Hobby DIY Electronics

An Amateur Radio Enthusiast from Brazil. JK De Marco. In these pages Hams will find his ideas on QRP, Antennas and Complete circuits.

PY2WM JK De Marco Projects

“One test result is worth a thousand expert opinions”. This has been attributed to a range of people, but most authoritatively to Wernher von Braun, the rocket scientist.

A 40 dB RF Attenuator - "To measure power of a high power transmitter, or to be able to observe the output signal on an oscilloscope or spectrum analyzer, it is necessary that the signal is attenuated in accordance with the instrument, while it must be ensured that the transmitter is "seeing" the correct impedance. So it requires an attenuator that works with three ports (input, output, and output attenuated), all while maintaining the correct impedance of 50 ohms.

The circuit assembly and is shown here in EMRFD and also in the QST. When properly calibrated can be used for precision measurements in section 0-500 MHz, or a a calibration capacitor C1, can be used for the range of 0-50 MHz with reliability."

Other Projects and Ideas

• Simple Homebrew Coil Winding Machine
• Qrp-Br Spectrometer
• Simple ESR meter
• Swr Power Measuring mW To KW
• 5 Volts Reference Voltage Calibrator

The following is my Computer Science project Comp490 and Comp492 in progress. It is a SUMO robot for our local RoboWar tournament. I have been, for the pass two years a participant of the annual RoboWar competition. So, this year I've decided to try to get credit for doing it.

Read more »

This is a nice educational reference project based on 89C2051, an 8051 derivative. This uses the Uses analog switches to steer test tones and results. Programmed in assembler to produce pure 1khz tone. 

Tone generation using 89C2051 -  AirBorn



Using a multimeter

"The example meter that we are demonstrating is typical of many economical digital multimeters that you can purchase, hopefully these instructions will be of some use to you no matter what brand or type of meter you use. "

My Notes

Students and Hobbyists can study all the example projects and tutors in this site to become more skillful. They have pages that show how a PCB is made and things like Circuit Design and Prototyping. This Site also happens to be one of the oldest resources in the web for Electronic Embedded Designs.

Mitch Altman, president and founder, invented the company's hit product TV-B-Gone® and turned the product into an international success practically overnight.

Cornfield Electronics - Mitch Altman

Solder your ArduTouch kit together, and it works! You can make way wonderful music, sound, and noise.

Use the ArduTouch Library or hack the existing sketches to create your own cool synthesizers.
The documentation is getting good enough to learn how to use Digital Signal Processing (DSP) to make your own sounds for your own projects.

Cornfield Electronics, Inc.
1800 Market St. #123 San Francisco, CA 94102, USA

usbtiny - Software USB implementation

USBtiny is a software implementation of the USB low-speed protocol for the Atmel ATtiny microcontrollers. Of course, it will also work on the ATmega series. The software is written for an AVR clocked at 12 MHz. At this frequency, each bit on the USB bus takes 8 clock cycles, and with a lot of trickery, it is possible to decode and encode the USB waveforms by software.

 Other Atmel AVR Projects he built are

• batwatch - Monitor for a solar panel car battery charger 
• webasto - Remote control of Webasto water heater
• blink -  Automatic turn signal light
• nikon- Nikon Camera Remote Control

Projects of Dick Streefland from De Bilt

Dick Streefland, lives in Amersfoort, in the center of The Netherlands. He has some Atmel AVR Projects and he is a big fan of Linux. He started on a 6809-based home-brew system with the OS9 operating system from Microware.