Digital Clock with Alarm using DS1307 DS1307 is a hardware realtime clock, which works on I2C protocol.  Better graphics using the same old fashioned alphanumeric LCD (type HD44780).  Icons which shows the status for Alarm ON/OFF state, which gives a nice and cute look to the clock.   __ Designed by Wichit Sirichote

Digital Electronic Lock The digital lock shown below uses 4 common logic ICs to allow controlling a relay by entering a 4 digit number on a keypad.  The first 4 outputs from the CD4017 decade counter (pins 3, 2, 4, 7) are gated __ Designed by Bill Bowden

Digital Volt & Amp Meter with Temperature Control This project was designed and constructed as enhancement to the 0-30V Stabilized Power Supply Project with the DIY electronics hobbyist in mind.  The circuit uses a single PIC Microchip to perform the Voltage, Current and Temperature conversions and display functions.  The PCB Board uses large  __ Designed by RSABear © 2008

Digithermo V1.0 Build a laboratory instrument that measures time and temperature.  A 89C4051 interfaces 16x1 line LCD, 3-digit DVM CA3162 and LM35D precision temperature sensor.  This device is capable of providing 0.1C readout.   __ Designed by Wichit Sirichote

Disassembler Takes On 8-Bit Intel µPs & µCs 11/10/94 EDN-Design Ideas The disassembler and documentation in the ZIPfile attached to EDN BBS /DI_SIG #1624 handles the object code for 8048, 8051, 8080, and 8085 family processors.   Design by K V Ramakrishnan, DRDO, NPOL Cochin,  Kerala, India

Disk Drives at 40: Lean Mean Storage Machines 11/07/96 EDN-Design Feature    System designers who need disk drives for projects ranging from compact embedded systems to multiprocessor enterprise servers need to take a close look at the latest offerings from drive vendors.  Sure, the drives store more and cost less than they did last year, but new products feature entirely new interfaces, form factors, and recording technologies, of which designers need to be aware.   Design by Maury Wright

DisplayTech LCD interface Low cost LCD module interface with optional LED backlight __ Designed by Michel Bavin

Dive Computer Interface From the start, digital computers have required some form of data storage as an adjunct to their relatively sparse mainstorage facilities.  Some of the early forms of storage were punched cards, paper tape and the magnetic tape storage.  This was the principal storage medium,  __ Designed by shaunwilson19 @ yahoo.com

DIY HP-MSIB Cable Guide HP-MSIB cables, original or third-party, are now difficult to find and frequently for more money than the equipment to which they will be connected.  It seems HP used special controlled-impedance cables for their originals, but it turns that for reasonable-length runs, simple 50-pin twisted pair SCSI cable works just fine.  This is how I built mines __ Designed by Roberto Barrios EB4EQA

DIY Microphone Cable for iPod Touch (2nd Gen) Put together your own Y Splitter Adapter Mic/Speaker recording cable as shown in the circuit diagram below to use a PC Mic Headset with the iPod Touch (2nd Generation only) and iPhone.  

DIY Microphone Cable for iPod Touch (2nd Gen) Put together your own Y Splitter Adapter Mic/Speaker recording cable as shown in the circuit diagram below to use a PC Mic Headset with the iPod Touch (2nd Generation only) and iPhone.  

DIY Web Chat Hack Control home devices via the Internet. __ Contact: Jameco Electronics

DMA eases CPU's workload for waveform generation 12/05/05  EDN-Design Ideas Code uses the fewest cycles to implement periodic waveform with DACs Design by Mike Mitchell, Texas Instruments, Houston, TX

DMX PC Keyboard Interface This is the Design for a DMX512 to computer keyboard interface.  It sits in line on the computer keyboard and on the DMX 512 chain.  Decoding The Lighting data and ifone it's set channels is set above 1/2 value this unit will output a sequence of keyboard keys to the connected PC.   __ Designed by Paul Harris

Double DAC rate by using mixers as switches 5-Feb-04 EDN-Design Ideas You can effectively double the sample rate of a DAC by interleaving two DACs into a single unit.  Updating each DAC on an alternating basis and switching to the appropriate output double the effective throughput of the overall system.  It is essential to overall performance that you use a high-quality, high-speed switch in the multiplexing of the DACs' outputs Design by Randall Carver, Analog Devices, Greensboro, NC

Dreamcast Interface A simple circuit to connect the Dreamcast console to PC.  No MAXxxx IC required.  Only a few discrete components.  This circuit is a direct replica of the daVinci cradle schematic.  

Driving an LCD From the Parallel Port You build the module, then use the software to display messages of to program a thermometer/thermostat chip.__ SiliconChip

Driving LEDs In Parallel & Series using a PIC16c508 Scroll to find this circuit #6If a number of LEDs are required to be driven from a single output, you will need to connect them in parallel or series.  There are limitations, however, as you will see.  Firstly it is ok to connect two LEDs in series, provided you work out the value of the dropper resistor.   __ Contact: Colin Mitchell

Driving LEDs using a PIC16c508 Scroll to find this circuit #5Each output line of a '508A can only deliver about 25mA.  This current is determined by the size of the transistor delivering the current.  The transistor inside the chip is only very tiny and if a higher current is drawn, it may be damaged.   __ Contact: Colin Mitchell

Driving More Than 4 LEDs using a PIC16c508 Scroll to find this Circuit #7 -If more than 4 LEDs are required to be driven, a buffer transistor will be required as shown in fig: 12.  This transistor will allow the LEDs to be driven from a 12v supply (or higher) and the number of LEDs can be increased to 6 per column for 12v __ Contact: Colin Mitchell

DS1620 based USB Digital Thermometer I connected a DS1620 digital thermo-censor by Dallas Semiconductor to the Morphy Planning's USB-IO to build a PC-accessible digital thermometer.  The DS1620 chip supports 3-wire (SPI) protocol and allows loose timing, so you can easily build a thermometer with it.  It provides ¬0.5 centigrade accuracy, which should be sufficient for room temperature.   __ Contact: IQ Technologies

DS1621 PC thermometer This incredibly simple thermometer plugs on any free serial port.  Does not make use of any programmable components as microcontrollers.  It gives temperature readings accurate to 0.5°C with no calibration.  It's cheap, so I've put one on any PC I use.  And it is so nice to have the temperature shown on the Windows taskbar, that a million friends asked me to build one.   __ Contact: IQ Technologies

DS1820 PC Thermometer This is a digital thermometer based on USB PIC16C745 microcontroller from Microchip and DS1820 sensor from Dallas Semiconductor.  Temperature readings are sent over USB port in HIDCOMM USB mode to VB6 program on a PC.  Hex program and sample Visual Basic 6 application is included.  

DSL Filter (phone-line) The above diagram is a standard low-pass telephone line filter (L1, C1, L3, C2).  L2 and L4 are needed since we're dealing with the 'Tip' and 'Ring' of a phone line which may carry up to 90VAC! __ Designed by Tony van Roon  VA3AVR

DSP Chip Connects to ADC over Serial Port 02/01/96 EDN-Design Ideas A multichannel ADC interface for the ADSP-21xx Series of fixed-point DSP chips uses a MAX186 low-power, eight-channel, serial, 12-bit ADC.  This ADC has many features useful for low-power data-collection applications.  The device is a complete data-acquisition system with integrated T/H and internal reference.  You can use software to configure the analog inputs for unipolar/bipolar and single-ended/differential operation Design by   Dhananjay Gadre, Inter-University Centre of Astronomy and Asrophysics Pune, India

DTMF Dialer Coding Table A truth table for NS TP5088 DTMF tone dialer.   __ Designed by Wichit Sirichote

Dual Fan Controller Each fan turns off when the temperature drops 5 degrees below its turn-on temperature.  For example, if the dial is set to 80 degrees, the fan turns on at 80 degrees and turns off at 75 degrees.  This prevents the fan from cycling on and off rapidly, which would occur if the fan turned on at 80, started to cool the cabinet, and then immediately turned off at 79.  

Dual Regulators Power Pentium® Processor or Upgrade CPU DN122 Design Notes __ Linear Technology/Analog Devices

Dual-Phase High Efficiency Mobile CPU Power Supply Minimizes Size & Thermal Stress DN247 Design Notes__ Linear Technology/Analog Devices

Dual-voltage regulator meets USB-power needs 19-Aug-04 EDN-Design Ideas 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 50 µC of charge when powered on Design by Wayne Rewinkel, National Semiconductor, Phoenix, AZ

Dual-voltage supply powers SIM card 01/20/00  EDN-Design Ideas Global-system-for-mobile-communication phones have a subscriber-identification module (SIM) that allows local wireless providers to recognize the user and his or her billing information.  Although most SIMs are changing to 3V operation, they also accommodate 5V as well during the transition.   Design by Larry Suppan

Dynamic siphon steals current from USB port 12/15/06  EDN-Design Ideas Make maximum use of a USB port's current-delivery capability Design by Donald Schelle, Maxim Integrated Products Inc, Sunnyvale, CA