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R5000 Receiver Interface This circuit is a modified version of an original interface on QSL Net.  It is a fully isolated interface allowing computer control of the Trio/Kenwood R5000 receiver.  Separate software is needed to control the receiver.   __ Designed by Andy Collison

Radio Clock for PC's The heart of the device is a EM2S receiver module and matching antenna.  The two are matched, so a mixing a 60kHz receiver board suitable for the MSF and WWVB signals with a 77.5kHz antenna and vice versa will not work.  It should be noted that the receiver boards know nothing about the format of time signal itself so a 60kHz pair suitable for receiving the MSF signal will also receive the WWVB signal __ Designed by Jonathan A. Buzzard

Radio Interface Box for the Motorola Radius GP300 The Motorola Radius GP300 VHF or UHF handheld transceiver has a dedicated signal port on its back for programming it.  Lots of info on that subject can be found on the web, but although the circuit wasn´t complicated, I didn´t find a PCB layout for it.  I also wanted something to connect the RIB to the GP300 in a fast and easy way.  What I present here is the result of my work on this.   __ Designed by EB4EQA

RC5 Infrared Remote Control Receiver for Media Centers A few time ago I decided to create a media center box to replace my DVD player, satellite receiver, VCR and my kid's Play Station 2, to one device.  So, I made a core 2 duo processor system that actually replaced with succeed, all my electronic devices.  The only thing that was missing was a remote control to switch On/Off my Media Center.  After I searched on the net to buy a complete remote control system, I saw that the price was a little bit high (about 90 euros).  I checked my stuff to find my old 7-in-one remote control that I had bought 2 years ago and I started to build my own remote control receiver circuit.  

RDS Coder Board using ATmega32 This board is a RDS coder using an ATMEL AVR ATmega32.  This board can be controled by a RS232 link, USB interface or SPI.  TA data is displayed wiyth a LED and can be controled by :, Hardware input, RS232, USB, SPI (not yet implemented) 

Reading Data from the Parallel Port The diagram below shows 5 switches connected to the 5 input lines of the parallel port.  An external 5 volt power supply is used to provide high logic levels to the input pins when the switches are open.  Three 1.5 volt batteries in series can be used to obtain 4.5 volts which is close enough.  The 330 ohm resistors.   __ Designed by Bill Bowden

Reassembly of a "Dual Group" SKD-4000 laptop (~1MB) On occasions I dig out specimens from my collection of old computers and give them a spin.  Sometimes I find that they've thrown in the towel and demanded repair before delighting me with their operation, while other times I find that they've mysteriously resolved some issue that I couldn't be bothered fixing myself upon the time of my last attempted use. __ Designed by Kevin Koster

Rectifier tracks positive & negative peaks 06/08/06 EDN-Design Ideas Versatile precision rectifier also delivers full-wave output Design by Harry Bissell Jr

Regulator Generates Both 3.3V & 5V Outputs from 3.3V or 5V to Run Computers & RS-232 DN71 Design Notes__ Linear Technology/Analog Devices

Remote Relay Controller I reprogrammed the PIC inside the LDG DTS-6R remote antenna switch to control a 8-relay PCB I got from eBay.  I built a relay driver that talks to the remote controller via two-wire rs-232 serial interface.  It has a programmable default status so the required relay states appear at power-up.   __ Designed by Roberto Barrios EB4EQA

REMOTE[RS232] using Easy-Server V0.9 Experiment the microcontroller with internet server.  The Easy-Server provides simple means for connecting microcontroller through a 9600 8n1 serial interfacing.  Exemplary circuit using PIC16F84 for REMOTE RS232 and experiment description were included.   __ Designed by Wichit Sirichote

Reset Card Eases µP Troubleshooting 10/26/95 EDN-Design Ideas The circuit in Fig 1a generates repetitive system resets to 68XXX processors.  These resets allow you to troubleshoot power-up problems using a scope instead of a logic analyzer or storage scope.  This reset card, which you can build for less than $10, consists of a DIP switch, Design by Michael A Martone, Teleos Communications, Eatontown, NJ

Reset ICs create sequenced or long resets 11/20/97 EDN-Design Ideas Reset-generator ICs offer an inexpensive way to generate reliable reset signals for µC and µP applications.  Certain applications, such as multiple-processor systems, require multiple resets.    Design by Doug Anderson, Electronic Technology Corp, Ames, IA

Resistor implements half-duplex RS-232 with echo 11/24/99 EDN-Design Ideas A previous Design Ideas (" Single µC pin makes half-duplex RS-232 ," EDN, Aug 5, 1999, pg 118) presented a way to implement half-duplex RS-232 communications without echo.  Sometimes, an echo is desirable in aµC application.  You can obtain the echo by using a single resistor (Figure 1).  You insert a 5.1-kW resistor between the transmit and receive pins on the RS-232 driver (such as a MAX232).    Design by Matt Bennett

RJ45 Network Card to IR Communication This system, composed of two opto-insulated circuits, allows the data transmission per infra-red network device between two computers. For example, someone can transfer his files starting from his desktop computer to his laptop computer without using any cable. How? By using infra-red diodes __ Designed by Serge Saati

ROM Emulator This is a very simple ROM emulator.  It can only "Load and Run", because reduced unnecessary functions and reduced board size, so it is good for portable use.   __ Designed by The Electronic Lives Manufacturing-presented Chan

Routine Provides Four-COM-Port Recognition 02/01/96 EDN-Design Ideas In DOS-based computers with serial ports besIdeas COM1 and COM2, the DOS-booting process does not recognize the additional ports.  The BIOS RAM location00000411 holds (among other data]a 3-bit count of the number of installed serial Design by Tom Myers, Palo Alto, CA

RS232 Booster RS232 ports of modern laptops are not always complying with the original RS232 standard.  If RS232 levels are expected to be +/- 12 volts, most of the time laptops RS232 ports produce in fact +/- 5 volts levels.  For most peripherals, this is not an issue and they are responding as expected

RS-232 Data Switch In 1989, at university, after the success with submitting a writeup about my homemade 68008 single-board computer as a co-op work term report, I hatched the idea of building another piece of gear that I wanted anyway, and submitting it as an EE499 project.  EE499 was the course code __ Designed by Markus Wandel

RS232 DB-9 Switch Simple hardware expands COM1 to COM1/1 and COM1/2;  RS232 DB-9 Switch to Flip Between Two Serial Ports __ Designed by Wichit Sirichote

RS-232 dB-9 Switch-To-Flip Between Two Serial Ports got a problem with my notebook, because it has only COM1.  My programmer board, Easy-Downloader must use serial port and the application board also needs to communicate via the same serial port.  I do remembered I have to swap DB9 connector of both devices many times.  So I spent 30 minutes built above simple hardware.  Of course __ Designed by Wichit Sirichote

RS-232 Interfaces for 3.3V Systems DN75 Design Notes__ Linear Technology/Analog Devices

RS-232 Laser Transceiver Laser based projects used to be expensive, until the development of solid state lasers.  This project is designed for the entry level laser experimenter.  The circuit allows any two computers with serial (RS-232) communication capability to communicate over 200 meters using a laser beam.  A low cost transmitter only circuit is also presented here for use in one way communication and other laser based projects __ Designed by shaunwilson19 @ yahoo.com

RS232 Level Conversion RS232 Level conversion

RS-232 Line Monitor & Loopback Cables If you have problem with RS232 cabling, your best "emergency" tool may be a breakout box (sometimes called an LED box).  The normal units only come in the DB25 size, but with a couple of DB9 to DB25 adaptors, they can be used with DB9 cables as well.  The units have an LED for each signal line in the cable, and the LED lights green or red dependent on the signal state.  __ Airborn Electronics, Australia

RS-232 Overvoltage Protections RS-232C serial port lines are quite prone to be damaged by overvoltages.  The damaged to computer serial ports have become more and more expensive to replace because of higher intergaration: usually you have to buy new motherboard if one serial port in it gets broken.   So it is wise to use some extra protection in situations where overvoltages surges are quite propabe and repairing gets expensive.  For examples of this type of situations are long serial port lines side the building and situation where the computer is connected to ungrounded outlet or the electricity distribution wiring is is not well organized. __ Designed by Tomi Engdahl

RS-232 Protocol Analyser In need for a cheap but effective RS-232 Protocol Analyser? Just make your own Y adaptor to enable the logging or display of data transmitted and/or received in ASCII, Hex, Decimal or Hex-Dump formats.  A configuration file is included to allow quick setup and analysis. __ Designed by Craig Peacock

RS232 RS485 USB Converter Board Features:  for low traffic and low speed application;  mcu, RS232, RS485/RS422, slave usb all can be interchangeable;  usb side

RS-232 Serial Port Buffer This is a simple serial port buffer circuit I designed for a friend to speed up his SLIP connection in campus computer network "TRINET" of Helsinki University of Technology. The problem in the network was that the RS232 commections from rooms to terminal server were long and made of bad quality wiring. __ Designed by Tomi Engdahl

RS232 Serial Port PIC Programmer PIC Programmer is an essential tool if you wish to learn or build projects with Microchip PIC Micro Processors.  This programmer is built using Free Windows Software called WinPicProg and other similar software from PICALLW or Oshosoft 

RS232 Serial to USB Converter This is simple RS232 Serial to USB Converter that doesn’t need any further explanations.  You can use it for any projects that might need it.  Diagrams for USB and DB-9 female connectors are provided.