After our recent post about the commercial semi-conductor tester we started a discussion about building a similar open source project. What came up is this AVR based transistor tester (machine translation) by Markus.
It’s built around an ATmega8 IC that interfaces with a standard HD44780 16×2 character LCD. The circuit that does the testing is simplicity itself. Three pairs of resistors are connected to 6 pins of the microcontroller, and each pair is connected on the other end to one of the transistor pins.
The theory of operation is also relatively simple. The microcontroller cycles through different patterns on its output pins until a recognizable pattern is read on its input pins. It supports a very large range of devices:
- NPN and PNP bipolar junction transistors.
- P and N channel, enhanced and D type mosfet transistors.
- P and N channel JFET transistors.
- Common anode and common cathode dual diodes.
- Two diodes in connected in anti-parallel or series configuration.
- Single diode.
AVR-based transitor tester - [Link]
From the Cambridge Digital Library – [via]
Cambridge University Library holds the largest and most important collection of the scientific works of Isaac Newton (1642-1727). We present here an initial selection of Newton’s manuscripts, concentrating on his mathematical work in the 1660s. Over the next few months we will be adding further works until the majority of our Newton Papers are available on this site.
Newton was closely associated with Cambridge. He came to the University as a student in 1661, graduating in 1665, and from 1669 to 1701 he held the Lucasian Chair of Mathematics. Under the regulations for this Chair, Newton was required to deposit copies of his lectures in the University Library. These, and some correspondence relating to the University, were assigned the classmarks Dd.4.18, Dd.9.46, Dd.9.67, Dd.9.68, and Mm.6.50.
Cambridge to put Isaac Newton Collection Online - [Link]
Last year, Texas Instruments (TI) released industry’s lowest cost (only $4.30) microcontroller development kit named Launchpad. It is a complete development tool for rapid prototyping with TI’s ultra-low power MSP430 Value Line MCUs. I also bought a Launchpad kit several months ago but haven’t really looked into it. Last weekend, I spent a couple of hours reading about the MSP-EXP430G2 experimenter board (that comes with the Launchpad kit) and the Code Composer Studio (CCS) software tool. CCS is an integrated development environment (IDE) to develop and debug applications for TI’s embedded processor families. As always, a “Hello World” program is the best thing to start with any new development platform. If you ran it successfully, it means you have setup the compiler and the programmer/debugger correctly and you are all set to go. Here’s a step-by-step guide to set up the CCS v4 build and debug environment for the MSP-EXP430G2 experimenter board.
Setting up the CCS v4 build and debug environment for TI MSP430 Launchpad - [Link]
Global online community element14 is dedicated to providing engineers with end-to-end resources and the latest technology to help get their jobs done faster and easier than ever before. Following are a few noteworthy additions to the community:
- CadSoft launches EAGLE version 6: The newest version of the award-winning PCB software, available via the element14 knode, not only helps in board design, but also saves engineers time by providing direct connections to experienced, high-quality PCB manufacturers for fast quotes on PCB fabrication. Plus, with Accelerated Design’s Ultra Librarian users can quickly create parts, symbols and footprints that can be exported to various PCB design flows. An introductory video is available for download here.
- element14 partners with PCB prototype manufacturer Screaming Circuits: Effective Dec. 13, 2011, design engineers using the Knode on element14 can access Screaming Circuits’ services, including instant quotes and efficiently produced high-quality prototypes that adhere to shorter design cycles, saving engineers countless resources and helping shave weeks off the design process
element14: CadSoft’s EAGLE version 6 now available & new supplier partnership in effect - [Link]
On my desktop PC I have a speakers and a headphones. Usually I use headphones, but when I need to switch to speakers I need to physically plug in speakers instead of headphones to my PC’s soundcard. I wanted to solve this problem for a long time, but never get around of that until recently I saw this posted on Hackaday.
And so I’ve decided to build my own really simple audio multiplexer.
USB Audio Multiplexer - [Link]
Festivize your bench this holiday season with an oscilloscope Christmas tree – [via]
When I was a little kid, my dad worked at Bell Labs. Every year around Christmas, we’d go visit him at work. One memory which has always stuck with me from my holiday visits was seeing a Christmas tree on an oscilloscope. I was pretty amazed by it. Engineers are a funny bunch — they tend to celebrate holidays in the most uniquely nerdy and wonderful ways, just like kids. When I recently acquired a new ‘scope and wanted to familiarize myself with it, I knew exactly what my test circuit was going to be.
In honor of the nameless BTL engineer whose scope scribbling captivated me as a child, here we are. Maybe the same thing will happen for some other kid. There are a lot of holiday parties coming up. You could put this on one of your scopes at work or at your hackerspace, and some other kid will see it, and it’ll fire their imagination too. It looks pretty neat at any rate, and it’s downright fascinating after a few fortified egg nogs.
Oscilloscope Christmas Tree - [Link]
Mini Thermal Receipt Printer – [via]
Add a mini printer to any microcontroller project with this very cute thermal printer. Thermal printers are also known as receipt printers, they’re what you get when you go to the ATM or grocery store. Now you can embed a little printer of your own into an enclosure. This printer is ideal for interfacing with a microcontroller, you simply need a 3.3V-5V TTL serial output from your microcontroller to print text, barcodes, bitmap graphics, even a QR code!
Mini Thermal Receipt Printer - [Link]
The Fritzmas challenge – send in your projects! @ Fritzing. Andre writes – [via]
It’s that time of the year again, and we would like to take the opportunity to re-cap what the last year has brought. So here’s the Fritzmas challenge 2011: You show us what you did, and we give you what we did.
How you can win
Take a look at what you’ve built with Fritzing this year, and snap a couple of photos/screenshots. If you think it’s an interesting concept, a technical masterpiece, or just fun, we want to see it all.
Then either upload it to our projects gallery or mail them to info (ät) fritzing.org. (Also, you must agree that we may publish what you send us (if you prefer, anonymized).
Deadline is Sunday, December 18th.
The Fritzmas challenge – send in your projects! – [Link]
Getting Started- Vacuum Fluorescent Display & Teensyduino | A work in progress…. [via]
This is a quick tutorial on getting a VFD working with an Arduino (or Arduino equivalent system). VFDs are beautiful devices with a wonderful hexagonal mesh of wires and this lovely green/blue glow. Operating at around 5V, they offer a nice alternative to high voltage Nixie tubes, while still retaining a lot of the charm.
This tutorial will show you how to connect a Arduino-like device to a VFD display as well as a basic program to display text.
Vacuum Fluorescent Display & Teensyduino - [Link]
via Google: – [via]
I still recall the day when my friend Yossi came to school and showed off his brand new graphing calculator. I was stunned by how easy it was to plot complicated functions — meanwhile, the rest of us were still drawing them by hand on graph paper.
Today, I’m hoping to share that magical feeling with students around the world, with the introduction of graphing functionality on Google. Now you can plot mathematical functions right on the search result page. Just type in a function and you’ll see an interactive graph on the top of the search results page.
You can zoom in and out and pan across the plane to explore the function in more detail. You can also draw multiple functions by separating them with commas. This feature covers an extensive range of single variable functions including trigonometric, exponential, logarithmic and their compositions, and is available in modern browsers.
I hope students and math lovers around the world find this experience as magical as I found the graphing calculator so long ago.
Google Enables Function Plotting from Search - [Link]