Weekly Elektor Wrap Up: Thermometer with Giant Display, AVR Software-Defined Radio Webinar, & More!

It’s time to review what our Elektor colleagues in The Netherlands, France, and beyond worked on and covered this week! As usual, they’ve been quite busy working in the Elektor lab, organizing webcasts, prepping for Design West, and assembling upcoming issues of Elektor magazine. The following is a wrap-up of some of the many things Elektor staffers covered and worked on this week.

Below is a video of a thermometer with a giant display.

The electromechanical display was recovered from a ’60s-era pinball machine.

The thermometer with a giant display

Using the display and some innovative programming techniques, it’s possible to build a water-temperature indicator a swimming pool. After the temperature appears on the 4″ reels, the circuit’s consumption decreases to zero. But the temperature display remains perfectly visible. You needn’t worry about batteries (dry or rechargeable), adjustments, or maintenance. (Published in Elektor issue 424, April 2012 www.elektor.com/110673)

Board for Elektor's thermometer with a giant display

On the event front, Elektor Academy and element14 have teamed up to bring you a series of exclusive webinars covering blockbuster projects from recent editions of Elektor magazine. Participation in these webinars is completely free! All you need to do is register via www.element14.com/community/events/3258. The “AVR Software-Defined Radio” webinar takes place Thursday, March 9, 2012. Click here for more information.

Elektor also reported some interesting electronics news this week. The items that will most interest Circuit Cellar readers are an Uninterruptible Power Supply in a Chip and a Python-Based Tool for Diagnosing Dead-Core Boards.

CircuitCellar.com is part of the Elektor group.

Electronics Engineering Crossword (Issue 261)

The answers to the crossword puzzle published in rCircuit Cellar 261, April 2012.


7. MANCHESTERENCODING—A form of BPSK [two words]

10. REBOOT—Restart

13. HASHTAG—The # label

15. DIRECTORY—File index

17. DAEMON—Takes place behind the scenes

18. FREEBASIC—Open-source programming language compiler

19. MALWARE—Bad code


1. PHASESHIFTKEYING—Transports data by altering a reference signal’s phase [three words]

2. FOURIERTRANSFORM—Changes a signal from the time domain to the frequency domain [two words]

3. ATTENUATON—Used to measure signal loss in dB

4. SHANNONTHEOREM—AKA, the noisy-channel coding theorem [two words]

5. BOOLEAN—Logic system named after George Boole

6. FREQUENCYMODULATION—Opposite of AM [two words]

8. COULOMBCOUNTER—Measures battery current [two words]

9. FOURTHGENERATION—4G [two words]

11. FIRSTQUARTILE—25th percentile [two words]

12. NORTONAMPLIFIER—Converts a current to a voltage. [two words]

14. HBRIDGE—Four switching components with the load in center

16. CODIFY—A way to organize

Issue 261: Cap-Touch Amp Design, RL78 Intro, Embedded Linux, & More

The April issue is now available. As usual, it comprises a wide variety of content: a capacitive-touch amplifier design, an intro to using the Renesas RL78 for low-power apps, info on sigma-delta modulators, Linux software development tools, mesh networking tips, an interview with Dave Jones (of The Amp Hour and EEVblog) and more.

One of Dave Jones's old projects from the '80s. It's a Veroboard construction with items from his junk bin (Source: D. Jones, CC261)

A portion of the PIC-based PodAmp schematic (Source: C. Denninger & J. Lichtenfeld, CC261)

You’ll also notice some changes this month to Circuit Cellar magazine and our website. They’re all for the better.

The magazine has an updated layout. We haven’t changed fonts or style, but we did add the imprint you can see on pages 6–7. Its purpose is to show you that we are an ever-growing international company dedicated to bringing you essential information on a variety of important advanced electronics topics.

I added our editorial calendar, as well as a brief summary of the content we have in queue, to page 2. The idea is to give you a clear idea of what we will cover and when you can expect it. Members frequently ask for this information, so it makes sense to make it easily accessible for everyone.

As for CircuitCellar.com, well, you’ve likely watched it change slowly over the past few months. We did this purposely. We developed the site in stages so readers wouldn’t be burdened with dead links and redirects. So, what’s new about the site?

The layout is a bit different. A few things are quickly apparent. One, the site is markedly brighter and easy on the eyes. Two, we created three distinct columns that provide you with easy access to handy articles, digital downloads, and more (see below). Three, we’re tagging and categorizing all the content on our site. Thus, you’ll find targeting specific information to be uncomplicated and immediately gratifying.

What sorts of content can you expect? The old site was fairly static. We’d make several changes each month and we’d run a few viewable articles. Now we’re constantly posting relevant content of all sorts. This means you can rely on CircuitCellar.com for all of your electronics engineering needs: DIY articles, engineering tips, industry news, product reviews, vendor information, issue previews, links to source code, and even job openings in electronics engineering and embedded design.

If you are constantly plugged in, you’ll find our website makes accessing your digital membership a cinch: just point and click to log in and download each issue! Plus, you can add our site to your RSS reader and read our content at your convenience (www.circuitcellar.com/feed/rss).

We are not finished building CircuitCellar.com. In the coming weeks and months, we’ll enable more social interaction, post more videos, and broaden our areas of coverage. I suggest you visit our site each day to get your fix of embedded technology news and info. And please recommend the site to colleagues, friends, and others who have a passion for microcontrollers, programming, and everything else that’s “inside the box.”


Build a CNC Panel Cutter Controller

Want a CNC panel cutter and controller for your lab, hackspace, or workspace? James Koehler of Canada built an NXP Semiconductors mbed-based system to control a three-axis milling machine, which he uses to cut panels for electronic equipment. You can customize one yourself.

Panel Cutter Controller (Source: James Koehler)

According to Koehler:

Modern electronic equipment often requires front panels with large cut-outs for LCD’s, for meters and, in general, openings more complicated than can be made with a drill. It is tedious to do this by hand and difficult to achieve a nice finished appearance. This controller allows it to be done simply, quickly and to be replicated exactly.

Koehler’s design is an interesting alternative to a PC program. The self-contained controller enables him to run a milling machine either manually or automatically (following a script) without having to clutter his workspace with a PC. It’s both effective and space-saving!

The Controller Setup (Source: James Koehler)

How does it work? The design controls three stepping motors.

The Complete System (Source: James Koehler)

Inside the controller are a power supply and a PCB, which carries the NXP mbed module plus the necessary interface circuitry and a socket for an SD card.

The Controller (Source: James Koehler)

Koehler explains:

In use, a piece of material for the panel is clamped onto the milling machine table and the cutting tool is moved to a starting position using the rotary encoders. Then the controller is switched to its ‘automatic’ mode and a script on the SD card is then followed to cut the panel. A very simple ‘language’ is used for the script; to go to any particular (x, y) position, to lift the cutting tool, to lower the cutting tool, to cut a rectangle of any dimension and to cut a circle of any dimension, etc. More complex instructions sequences such as those needed to cut the rectangular opening plus four mounting holes for a LCD are just combinations, called macros, of those simple instructions; every new device (meter mounting holes, LCD mounts, etc.) will have its own macro. The complete script for a particular panel can be any combination of simple commands plus macros. The milling machine, a Taig ‘micro mill’, with stepping motors is shown in Figure 2. In its ‘manual’ mode, the system can be used as a conventional three axis mill controlled via the rotary encoders. The absolute position of the cutting tool is displayed in units of either inches, mm or thousandths of an inch.

Click here to read Koehler’s project abstract. Click here to read his complete documentation PDF, which includes block diagrams, schematics, and more.

This project won Third Place in the 2010 NXP mbed Design Challenge and is posted as per the terms of the Challenge.



Read CircuitCellar.com for Updates/News from Design West, San Jose

Circuit Cellar and Elektor editors and staffers will attend Design West in San Jose, CA, from March 27 to 29. If you can’t make it to the conference, check www.CircuitCellar.com daily for conference updates, news, and more!

Feed the latest posts from CircuitCellar.com to your RSS reader! Doing so will keep you up-to-date on everything we post! Setting up the feed is simple.Add www.circuitcellar.com/feed/rss to your RSS reader and enjoy!

The Circuit Cellar/Elektor booth at ESC 2011 (San Jose, CA)

This year’s conference comprises seven summits at once: ESC, Android, Black Hat, DesignMED, LED, Sensors, and Multicore.

Members and clients are encouraged to stop by booth #2332 to chat with staff, subscribe to our magazines, grab free copies of the magazines, and check out our books. Readers should feel free to bring and pitch article proposals, book proposals, and project ideas!