Hobby Hound

Practical Electronics Learning with DIY. Practical Experiments forge the book, college or web learning into a Skill.

Search This Blog

Saturday, September 05, 2020

PJ Tool & Supply - Papa John’s Toolbox

They have unique variety of  tools for professionals, hobbyists, and do-it-yourself enthusiasts.The Business started 50 years ago by buying and selling of surplus merchandise from the US Military

PJ Tool & Supply - Papa John’s Toolbox

The Helping Hands magnifier is a great hands free device for holding small items in a fixed position for soldering and other intricate work.

Helping Hands Magnifier

Helping Hands Magnifier

PJ Tool & Supply
40-H Corbin Ave. Bay Shore, NY 11706, USA

Thursday, September 03, 2020

Step Down Capacitor - No Heat

Sometime in the eighties, I had to change a blind timer design due to non-availability of a component. A high resistance relay 600 ohm coil was not in supply, 150E was available. The Power to timer was derived from a resistor, I put a 0.47uF 630V and it Worked !. This design of mine, deriving a low voltage from a capacitor shown on right adaptation became popular. I used a 0.47uF 440V AC or 630V DC Plastic Capacitor.

This circuit has been drawn from my memory and i have not tried it out again, just see if it is ok and then try. You should use the fuse of 100mA a slow blow if you want but it is very important. This circuit has to be enclosed in a plastic sealed enclosure to avoid contact.

Mains Voltage Indicator with a LED
Mains Voltage LED Indicator

Tuesday, September 01, 2020

Cornfield Electronics - Mitch Altman

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.

Cornfield Electronics - Mitch Altman

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

Thursday, August 13, 2020

Beetle Robot guided by Light

First have a look at this How to Build a Robot a BeetleBot. This sparked the long lost memory of a book i read around 35 years back. My age was in single digits. This was when i had neither an idea of electronics or could afford any parts.

I had built many physics projects like weighing scale, gramophone, telegraph system, crystal radio. I will try to explain these later. Calling bells, gears and magnets from the flea markets my source of electricity & magnetism.

Beetle Robot guided by Light

I read a hobby book from UK for children. It was a Beetle Car Bot, with four wheels and 4 light sensors. It could be LDR or photo-transistors, i do not remember. The light sensors were at the four corners of the car. The maneuvering was by variation in the speed of each wheel. It was based on germanium transistors mostly.

Four large lamps like 40W, had to be mounted on the ceiling, at the four corners of the room. By turning on and off these lights, this bot could go anywhere in the room. The whole book with pictures was dedicated to one bot and how-to build one.

Now that we have PIC and AVR; we can use Dimmable LED Lightning arrays to guide the bot. The challenge is in the mechanics of the bot, we have to forget that we have wireless for some time. Try this out.

Friday, August 07, 2020

GainClone Chipamp Audio Amplifier

Gainclone or chipamp is a type of audio amplifier made by do-it-yourselfers, or individuals interested in DIY audio. It is a design based on high-power integrated circuits, particularly the National Semiconductor Overture series.

GainClone Chipamp Audio Amplifier

The Gainclone is probably the most commonly built and well-known amplifier project amongst hobbyists. It is simple to build and involves only a few readily accessible, inexpensive parts. As an amplifier it is highly regarded by many in the DIY community.

GainClone Chipamp Audio Amplifier

GainClone Amplifier Rod Elliott (ESP)

"The amp is based on the Project 19 PCB, so uses a pair of LM3876 (or LM3886) power opamps, run from a ±35V supply. ...........The power supply is conventional in almost all respects. I used a 160VA transformer, a 400V 35A bridge rectifier, and a total of 20,000uF per supply rail - 4 x 10,000uF caps in all."

Recording Technology History

1877 - Edison made the first recording of a human voice ("Mary had a little lamb") on the first tinfoil cylinder phonograph Dec. 6 (the word "Halloo" may have been recorded in July on an early paper model derived from his 1876 telegraph repeater) and filed for an American patent

Dec. 24. John Kruesi built this first practical machine Dec. 1-6 from a sketch given to him by Edison that was made Nov. 29 (not on "Aug. 12" that Edison mistakenly wrote on another sketch in 1917).

Recording Technology History - https://www.aes.org/aeshc/

Edison Phonograph

When Kruesi heard Edison's first words Dec. 6, he exclaimed "Gott in Himmel!" (but these words for "God in Heaven" were not recorded and thus have been forgotten). Others before Edison had tried to record sound, but Edison and his tinfoil phonograph were the first to succeed.

History of sound recording

The phonograph expanded on the principles of the phonautograph. Perfected by Thomas Edison in 1878, the phonograph was a device with a cylinder covered with an impressionable material such as tin foil, lead, or wax on which a stylus etched grooves.

Friday, July 10, 2020

DIY Radio Control Electronic Projects

This project, called "Simple-Timer" is a programmable Timer and electronic switch with an integrated LiPo Battery Monitor that is based around a PIC microcontroller.


The "Simple-Timer" includes a fairly accurate timer that is programmable (via pushbutton) by the user and can be programmed to time a 5, 10, 15, 20,25 or 30 minute event. When the timer/switch is enabled (tap small pushbutton), the onboard LED indicates the output is active by lighting solid (the circuit also outputs the same voltage as your supply/battery voltage using a PN2222 NPN transistor or a high current MOSFET).

Tom's Home Automation with X-10 Schematics Collection

    Electronix Express - For Schools and Industry

    Distributor of electronic components, test equipment and tools. Custom electronics kitting and value-added services. -  https://www.elexp.com/

    Electronix Express - For Schools and Industry

    Some of the products they supply include Anti Static Products, Toolkits, Soldering related, Inductors, Logic Probes and Pulsers.

    A Benchtop Multimeter,  4 ¾ digit, 40,000 count true RMS AC with Built-in USB & RS232 Interfaces.

    Bench Digital Multimeter DM422B

    Bench Digital Multimeter DM422B

    Other features -• Data save and recall with software, Triple display, (main, sub-left, sub-right), 40 segment bar graph display, duty cycle, Temperature function.....

    True RMS, USB & RS232 Model

    Electronix Express
    900 Hart Street Rahway, NJ 07065, USA