Coprolite Homebrew Computer Construction and Electronics

The first microcontroller I became fascinated with was the 8048 (and 8748). This site has a lot of info on the 8048, including an 8048 Development System.

Coprolite Homebrew Computer Construction

From Hyper Embedded - Microcontroller ASIC and EDA

8048 The One who started it all ….

The roadside attraction of this site is the Z-80 Homebrew Computer. This was a project that I started in 1980. I moved many, many times between 1983 and 1996, and the project often was shut up in a trunk. In some cases I lost (or gave away) most of my equipment and parts. I finally got the full homebrew computer working twelve years later on several breadboards, and soldered it all up in 1993. It took me another ten years to document the system. It has been a fun ride.

DDDAC 2000 – Audiophile projects

DDDAC 2000 - Audiophile projects

Dedicated Website for Audiophile projects, such as a Diy High End DACs, Loudspeakers, Tube Amplifiers - Doede Douma

• Setting up an Audio Streaming Server (for use with the DDDAC1543 MK2 - USB)
• Gydinel, the Loudspeaker Master Reference ……
• Something completely different: Building your own Home Cinema !!!

TUMOS, the MOSFET Power Amplifier with real Tube sound!

"The DIY of designing and building of your own equipment is not only very satisfying as hobby on itself, but it will save you money, which you can invest in better parts used or parts you cannot build yourself like Turntables, cartridges etc."

Doede Douma

Maplin - Electronic Components and Tools

Computers and Electrical Spares and Tools. Hobby Gear & Electronics Materials. Educational Kits, Electronic Parts or Components. Cables and Wire management. Consumer Entertainment Electronics. Solar and Alternative Energy Kits.

Maplin - Electronic Components and Tools

Microcontroller-based function generator capable of producing square, sine, sawtooth or triangle waves. The wave shape and frequency are adjustable via on-board push buttons.

Function Generator Kit

Uses three IR diodes Eyes to find its way around. Six legged self-assembly kit, with a choice of rolling or walking legs.

Dallas Personal Robotics Group - DPRG

Articles, Photo Gallery, Projects, RoboLinks, Tutorials, Here you can share and exchange solutions and ideas about the exquisite art of Robot Design and Building.

Dallas Personal Robotics Group - DPRG

DPRG members have created some tips and howto for the common issues faced by robot builders.

DPRG Projects

After 7 years in the Garland warehouse, the DPRG is searching for a new home. The new plan is to try the hackerspace model, combining grants, donations, and membership fees to fund a fully equipped community workshop.

Establishing a Dallas Maker Space

Every robot needs sensors of some type to interact with the world around it. Infrared LEDs and Infrared photo detectors are one way to detect objects, but they are easily foiled by surrounding ambient light.

IR Proximity Detector by Jeff Koenig, August 1998


"Proximity sensors are commonly used on mobile robots for obstacle avoidance. This article presents a simple PIC-based, modulated infrared proximity sensor with dual angled transmitters and single receiver."

From Hobby Hound - DIY Electronics

Ron of DPRG is using the "Rarey Technique" for Taming a Wild Robot that went Berserk. ;-)

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.


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.

High Resistance Meter

I don't remember if this circuit worked properly. But a few were made and i might not have shown the modifications that were done to make it work. This was meant to be a portable, low cost, insulation tester for an electrician. If you try it out and debug it it may work well.

A negative voltage is derived by shifting gnd with two diodes, i feel this did not work very well. Two pins of CD4028 pins are also used to boost the reference to get two extra ranges as 4051 has a 100E on resistance.

From Schematics of delabs

The 555 clock makes 4029 counter count. But the clock can be clamped to gnd by a TL062 window comparator. The clock is frozen when the input value to comparator pin 5-2 is within a lower limit and upper limit "window" pin 3-6.

The 4029 counter BCD is decoded to decimal by 4028 which drives the LEDs, keep LED drive within 3mA or chip will be loaded. Use high efficiency extra-bright LEDs.

The 4029 BCD also controls a shunt resistor array with CMOS switches 4051. The voltage across shunt is a sample of leakage current. This is compared in the window comparator to freeze the Clock and LED display to give a reading of the leakage current or Insulation Resistance.

Advanced Reading

• Integrated Circuits
• pin connection diagram
• Dual Low-Power JFET-Input GP OpAmp
• Voltage Comparator Information
• Window Comparator Circuits
• TeraOhmmeter

Electronic Crafts - HandMade Electronics

"What happens when designers and makers look under the hood of the technologies that surround them and get their hands dirty with hardware and electronics?

This series of objects are the results of research in making our own electronic products while mixing in all sort of other crafts and technologies."

Electronic Crafts - HandMade Electronics

Plug in a solar cell or use the hand crank to create your personal source of power. The latest version of the PPP charges 9V batteries.

Mini power plant for small projects

How to make your own Hand powered shake LED flashlight.