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A long, long time ago a bright ape figured out that by climbing down from the trees he could more easily master his life, and that of others……Homo sapiens wanted something else, and better. He started to play. Homo ludens was born!

Homo sapiens to Homo Ludens

  • Homo ludens radiactivus – amateur radio
  • Homo ludens radiohistoricus my antique radio collection
  • Homo ludens electronicus – electronic projects
  • Homo ludens aeromodellisticus – model airplanes

Transformers and coils: This is not a building project, but a short and concise lesson in how to design electromagnetic parts. It’s much simpler than what you may expect!

A 40 meter SSB QRP transceiver

A 40 meter SSB QRP transceiver

“This transceiver was conceived as a power-efficient, small, lighweight unit to be carried in the backpack, along with antenna and battery, for use during trekking and mountaineering trips. It had to be reasonably rugged and reliable, and perform well. Furthermore, I wanted it to solve all the problems the old DSB transceivers had, such as frequency instability, distorted modulation, lack of sensitivity and selectivity, and others.”

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This site’s purpose is to address the lack of technical information for some of the rarer vintage computers and related peripherals, with a strong focus on SWTPC.

Radio-Electronics and Popular Electronics – SWTPC

More than 600 pages of assembly instructions, schematics, program listings, catalogs, photos and much, much more! – Bill’s Knowledge Base, Michael Holley’s massive SWTPC doc collection.

Radio-Electronics and Popular Electronics

Popular Electronics was created in 1954 by Ziff-Davis Publishing for an audience of  electronics hobbyists and experimenters. It soon became the “World’s Largest-Selling Electronics Magazine”. The circulation was 240,000 by 1957 and exceeded 400,000 by 1963. Rival “Electronics World” was merged into “Popular Electronics” in 1972.

Radio Electronics was the “new” name for Radio Craft magazine.. Hugo Gernsback, sometimes called The Father of Science Fiction, started it as Radio-Craft in July 1929. The title was changed to Radio-Electronics in October 1948. In July of 1992 transitioned to “Electronics Now”.

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“I present, below, a collection of projects I have worked-on over the past few years. For over a decade, I had taught both embedded systems (microcontroller technology) and digital signal processing and practice what I preach….”

Professor Mark Csele – Projects and Hobbies

Nixie Thermostat – A heating and cooling thermostat employing technologies spanning fourty years from the unique Nixie tube display, circa 1960’s, to a PIC 18F microcontroller, circa 2006.

A High-Powered Power Backup Inverter

A High-Powered Power Backup Inverter – The working prototype of the 2 KVA inverter is complete. Fed from an array of lead-acid cells totalling 600 Ah (at 12 Volts), it easily drives real-world loads such as single-phase motors. The inverter has been tested and found to operate at an efficiency of between 71% and 82% driving a variety of both inductive and resistive loads

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It’s a 360 degree multifunctional programmable sensor that has a bundle of cool features for sensing for your Maker, Robot and Kinetic art type projects.

Infrared Control Freak 360 - ROBOTmaker

The sensors is also packed with two ambient light sensors (for light tracking experiments or line following) and IR remote control functionality so it can can read and transmit Sony SIRC IR control signals.

Infrared Control Freak 360 –  ROBOTmaker

The sensor is designed to fit onto micro sized robots (50mm x 50mm) where 360 degrees of proximity sensing, ambient light sensing and basic inter-robot communication is required, such as robot swarms, robot research, robot gaming and robot sumo competitions.

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Termite is an easy to use and easy to configure RS232 terminal. It uses an interface similar to that of “messenger” or “chat” programs, with a large window that contains all received data and an edit line for typing in strings to transmit.

Termite Terminal – RS232 Interfacing – CompuPhase

Plug-in interface for pre-processing or alternative views of the data, logging received data to a file, adding a toolbar to Termite, and other functionality that you may think of.

Termite Terminal

It can also do ..

  • A history of commands that you typed, with auto-completion.
  • Support for non-standard Baud rates (MIDI, DMX512).
  • Data can be forwarded between two RS232 ports.

The free Hyperterminal seemed to be missing, Now new and better feature rich terminals are available – Here’s one from CompuPhase who are our kind of people the EE kind. This terminal ought to help serial port SBC development.

PuTTY is a client program for the SSH, Telnet and Rlogin network protocols.

Realterm is a terminal program specially designed for capturing, controlling and debugging binary and other difficult data streams.

Realterm terminal program

Serial terminal program partcularly targeted at binary and difficult data 1) binary data, and debugging difficult communications problems. 2) use as a comms component for other s/w via full activeX interface Support for physical comm ports, and TCP

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The only way to improve the reception of FM-signals or particularly of stereo FM-signals under disadvantageous receiving conditions is to amplify the antenna signal. This should be made directly at the antenna, since the loss is increased meter by meter of any cable. In most cases higher line attenuations can be expected than usually calculated. Even receivers with an additional noise figure of zero do not show any improvements of the signal-to-noise ratio becomes too low because of a long transmission line. Therefore it is practically useless to require extremely low noise figures only for the receivers.

To avoid interferences of signals received from stations of other bands it is propitious to amplify the FM-band only. The band amplifier shown in Fig. 1.3 is connected directly to the 60 ohm output of the FM-antenna, i. e. it is placed at the top of the antenna pole. The matching is achieved by the input band-pass connected to the base of transistor BFT12, being a typically linear silicon transistor for broadband amplifiers. The output filter matched accordingly to a 60 ohm coaxial line is connected to the collector. The operating voltage of 15 V can be supplied by the coaxial line.

Fig. 1.3

Antenna-amplifier with BFT 12 for FM-range

Technical data:

  • Power gain Gp = 22 db
  • Noise figure F = 3.5-4.0 db or 2.2-2.5 KT0
  • Input and output reflexion coefficient |r1| and |r0| <= 0.3
  • dim(60db) at Vout = 680 mV
  • dim(50db) at Vout = 1000 mV

Optimum operating point of minimum intermodulation

Ic =~ 80 mA Vce =~ 7-7.5 V
Supply voltage 15 V

Coil data:

Vogt coil former, ordering code: Sp 3.5/16.6-2048C
Core: U17

  • L1 : 5 turns Cu 0.6 mm \o
  • L2 : 3 turns Cu 0.6 mm \o
  • L3 : 3+2 turns Cu 0.6 mm \o

Choke Ch1 = Ch2: 20 turns Cu L 0.3 mm \o, cross section of winding = 4 mm

Credits –

Antenna-amplifier with BFT 12 for FM-range
 from Design Examples of Semiconductor Devices – Siemens

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This is one IC that is like a E-LEGO, this along with Op-Amps and other components can make many interesting projects. Probably the very first Datasheet and Application Note of 555 t he e-lego.

Signetics made the 555,  On some pins like Control Voltage it responds to analog signals and on Reset and Output the signals are Digital like. The 7555 a CMOS version consumes lower power and oscillates at higher frequencies.

NE555 Applications and Specifications

555 trigger voltage cartoon

This evergreen or perennial chip is the favorite among students and hobbyists who want to learn electronics. Here is an original datasheet from Signetics i found online, it has very nice illustrations which will act as an appetizer for learning this science.

I want students to look into these specs pages as it will make your study more invigorating

555 Timer based Circuits – delabs

Signetics made the 555, This is one IC that is like a E-LEGO, this along with Op-Amps and other components can make…

555 The most Incredible Chip

Create an innovative 555 design today, the 555 should be the heart of the circuit. Here are some pages having 555…