Vacuum Tubes Valves
Musical & effects
Yagi Uda Antennas
Metal Detector Circuits
Liquid Sensing Circuits
Light Sensing Circuits
Voltage Detector Circuits
Air-Gas Detection Circuits
Human Sensing Circuits
RF & Radiation
Optical Sensing Circuits
Free Energy Circuits
AC to DC & DC to DC
Solar Cell Circuits
Micro Power Circuits
Switching Power Supplies
Light Laser LED
Digital to Analog
Analog to Digital
Data Bus Circuits
Voltage to Pulse
Current to Voltage
Frequency to Voltage
RF Converter Circuits
Sine to Square Wave
Voltage to Current
voltage to frequency
Period to Voltage
Video Wall circuits
TV Video Circuits
Motor Control Circuits
8051 / 8052
PCB CAD Software
Car bike Circuits
555 Timer Circuits
Remote Control Toy
H Bridge Circuit
DIY HV Variable Cap
DIY PMA alternator
Interconnection & Timing
Digital Signal Integrity
Digital & Bipolars
Sensors & Detectors
Regulated Power Supply
4 Band Resistor
5 Band resistor
6 Band resistor
USB Interface Circuits
USB Interface Circuits
Wireless Keylogger circuit
The Wireless Keylogger consists of two main building blocks: the transmitter, and the receiver. The actual keylogging takes place in the transmitter, which is in fact a PS/2 hardware keylogger, with a built-in 2.4 GHz wireless module. Captured keystroke data is transmitted through the radio-link in real-time, rather than getting stored. The...
AVR-P40-USB-8535 BOARD FOR AT90S8535
There are two ways to program AVR-P40-USB: with ICSP port and with JTAG port. To program via ICSP port you need serial port or parallel port AVR-ICSP programmer dongle (Olimex part # AVR-PG1B or AVR-PG2B). The serial port ICSP programmer (AVR-PG1B) works with PonyProg software by from Claudio Lanconelli and the latest release may be...
Add current boost to a USB charger
The popular USB interface can charge a portable device while transferring data. But for high-capacity batteries, the 500-mA output current of USB hosts and powered hubs greatly extends the charging time. (Unpowered USB hubs supply no more than 100 mA.) Thus, a system that accepts charging power from an ac adapter as well as the USB port is more...
USB Microphone Line Level Preamp
The computer needs at least 180 millivolts peak-to-peak and the condenser microphone in my headset produces about 20 millivolts peak-to-peak into a 2.2k load with normal speech levels. There are USB ports on the machines, so I can use that for +5 volts. After a quick look in my parts boxes, I decided to put the input jack and output plug on the...
Simplest and low cost USB AVR
This is the low cost AVR programmer using attiny2313. The schematic diagram is given below. First setup the circuit as shown. One important care taken to make fuse bit avrdude -c usbasp -p t2313 -U hfuse:w:0xdf:m -U lfuse:w:0xef:m If you use serial port to write the program , use stk200 command instead of usbasp.
The SCHAER+ programmer is a programmer for PIC18 family from a PC parallel port (LPT). It is derivated from the SCHAER programmer I used to download my projects in PIC1684. The SCHAER+ programmer should be improved to use a USB connection, without any external power supply...
Build a UPS for USB devices
Portable systems often include circuitry that derives power from an external source, such as USB. When the system disconnects from the USB supply, a battery takes over and supplies current via a dc/dc converter. A diode-OR connection (Figure 1 offers the easiest way to ensure that the supply voltage doesn`t sag during this switchover to the...
ICs Simplify Battery Charging from the USB
The charger is based on the LTC4053a standalone timer-terminated constant current/constant voltage linear charger. The LTC4053 features a thermal loop which maximizes the charging rate under all conditions by regulating the maximum die temperature. Less sophisticated linear chargers must run lower charging rates or risk overheating, thus...
Dual Current-Limiting Switch for USB
The circuit in Figure 1 uses the MIC2545A-2 and the MIC2778. The MIC2545A-2 is a programmable current limit high-side switch that is capable of having current-limit up to 2.5A.
USB 1.1 Controller
The XSV-300 board is a versatile FPGA development board providing a 300-Kgate FPGA, programmable clock oscillators, standard PC interface components (e.g. a USB-Transceiver), Flash memory, RAM and 7-segment displays.
USB-power Dual-voltage regulator
This Design Idea stems from the limited availability of IC voltage regulators that can meet key USB-power specs, coupled with the need for turn-on sequencing and rise-time control at each output. As always, for PC-related designs, minimum cost is a primary motivation. USB specs require all loads to limit inrush current to less than 100 mA plus...
USB Power Management with LTC3455
The LTC3455 seamlessly manages power flow between an AC adapter, USB cable and Li-ion battery, while complying with USB power standards, all from a 4mm ½§ 4mm QFN package. In addtion, two high efficiency synchronous buck converters generate low voltage rails which most USB-powered peripherals require.
Car PC MP3 Player
This is a computer I built for my car, its an MP3 music system but can also do other tasks. Based around a super-small sub-micro ATX motherboard from a computer known as the BookPC BKi810, I have put the motherboard, hard drive, and a 12 volt power supply in a small case that fits under the seat of my car. Total size is approximately 11 x 8 x 2...
Pic-plot2: a GPIB to USB converter
This adaptor will capture plots or prints of your GPIB instrument to your PC through the USB port. It fills the need of anybody who has a test instrument with the GPIB port and likes to get the screen dump on his PC without any GPIB card or complex software. USB Self-powered from host PC.
USB Single Cell Charger
Lithium Polymer Batteries are a very common source of power today. Many electronics gadgets have one inside, and they have some reasonable features. I've bought great batteries, with different sizes and capacities for my electronics projects. So long I'm using this batteries, coming the problem: charge them.
USB Sound Card
The core of this construction is 16-Bit Stereo Digital-To-Analog Convertor with USB interface PCM2702. PCM2702 needs only few additional parts to work. The schematic is not complex. Sound card can be powered directly from USB port (jumper W1) or from external power supply (jumper W3). PCM2702 needs two power supply 3.3V (3V-3.6V) and 5V...
USB Development Board
A little board with most of Microchip kit, but less parts then all these boards. Only the basic components to get the microcontroller up and running the Microchip USB Library examples. PIC18F14K50 is a really basic device and after some research I found what you can do and what you can not do with it: What you can do: USB HID (Human Interface...
Breadboard header for ATTiny
This handy breadboard header for ATTiny 25/45/85 microcontroller is a new design based on the original idea from Tinkerlog. Maybe the most useful feature is that it can provide power to the vertical breadboard strips while connecting all six port pins to the horizontal strips. Other features are :6-pin ISP connector (works great with USBtinyISP...
Wireless XBee Accelerometer
The present document shows step by step how to easily build an interesting pointing device: the wireless tilt mouse, that allows to control the mouse?s cursor on the PC screen through the tilt of the board itself. The analog data from a 3-D accelerometer and from two push-buttons are acquired, converted and radio transmitted by an XBee module...
USB Printer Chooser Switch
With a DPDT switch, I can switch the two data lines. I tried connecting the shields from the two computers together, the grounds two computers together, switching the D+ and D- lines with the DPDT switch, and leaving the VBus lines float, but for some reason it didn't work. The Lexmark printer seemed to need to see the +5 Volts. It had been many...
USB sound card with PCM2702
If you use great IC PCM2702 from BURR BROWN / Texas Instruments you can create a fully functional USB sound card. This sound card can be powered from USB port and has one stereo output. You don’t need to install any driver for Windows XP and Vista, because they are already inside. This is really plug and play. The core of this construction is...
USB powered LED
This is a simple LED circuit that takes power from the USB port. I needed this USB light since long time ago but, finally; I was able to build it. The circuit schematic is so simple: Just one resistor and one White LED. I did use a 10,000mcd white LED. It illuminates perfectly the keyboard of my computer. In fact; it is so bright that, I can use...
USB selector switch
To share a regional press like the USB printer, scanner etc. two computers, it is relatively easy. Just connect the two computers on a network device and say the printer as shared. This method however requires the continued operation of the computer we plugged the printer. Solution to above problem is to give the circuit that we present, and has...
LCD to USB interface
LCD2USB is a open source/open hardware project. The goal of LCD2USB is to connect HD44780 based text LCD displays to various PCs via USB. LCD2USB was meant to be cheap and to be made of easily available parts. It is therefore based on the Atmel AVR Mega8 CPU and does not require any difficult to obtain parts like separate USB controllers and the...
i2c interface to USB interface
The i2c-tiny-usb project is an open source/open hardware project. The goal of i2c-tiny-usb is to provide a cheap generic i2c interface to be attached to the usb. It is meant as a replacement for those simple and cheap printer port to i2c adapters. A USB solution has several advantages incl. the built-in power supply and a more future proof...
Acceleration sensing USB interface
The TiltStick is a small acceleration sensing device in form of a USB stick. It's using a two axis acceleration sensor to measure acceleration (caused e.g. by motion and tilt). The device is emulating a USB joystick and can thus be used in conjunction with any USB equipped host (e.g. a standard PC or the Nokia N8XX family) without any special...
USB demo board
USB AVR In-System-Programmer (ISP)
Nowadays, USBis the most popular connection connection between PC and peripherals such as AVR programmers, printers, scanners etc. For that reason I had to modify my old serial AVR In-System-Programmer (ISP) to work with USB connection. You can say, "use a USB to Serial adaptorto connect your AVR ISP with your PC". Yes, that could be a solution bu
8051 USB PROGRAMMER
The above circuit uses RS232 for interfacing with PC. It is very simple circuit & works very well with PC. Power is drawn from usb port OR needs external supply of 5V. The value of the crystal is very critical at AT89C2051 and must be 11. 0592MHz. Here AT89C2051 is loaded with firmware required for RS232 communication with PC. Assemble the...
Dual cable (serial + USB) for Nikon coolpixes
To assure that USB and serial segments are electrically isolated, we used an optocoupler (U1). The LED section of U1 is driven directly by DTR, so we should select a very sensitive optocoupler to prevent too much current flow from DTR (which is usually very limited, implementation-dependent; around 3 mA max. if we don't want to push the serial...
Connecting Nokia 3310 LCD to USB using AVR
What do you do with an old phone, a microcontroller and lots of time? You hook the old phone`s LCD screen to the computer USB of course.
i2c interface to usb interface using attiny45 microcontroller
Attach any I2C client chip (thermo sensors, AD converter, displays, relais driver, to your PC via USB quick, easy and cheap! Drivers for Linux, Windows.
Computer Interface Circuits
Ultrasonic distance finder circuit
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 measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
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 find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
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 circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
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 circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
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, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
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 calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
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 supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
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. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
DIY HV Variable Capacitor
DIY PMA Alternator Plans
Digital Signal Integrity