The circuit below avoids this this problem by....
Where VD is the voltage drop across the diode, and VTrans is the voltage drop across the transistor. Note that the continuous/discontinuous boundary occurs when io is zero. The main question when designing a converter is what sort of inductor should be used.....
A relatively simple attachment to my Canon SLR to create a motion activated camera using Arduino. A lot of this was based on and inspired by the intervalometer project at The Honey Jar. I made some changes to his circuit to use a 4N35 optocoupler instead of....
This page contains GIF images of the circuit diagram for the Solution interface, the PCB artwork, the board layout, a typical side elevation of the assembly, a parts list, some hints and a little about troubleshooting. This is a self-extracting 2. 5MB file;....
An analog input is a measurable electrical signal with a defined range that is generated by a sensor and received by a controller. The analog input changes continuously in a definable manner in relation to the measured property. The analog signals generated....
This project is an instance of the UsbProg project created by Benedikt Sauter. Bene released the schematics, board layout and firmware as an open-source project. I took that project and made these modifications: Or, optionally, place a jumper across JP3 pins....
A PIC is a Programmable Integrated Circuit. It is the big black ractangle on our breadboard. The standard PIC used in the course was a 28-pin package, the Microchip PIC18F2455. For our project, however, we uses a more robust PIC with more advanced PWM (Pulse....
The first part of this paper describes the high dynamic range CMOS (HDRC ®) imager a special type of CMOS image sensor with logarithmic response. The powerful property of a high dynamic range (HDR) image acquisition is detailed by mathematical definition and....
A sensor project which transmits it`s measurements via a 433Mhz wireless communication link. On this page I will describe the details of my self built receiver which receives data from this sensor. To build a general purpose RF receiver module which receives....
This simple circuit drives 6 LEDs in `Knight Rider scanner mode`. Power consumption depends mainly on the type of LEDs used if you use a 7555 (555 CMOS version)...
This circuit is intended for charging sealed lead-acid batteries with a solar panel in small and portable applications. The customary diode that prevents the battery from discharging through the solar panel has been replaced by a FET-comparator combination.....
I finally gave up on the LM7805 circuitry that comes with these devices. The Harbor Freight 42292 charger used to be controlled by a LM317 variable voltage regulator a long time ago. They probably changed the regulator at some point to lower cost or overcome....
The guitar is a wonderful musical instrument which is capable of providing both melody and rhythm. However, every guitar player would have experienced the problem of low volume. The guitar is rarely heard unless the surroundings are absolutely quiet! To....
This project documents how to build and construct your own Brushed Motor ESC for Cars and Boats using a Microchip 12F675 PIC and a small number of standard components. This ESC grew out of an earlier aircraft ESC. A number of people asked for an ESC with....
The OpenRelief project is building open, modular information solutions for disaster relief , and as part of which they`re developing a range of network-enabled sensors. I offered to help out by prototyping a radiation detector, opting to use an ionisation....
I was prototyping for the OpenRelief project. Based on a simple ionisation chamber, initial testing used a bank of batteries for the bias power supply and this post details the construction of an inverter to replace these. For details of the detector itself....
An Internet connection would be a valuable addition to many projects, but often designers are put off by the complexities involved. The NetWorker`, which consists of a small printed circuit board, a free software library and a ready-to-use....
The requirement was to add a digital readout to an otherwise manually bend roller machine so that we could accurately monitor the amount of material fed into the machine. The readout should be simple to use, require no setup other than initial calibration....
Diagram shows the basic construction of a forward converter. Whereas the energy is temporarily stored with the flyback converter before it is transferred to the secondary side, in the forward converter, energy is transferred directly between the primary and....
This is yet another circuit for producing DMX output for entertainment lighting from a PC. Designed with flexibility in mind, a range of circuit configurations are possible. Opting for no isolation requires just a PIC microcontroller and a standard RS-485....
A fan speed controller for your computer fans. There are two sections: one for manual speed control, and one for automatic (temperature dependent) speed control. There is also a third section for a simple LED output indicator. Why not just run the fans off....
As the Common Equipment library contains implementation of the equipment used in this sample, the only task for a developer is to properly initialize the device. After installing all the necessary SDKs and updating the device firmware to the newest version,....
U20 is a 556 timer configured as a one shot multivibrator. The output pulse width is determined by the size of R34 and C24. Pulse width = 1. 1 x R34 x C24 =. 5 seconds. The output on pin 9 is "high" active. The output of U8 is "low" active. Reset initializes....
Crystal Y1 develops a 14. 31818MHz fundamental frequency clock signal. U31 is a Dual Voltage Controlled Oscillator. The output on pin 10 is a 14. 31818 MHz clock signal called the color clock. R27 can be adjusted to obtain exact output frequency. U30 is a....
The output F1 pin 17 of the PLA U17 goes "low" when the BASIC ROM is selected. The KERNAL ROM resides at locations $E000 - $FFFF. The output F2 pin 16 of the PLA U17 goes "low" when the KERNAL ROM is selected. The CHARACTER GENERATOR ROM resides at locations....
U7 is a 6510 microprocessor. One of the features of the 6510 is a built in parallel I/O port (P0-P5). P3 - P5 control most of the cassette interface circuitry. P3 pin p6 of U7 outputs the write data signal to connector CN3 on pins E and 5. P4 is an input....
U1 is a Complex Interface Adapter (CIA). Both parallel ports are used to decode the keyswitches on the keyboard. Parallel port A signals (PA0 - PA7) are outputs. PArallel port B signals (PB0 - PB7) are inputs. A "0" bin is shifted through the parallel port....
Each line key has three positions. Centralised it connects the line circuit to line to await a call. Downwards (KK) it operates a K relay which switches the line through to the common equipment. Upwards (KL) the line is connected to the line tester. The....
I saw a cool app-note from Maxim that described a gamma-photon detector which used a regular PIN-diode as a sensor. The actual circuit looked simple enough so I decided build it, you can never have too many measurement instruments right?....
It`s very simple circuit using DTMF decoder MT8870 (or CM8870). As shown in the circuit, u`ll receive an interrupt ( if NAND output is connected to INT of the microcontroller) whenever u receive a call or make a call and then u can use yr program to read the....
Here is my home-made kit of ATmega32 microcontroller interfacing. The ATmega32 controller is rich with features like onboard 32kB in-System programmable flash, 1 KB EEPROM, 2KB SRAM, 10bit ADC (8 channel), SPI bus inteface, TWI (compatible with I2C bus)....
Here is my project on interfacing of SD Card (microSD). microSD cards are available very cheap nowadays, a great option for having a huge memory in any embedded system project. It is compatible with SPI bus, so the interfacing is easy. SD card adapters are....
Aim of this project is to present a way to store a large quantity of data into microSD card in files with FAT32 format. Here, ATmega32 is used for data collection and microSD interface. The data is received from in-build 8-channel ADC of ATmega32. One....
An alternative to the infamous ROG `s Ruby amp. As you see it shares with the Ruby the same topology: a buffer and a chip amp. It uses a JFET buffer with a MPF102 and the 1W TDA7052 chip. It is a clean amp and it reacts very well with any pedal in front of....
Another cause of voltage drift is the input current of IC1, which slowly charges capacitor C1, this can especially be seen when the output voltage is about 0 Volt...
Every next stage is adding 1700 Volts, so with 12 stages we get more then 20 kV, this voltage can however only be reached when the output of the cascade is not loaded...
As transformer a toroidal transformer (2x12V 15VA) is used, because this gives much less energy losses then an E-I core transformer as used in the original mains adaptor (for more info, click here )...
The following is one of the most rare and special documents here at the DigiBarn, the only known copy of the complete schematic specification of the 512K Macintosh Logic Board. Daniel Kottke co-authored this design which served as the basis for the 64K....
This Programming interface circuit sends the programming signals from the USB cable to the FPGA chip directly, through a standardized 10-PIN interface. Technically there are only 4 or 5 signal pins used, excluding GND and unused interface pins from the....
I am planning on doing an s-video and rca jack mod on my Genesis. The mods I see done seem to all use the headphone jack as the source of the stereo sound. Is this the only way? I would prefer to have the output not be controlled by the volume slider. Is it....
One day I bought an old pong console from an old lady at a flea market. When I got back at home I hooked it up to the TV But the problem was that I didn`t have the AC adapter for it So I took C batteries to insert them in the console but when I removed the....
We will bypass the mechanical snooze switch on top, and instead turn the alarm clock off in a much more fun way: punching it! Hopefully along the way I will be able to teach you some techniques that are useful in reverse engineering, so you can apply them to....
The concept behind the light dimmer is to control the voltage to the light lamp or any source. Light dimmers regulate the voltage to the source they are connected to. This regulation of voltage increases or decreases the light intensity. Light dimmers first....
In electronics, a digital-to-analog converter (DAC or D-to-A) is a device for converting a digital (usually binary) code to an analog signal (current, voltage or electric charge). You can use DAC for testing circuits and amplifiers or for generating the high....
An L7805 provides a 5v rail. The input and output of the reg is bridged by a 470 F and a 10 F capacitor respectively to try and smooth things out a bit. The 5v rail created by the L7805 then powers the MAX232 level shifter and the GPS module itself. Thee....
This circuit uses a synthesized sound chip from Holtek, the HT-2811. This reproduces the sound of a ""ding-dong"" chiming doorbell. Additionally, the circuit includes a CMOS 4026 counter display driver IC to count your visitors....
A diagram of an active loudspeaker. The LF353 of, National Semiconductor, is going to split audio signal into three bands. SANYO LA47536 is going to amplify these signals. In stereo mode, we shall have the action of eight high speakers who are going to....
A hifi preamplifier designed to convert high output impedance amplifiers to 600 ohm outputs....
A high quality microphone preamplifier using a single power supply, suitable for dynamic or electret microphones....
An electronic version of a chirping canary. May be used as an alarm, a sound effects generator or perhaps a replacement doorbell....
This Mark3 version of the Infra Red extender is a special version designed to control appliances that use high frequency modulated IR remote controls....
A circuit to extract and measure the modulated carrier of an Infra Red remote control. Note that the circuit does not physically separate control pulses from modulation, but amplifies the completereceived signal allowing the waveform to be displayed ideally....
A low frequency test oscillator for testing tone controls and experimenting....
An electromagnetic field probe designed to detect changing electric and magnetic fields....
This circuit can measure both small signal hfe and DC current gain hFE of a low to medium power power transistor....
Using a single 7812 IC voltage regulator and multiple outboard pass transistors, this power supply can deliver output load currents of up to 30 amps....
This is a simple but reliable device based one of the oldest integrated voltage regulators of them all - the LM723....
A 12 Volt high current 20 Amp power supply. The output voltage is variable from 12.2 Volt to 14.4V so can be set for any device requiring voltage and current in that range. This PSU uses an LM723 as the regulator, 4 parallel connected outboard pass....
A Short Wave Receiver based on the MK484 (formerly ZN414) that includes the tropical bands and 49 metre bands....
This is the circuit that sparked off all the other Link Telephone Intercom designs. Originally designed back in 1996 with heavy duty relays and their contact banks, it was updated late last year with the addition of IC1 in place of a simpler transistor....
The circuit you are about to see is the culmination of some effort at improving the basic Link intercom design. You may think that pulse dialing is `old hat` nowadays, but the exercise of building and testing the Link `P` in this format, and understanding....
This is a great intercom circuit that can be used in many ways. It uses 22V to operate and maybe it will work at a lower voltage (you can try it). For input/output it uses a loundspeaker (20-45 Ohm) on each side...
This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp forms a current-to-voltage converter and the second op-amp buffers the output to drive the piezo transducer. R5 sets the switching....
This circuit is intended for children fun, and is suitable to be installed on bicycles, battery powered cars and motorcycles, but also in models and other games. With SW1 positioned as shown in the circuit diagram it reproduces the typical dual tone sound of....
This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants` pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is....
This circuit generates a two-tone effect very much alike the cuckoo sound. It can be used for door-bells or other purposes thanks to a built-in audio amplifier and loudspeaker Used as a sound effect generator it can be connected to external amplifiers, tape....
This simple counter can be used to count pulses, as the basis for a customer counter (like you see at the doors of some stores), or for anything else that may be counted. The circuit accepts any TTL compatible logic signal, and can be expanded easily (see....
This is an efficient flyback driver for modern cylindrical rectified television flybacks. Many sites doesn`t provide circuits driving these transformers, they simply say that they are bad. I don`t agree. In fact I built this circuit. I spent a lot of time....
When the phototransistor is stroken by IR light it conducts and the voltage between the 1Mohm resistor(arbitrary) and the phototrans drops from VCC to lower values. When the voltage drops lower than VCC/3 the 555 is triggered and goes high (from 0 TO VCC).....
L2 RFC (resistance 1MOhm with wrapped around her inductor of enough coils from fine isolated wire. Scratch of utmost inductor and you stick in utmost the resistance making thus a parallel L-r circuit. ) With their C7, C8 we adapt the resistance of aerial....
This SMD FM transmitter has an operating frequency of about 80 to 115MHz. Under reasonable circumstances you will be able to receive its signal at a distance of about 200 meters. Although it is low-power, it might be illegal in your part of the planet.....
Apart from the diode (which replacement would need a PbS, Lead Sulphyde, galena cristal) everything you can see in the circuit (for the no power version) can be built with enamel wire, alluminium cooking foil, carton wax and so on. The real painful part is....
The 60 Watt linear amplifier is simple all solid state circuit using power mosfet IRF840. The IRF series of power transistors are available in various voltage and power ratings. A single IRF840 can handle maximum power output of 125 watts. Since these....
This is a spectacular but completely useless project. It lights Ultra-Bright LEDs in a sequence and each LED flashes brightly very briefly. The LEDs light-up going around and around since they are mounted in a circle (on a CD), then they pause before chasing....
Flying hand launch gliders means living with small capacity receiver NiCad battery packs. These small packs are light, but have the distinct disadvantage of rapidly depleting. You can carefully time your flights, but you end up either crashing when your....
This launch controller can be used with low voltage battery igniters, which fire rocket engines in model rockets such as the Estes range. These circuits are electrical, only switches and contacts are involved. First the circuit for a single rocket: The only....
Any "button" of any remote control may be used to work this universal switch. The button must be pressed for two seconds (determined by R3 and C2) before the relay will operate. Once operated the circuit will remain in this state (latched) until reset. To....
This circuit will allow you to turn on any piece of equipment that operates on 115 volts ac. The reciever circuit is based on the Radio Shack infrared receiver module(MOD), part number 276-137. It is also available from some of the other sources listed on my....
