Bag of Beans » electronics

Mobius circuit board

Beanbag — Thu, 05 Feb 2009 00:42:16 +0000

A truly single-sided circuit board from Evil Mad Scientist Laboratories built on a Mobius strip with conductive ink.

In electronics, it is common to talk about single sided circuit boards. The most common type is a circuit board that only has printed wiring on one side, and components on the other side. There are also surface-mount boards, where all the wiring and components sit on one side. But aren’t all of those really just two-sided circuit boards where you only put components on one of the sides?

Here we present a method of making your own authentic single-sided circuit board.

Link

Magic-1 Homebrew CPU

Beanbag — Mon, 05 Nov 2007 06:09:53 +0000

Here’s another impressive homebrew computer. It was built with more than 200 ICs, and has similar capabilities to the original 8086 processor. It was recently demoed running a port of Minix 2.

Magic-1 is a completely homebuilt minicomputer. It doesn’t use an off-the-shelf microprocessor, but instead has a custom CPU made out of 74 Series TTL chips. Altogether there are more than 200 chips in Magic-1 connected together with thousands of individually wrapped wires. And, it works. Not only the hardware, but a full software stack. There’s a ANSI C cross-compiler for Magic-1 (retargeted LCC), a fully multi-user, multi-tasking port of the Minix 2 operating system. a TCP/IP stack and hundreds of programs.

Link (via Slashdot)
Article at LinuxDevices.com.

Related:

Stop using Ferric Chloride etchant! (A better etching solution.)

Beanbag — Tue, 04 Sep 2007 18:55:00 +0000

This instructable shows an alternative to etching PCBs with Ferric Chloride.

Ferric chloride is kinda nasty stuff. Quick to exhaust its etching power, non-reusable, kinda pricey, and ends up full of copper salts that are bad for the environment if you’re pouring them down the drain. (For instance: How to Dispose of Ferric Chloride in this FAQ. )

Wouldn’t it be nice if there were an etchant that you could re-use indefinitely so that you don’t have to worry about disposing of the copper, and that could be made in lifetime supply for like $10.00 with ingredients bought at hardware and drugstores? (And it’s prettier too.)

I got seven words for you: Copper Chloride in Aqueous Hydrochloric Acid Solution! (Exclamation point!)

Link

How-To: Make an Xbox 360 laptop (part 1)

Beanbag — Fri, 20 Apr 2007 05:07:42 +0000

Engadget has posted part 1 of a detailed how-to on converting an Xbox 360 into a laptop.

The making-of How-To for the Xbox 360 laptop will be in three parts. In today’s segment we’ll discuss the parts list, stripping down an Xbox 360 motherboard, and modding / reattaching the DVD and hard drives. The next installment will cover case design, construction and hacking the LCD display, as well as wiring the video. Part 3 will then describe wiring all the separate parts together, troubleshooting, and finishing up the unit.

Link

How-To: Make a solid-state A/V switcher

Beanbag — Tue, 20 Mar 2007 02:58:21 +0000

Engadget has posted a great how-to for building an A/V switch box.

While “solid state” may bring bring to mind electronics from the 60s (or, in some cases, yet-unreleased flash hard drives), but in this case it simply means the actual switching is done with circuitry, not mechanically. Ironically, the circuits are activated with a mechanical switch, but they could be controlled electronically if you were so inclined.

In this How-To we’ll show you how to wire up your own A/V switcher which you can expand and use any way you’d like, for composite, S-Sideo, component, even VGA signals. Sure, you can buy a newer, really expensive TV’s with multiple inputs (even component), but for those of us whose credit cards aren’t quite up to that challenge, more inputs for less cash would be rather desirable. Let’s get started!

Link

Color Codes

Beanbag — Fri, 23 Feb 2007 22:10:26 +0000

Link [xkcd.com]

DIY PIC based kitchen countdown timer

Beanbag — Wed, 06 Dec 2006 01:51:43 +0000

Here’s another PIC project, this time it’s a countdown timer. Hopefully, no one mistakes it for a bomb.

It’s a kitchen timer. Use it to time spaghetti, or maybe an egg. It uses two PICs, one acts as a keyboard encoder, the other drives the display and supports the timer functions. You key in the desired time and press ‘#’. It’s accurate to 1/100th of a second, which can make all the difference I’m sure you’ll agree.

Link (via MAKE: Blog)

DIY PIC Binary Clock

Beanbag — Wed, 06 Dec 2006 01:43:38 +0000

Walter Schreppers has built a nice binary clock controlled with a PIC 16F628 chip.

Link (via hack a day)

Make: The open source gift guide

Beanbag — Fri, 24 Nov 2006 08:10:55 +0000

Make Magazine has posted a great list of open source hardware and software for Makers.

There are hundreds of gift guides this holiday season filled with junk you can buy – but a lot of time you actually don’t own it, you can’t improve upon it, you can’t share it or make it better, you certainly can’t post the plans, schematics and source code either. We want to change that, we’ve put together our picks of interesting open source hardware projects, open source software, services and things that have the Maker-spirit of open source. Some are kits, some are open software projects that you’ll need to build hardware for before gifting, and some are just support for the projects/groups that do open source. Included in this guide are things you can get from the MAKE store too (we try and have as many open source goods as possible).

Link

Programmable Z80 Microcomputer

Beanbag — Tue, 21 Nov 2006 09:18:01 +0000

This is a fantastic homemade computer project. Look at the schematic for this thing. Yikes!

This is an actual computer, built completely from scratch. I began the project in the spring of 2006, while I was taking a course on microcomputers. My Z80 system will remain a work in progress as long as I can think of new things to add to it.

The current specs are:

2MHz 8 bit Zilog Z80 processor
56 KB static RAM (7 x 8k x 8 )
8 KB EEPROM
1 Mb Flash Memory “hard drive”
Interrupt controller with 8 interrupt levels
20 character x 2 line backlit LCD with contrast control
RS232 serial port
2 programmable timers
Programmable beeper
8X DIP switch and 8X LED’s for general purpose I/O
Strobe button for clocked input from the DIP switches
Parallel port programming interface with parity

…

I do all the programming on my PC, using Z80 assembly. I wrote a simple drag and drop utility in C++ that uploads the assembled code into the microcomputer’s memory.

Link (via MAKE: Blog)

Wacom Wax Off – DIY Cintiq build

Beanbag — Fri, 17 Nov 2006 00:21:28 +0000

Here’s an interesting write up for a project to build a Cintiq-like interactive pen tablet.

This is hybrid screen/graphics tablet which makes me drool. The price however makes me weep, Â£2000ish for the 20â€ version. They also do a thing called the PL at 17â€ for a more reasonable Â£500ish. Occasionally they appear on the site in their bargain basement ex-demo section. Still hard for me to justify though.

Then I had one of those â€œspangâ€ moments. None of the tech involved is new and all is readily available second hand, itâ€™s just a matter of putting it together. My Wacom at work will happily operate with the stylus off the surface, after that itâ€™s just an LCD screen, right? Anyhow whereâ€™s the fun in just buying something?

The finished product:

Link (via hack a day)

Ion Cooler 2.0

Beanbag — Fri, 03 Nov 2006 16:59:47 +0000

Inventgeek.com has made their own air ionizer to replace one of the case fans in their computer.

Due to popular request we have built this miniaturized ion cooler as a second step in its evaluation. We chose to use an external design for several reasons, all of which mitigate concerns from people on our initial prototype. One of the biggest concerns was with regards to the air moving threw the computer possibly having a imbalanced electrical charge or alternately producing to much ozone and possibly damaging components in the system. By mounting the unit at the rear of the case with it sucking air out of the case we are able to still achieve beneficial results and address these issues. The rig overall is basically the same as in the initial tests with one change that we used a more standard PC case with a normal 2 fan push pull type arrangement.

Link (via hack a day)

Building a Better Battery

Beanbag — Fri, 27 Oct 2006 01:25:40 +0000

Wired has posted an article that explains why lithium-ion batteries explode, and what might replace them in the future.

But such technical excuses sidestep the fact that flammability and heat intolerance are long-standing problems that have plagued Li-ion batteries since they were invented almost 30 years ago. And as devices have gotten smaller in size but richer in features, things have only worsened. Forced to produce more energy in less space, Li-ions die faster (as early iPod owners found when their batteries wore out long before their players did), and their propensity for thermal runaway greatly increases.

Link (via Digg)

DIY USB Alpha Radiation Visualizer

Beanbag — Mon, 14 Aug 2006 06:31:33 +0000

Inventgeek has a fascinating project that uses a webcam and a small radiation source from common household fire alarms to visualize radioactive decay. This could have applications as a source of entropy for a true random number generator.

I started this project with more of an idea of creating a system that would visualize Cherenkov radiation via webcam utilizing a Gamma radiation source and heavy water in some heavy lead shielding to produce the tell tale bursts of blue light. Perhaps hook it up to the LCD window kit system we did and display it on the windowed screen. When I decided to ramp up the project and also was experimenting with other types and sources of radiation for the project I stumbled across a myriad of new ideas for possible systems with some far reaching and profound results. While this write-up is just discussing in detail the implementation of this apparatus for ones personal amusement via screensaver, there are other far reaching possibilities for this system I will discuss later in the article.

Link (via Slashdot)

MintyBoost 2 AA USB Charger

Beanbag — Thu, 01 Jun 2006 03:20:42 +0000

Ladyada has a new howto on building a USB device charger based on two AA batteries, instead of previous, similar devices based on 9V batteries.

Another problem with the 9V+7805 scheme is that a 7805 is a linear regulator. That means if you want 100mA at 5V (basically, USB power) then you’re taking 100mA at 9V and then losing the 4V*100mA = 400mW (.4W) difference as heat. As the battery wears down to 7V the heat loss goes down to (7-5V)*100mA=.2W but you’re still getting bad efficiency. At best the efficiency is 72% (5V/7V) and at worst its 55% (5V/9V) That means you’re losing about a third of the battery power to heat!

Link to announcement
MintyBoost page
A copy of the tutorial has also been posted on Instructables.

Tic Tac Flashlight

Beanbag — Thu, 13 Apr 2006 02:33:22 +0000

Grynx has a simple project to build a LED flashlight using an empty Tic Tac box.

A disposable torch with long life (I hope I donâ€™t invent the wheel once more) I bought â€˜tic-tacâ€™ mint candy and found out that this package must be ideal for 3 AAA batteries to make a small torch (or lamp) with.
Yes the batteries fitted perfect – I soldered them in series and used a small micro switch from an old circuit-board together with an ultra bright white LED (25.000 mcd – 3,8 volt and 20 mA – 35 degrees) and a serial resistor of 27 ohm (to make it 3,8 Volt).

Link (vai MAKE: Blog)

HOW TO – Make a 12 foot GPS wall clock

Beanbag — Mon, 20 Mar 2006 07:20:08 +0000

Spark Fun Electronics has a put up a great howto on building a huge wall clock in their office. From MAKE: Blog:

Spark Fun Electronics writes – “Why? Well, why not? We had the new LED Light Bars burning a hole in our pocket, so we decided to build a clock. Not just any clock – but a very large 24″ tall, 12 foot wide, clock with GPS current time and accuracy down to 100ns. The clock turned into a huge undertaking. But at least we get to annoy Eric as the huge thing ticks over above his desk…”

Link (via MAKE: Blog)

Blink a LED

Beanbag — Sat, 11 Mar 2006 02:04:20 +0000

This page has some simple source files you can use to test various PICmicro controllers by making them blink a LED.

For non-embedded programmers the first thing to try on a new system or in a new programming language is to print out “hello world”. The equivalent for microcontrollers and other embedded systems is to blink a LED. When even the target circuit and the programmer are freshly put together it is wise to start even lower, with a blink-a-LED program written by someone else that is known to be working. Then when the LED does not blink (which is likely) there is one thing less to doubt about. On this page you will find 1 and 2 Hz blink-a-LED (and some other) test programs for various targets chips and circuits.

Link (via MAKE: Blog)

Ten most needed circuits for the DIYer

Beanbag — Wed, 21 Dec 2005 03:11:28 +0000

Some useful circuits for hobbyists.

I have decided to compile a list of the top ten most needed circuits that are a must know for anyone interested in DIY projects. These are the basics that can all be interchanged and used in conjunction with each other to make many of the projects that we all love so much.

Link

ATX -> Lab Bench Power Supply Conversion

Beanbag — Thu, 15 Dec 2005 18:50:21 +0000

Another article on how to convert an ATX power supply into a lab power supply, posted on instructables.

ATX -> Lab Bench Power Supply Conversion
Also posted by the author here, with some more pictures posted to flickr.