Lambic Keyer based on a PIC16F84 or PIC16C84 - This iambic keyer uses a PIC16C84 or PIC16F84 microcontroller to generate the dot/dash timing and key the transmitter.  Most modern rigs are keyed by grounding the key line.  The maximum current on the keying line is usually no more than a few mA.  If your transmitter has high voltage or high current on the keying line, you will need to use a relay to key the rig __ Designed by EI9GQ homebrew radio

LAN cable tester - Here's a very simple, but practical circuit, which is used to check the type of LAN cables  (straight or cross) as well as possible faults.  So we use a unit that has 8 outputs, each one of which produces a pulse successively. __ Designed by Vassilis Stergiopoulos ©

LCD clock based on AVR Attiny2313 - The clock is working a 24 hour period.  The time is displayed in the format "hh: mm: ss" on the alphanumeric display of size 16 x 2  (columns x rows) with driver HD44780.  The use of a backlit display gives the impression of great visual at night.  Instead, use a full stop or semicolon blink I used options available in the Bascom and created their own simple animation changing every second.  With such simple design to evaluate the accuracy of the clock is good.  Accuracy was +1 second / 48 hours.)  __ Designed by Szymon Dyja

LCD Terminal - The LCD Terminal just like a normal terminal, it can connect to any host via RS-232 serial cable.  A PC keyboard must connect to it as the input device and what ever you type will send to host via RS-232 and display on a 40x4 LCD.  Data receive from host can also display on the LCD unit.  You can use this device as any Unix/Linux machine's console.  

LCD Thermometer - 2nd version of Thermistor Thermometer __ Designed by Wichit Sirichote

LCD thermometer - In this page, I introduce the LCD thermometer which is sold by "Akizuki Denshi Tsusho".  At this thermometer, the IC thermo sensor  (S8100) or the diode  (1S1588) is used as the thermo sensor.  When using the IC thermo sensor, the thermometry to +100°C from -40°C is possible.  Also, when using the diode, the measurement to +150°C from -20°C is possible.  Both sensors are contained in the kit.   __ Designed by Seiichi Inoue

LCD thermometer using PIC16F871 - Build your own temperature meter for fun.  This project uses the Microchip TC77 digital temperature sensor,  a PIC16F871 microcontroller and a 7-segment 3˝ digit LCD.  You can study the source code on how to drive an LCD display.   __ Designed by Peter Jakab

LCD2USB. Part 1 - Overview 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 __ Designed by Till Harbaum

LCD2USB. Part 2 - Uploading the firmware If you are familiar with Atmel programming you probably know what you are doing.  The Makefile in lcd2USB/firmware/Makefile assumes, that you are using a simple STK200 compatible printer port adapter.  Connect the __ Designed by Till Harbaum

Lead-Acid Battery Zapper - This simple circuit is designed to extend the working life of liquid-electrolyte lead-acid batteries, by dissolving the lead-sulphate crystals which form on their plates.  It's powered by the battery itself  (or by a charger) and "zaps" the battery with a series of high-voltage pulses.__ SiliconChip

Lead-Acid Battery Zapper & Desulphator Mk.3 - Here is a revised version of the popular Lead-Acid Battery Zapper featured in the May 2006 issue of SILICON CHIP.  It is now separate from the Battery Condition Checker and much easier to build.  At the same time it has been revamped for more reliable long-period operation with 6V, 12V & 24V batteries.__ SiliconChip

Lead-Acid/SLA Battery Condition Checker - In July 2009 we presented an improved version of the Battery Zapper & Desulphator.  Here we present the companion Battery Condition Checker.  It gives more stable readings for all three main battery voltages  (6V, 12V & 24V) than our earlier model, as well as giving a choice of test current pulse levels to suit batteries of different capacities.  As a result, it?s now also suitable for testing sealed lead acid  (SLA) batteries.__ SiliconChip

LED & Push Button On One Line using a PIC16c508 - Scroll to find this circuit # 2 - In this book, we show how to connect two and up to five or more push buttons on a single input line and generally you will not have any problems adding buttons to a project.  But if you want to add a secret reset button  (or a "cheat" button, for example) , it can be added across an existing LED as shown in fig: 3.   __ Contact: Colin Mitchell

LED 7 segment Count Down Alarm - Here I have added two fets for the time-out switch, it is like an electronic relay, just much more reliable it can be used to sound a big horn, or what ever you like. __ Designed by Thomas Scherrer OZ2CPU

LED bargraph ammeter for your car - It's easy to build and even easier to connect.__ SiliconChip

LED Binary Calculator - You can't calculate binary values as is on most handheld calculators and using the windows one is just a pain, so i decided to make my very own  (binary only) calculator.  This calculator supports all the basic functions like : NOT, OR, AND, XOR, 

LED Blinking for Embedded Systems - Smart hardware design can simplify the embedded software and make it more reliable.  Designers use blinking LED signals to indicate different status and for inbuilt testability.  Making an LED array blink...__ Electronics Projects for You

LED counter - This circuit is the 12-bit binary counter which used 4040B.  The number of the pulses of the input can be confirmed by seeing it with the eyes by putting the light-emitting diode to the output of the counter.  It is the function only of it but it is useful.  Because it is the 12 bits, the highest rank counter __ Designed by Seiichi Inoue

LED driver provides oscillator for microcontroller - 16-Sep-04 EDN-Design Ideas - The major building blocks for a white-LED driver are an oscillator, a charge pump, and a regulated current source.  National Semiconductor (www.national.com ] produces a device that contains all these building blocks in the highly integrated LM2791/2 IC.  You usually use white-LED drivers in tandem with cellular baseband controllers or microcontrollers Design by Wallace Ly, National Semiconductor, Santa Clara, CA

LED driver provides software-controlled intensity - 09/30/04  EDN-Design Ideas - Recent advances in operating efficiency have expanded the use of LEDs from one of mere indicators to becoming driving forces in electronic lighting.  Increased reliability and ruggedness  (versus other lighting technologies] gives the Design by Neda Shahi and Bjorn Starmark, Maxim Integrated Products, Sunnyvale, CA

LED flasher - I made LED flash circuit which is often used as the PIC software making practice.  This circuit controls the blink of eight LEDs with the software of PIC.  The blinking pattern can be changed with five switches -- PIC16F84A __ Designed by Seiichi Inoue

LED Flasher - LED flasher with the LM3909 IC and runs from1.5-Volt battery.   __ Designed by Tony van Roon  VA3AVR

LED flasher 2 - This flasher moves, while lighting of LED drags on.  The brightness of LED is four kinds, bright, less bright, almost dim and dim.  These lighting states are moved with time.  Control of brightness is performed in lighting time of LED like PWM  (Pulse Width Modulation) .  There is no PWM function in PIC16F84A __ Designed by Seiichi Inoue

LED Lighting Effects - The original yoyo was equiped with 2 LEDs that lit up whendevice was spinning.  I decided to add a micro to give it some extra pazazz.  The trick here is to makeunit work without a power switch.  The mercury switch is positioned so that it supplies power whenunit is spinning.  After about 20 seconds, PIC shuts down in sleep modes,  __ Designed by Luhan Monat-Mesa Arizona

LED Strobe - This circuit drives a high brightness LED as a strobe.  The BD136  (I had one spare) transistor can be used to drive an LED from a higher voltage source than the PIC operates from if required.   __ Contact: P. Townshend - EduTek Ltd

LED Strobe & Contactless Tachometer - This versatile LED Strobe & Tachometer can be used to observe and measure the RPM of rotating machinery.  It offers three different measurement methods and the readout is via a 2-line LCD module.__ SiliconChip

Led Strobe & Tacho Pt.2 - Last month, we published the circuit of our new LED Strobe & Tachometer and showed how to build the main unit and the strobe light.  This month, we describe the assembly of the optional Photo-Interruptor and IR Reflector Amplifier boards.  We also describe how the unit is used.__ SiliconChip

Let's Get Quizzical: a Quiz Game with a Difference - No more boring old buzzers for us...__ SiliconChip

Level meter for home theatre systems - Having trouble adjusting the levels in your home theatre system? This simple project makes the job easy.__ SiliconChip

LF LowFER Beacon Transmitter - Here's a complete LF Beacon transmitter for LowFER    (Low-Frequency Experimental Radio) .  The transmitter is designed for license-free operation between 160 kHz and 190 kHz, consuming the legal limit of 1 watt power input to the final RF output stage.  For fun, the complete transmitter is built into an Altoids mint tin.  The circuit is built dead-bug style on a piece of copper clad circuit borad material, lightly painted with Testors transparent Hot Rod Red to prevent tarnish.  The paint doesn't seem to make soldering any more difficult.  The board is grounded to the tin in a few places.   __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Light Controller - On this page, I will introduce the Light controller with PIC16F873.  This circuit is usable only in the direct electric current.  It isn't possible to use for alternating current.  In this circuit, the following features of PIC16F873 are used.   __ Designed by Seiichi Inoue

Lightning shutter trigger for a camera using an Arduino - I knew there were devices that could trigger a camera to fire during a lightning strike, but their circuits were more complicated than I wanted to make.  I’m a software guy not a hardware guy so I decided to use an Arduino and that allowed me to write a little code that made the circuit much simpler. __ Designed by Ravi Upadhyaya

Li-Ion Charger - PIC Project  Lithium Ion batteries pack a lot of power by weight compared to other types.  There are 2 things that need to be handled differently than NiCad on NiMH : __ Designed by Luhan Monat - Mesa Arizona