I have published a page on my Frankenrotator project, a cheap homebrew azimuth and elevation rotation system using a Yaesu rotator mated with a Radio Shack TV rotator.  The brain of the unit is an Arduino Mega and complete schematics are provided.


The project illustrates how to build a power supply for both DC and AC rotators, replacing commercial rotator controllers.  The main control unit powers and controls both rotators and interfaces to a computer using the Arduino native USB port.  Logging and control programs command the system via Yaesu GS-232B emulation.  The project also demonstrates the use of a remote slave microcontroller.  A small waterproof box located at the rotator senses azimuth and elevation.  The remote microcontroller is periodically queried by the master unit via a serial link.

I still have to build some antennas to rotate with this system, which I hope to complete before winter sets in here in Pennsylvania.  Hopefully I’ll get to chase some satellites in between ice fishing!


Recently it’s been quiet here on Radio Artisan and I’ve been somewhat absent on  The usual excuses apply, with work consuming most of my intellectual energy and time.  It’s unfortunate we have to work so hard to live and have some fun.  In this culture we seem to be on an endless treadmill that goes faster and faster, but goes nowhere.  But needless to say I’m still alive and have been actually doing some amateur radio stuff these days.

Daily I receive correspondence about my CW Keyer and Rotator Controller, most of it coming from Europe and Australia.  Originally with the Rotator Controller I just wanted to interface my Yaesu rotator to the computer, but it’s gone beyond the original scope with notes from folks interfacing homebrew rotators and some amateurs with really cool ideas.  I continue to write bug fixes and minor feature updates for the CW Keyer, which now has two parties offering hardware kits.

The main project garnering the most attention right now is the Arduino Antenna Tuner.  It’s going slower than anticipated, but I’m pleased to say I’ve been making some progress with a good portion of the tuning network built, the I2C interface hardware working, and the frequency counter prescaler built on the hardware prototype.  I’m currently working on an SWR bridge and I’m having some issues.  I’ve built a Bruene bridge and a Tandem Match bridge, and both have rather mediocre directivity, in the neighborhood of 12 to 14 dB.

Both of my SWR bridge prototypes are “good enough” to use for software coding and testing, however I want the final product to be better.  Any feedback from anyone with hands-on experience building SWR bridges would be appreciated.  Once I get the hardware prototype to a reasonable level, I can dive into the coding.  Some of this work was completed earlier this year as I wrote some SWR reading and calculation subroutines and some LCD interface code.  I’m really giddy to get coding. Although I really like building stuff I guess I’m more of a software guy than hardware.  I find algorithms, protocols, networking, and interfacing exciting.

I continue to enjoy working with folks, helping them get code working and talk about ideas.  It’s neat to be able to email someone halfway around the world a code snippet and have them load it up on their hardware, use it, and have fun with it.  Although the Internet has made the world seem smaller, and amateur radio is no longer the only way to talk to folks in far off lands, amateur radio adds another dimension to the Internet and vice versa giving us more opportunity to help each other and promote international goodwill.

Arduinos in Space and On The Air

Recently the Arduino has been making its way into the skies.  ArduSat is a project to build and launch an Arduino-powered satellite into space.  Here’s a video describing the project:

A little closer to Earth, Michael Doornbos, N4LNX and founder of Evadot, is working on an Arduino-based board for using in balloon payloads.  The unit is called FireFly and features wireless capabilities, a data acquisition and storage subsystem, and is solar power ready.  It’s intended to pack a lot of functionality in one easy-to-use unit and save time and effort for those building payload computers for high altitude balloon experiments.

Here’s a short video showing reception of data bursts from a FireFly on a Yaesu FT-857:

This project is really timely considering the recent increase in interest in balloon experiments in amateur radio.

What’s Ahead for Arduino

The Arduino project announced some news at MakerFaire 2011.  Here’s a video of a talk from Massimo Banzi:

In a nutshell, they are working on a new release of Arduino called “1.0” or the “1.0 Core” which is going to break some things, but also set the stage for a more consistent and stable platform going forward.  There are new hardware revisions for the Uno and Mega boards.  The most notable change with these boards is the addition of several pins to support a two wire interface (I2C) bus which will enable much easier and standardized interfacing to shields.  There is also a new Arduino that has an Ethernet interface built in, rather than having to use a separate Ethernet shield.  (Shields are optional boards you can stack on Arduinos for additional capabilities.)  I’m very interested in this board as it also has an SD slot for memory storage.  I’ve been toying with the idea of writing a logger module for the keyer project.  Why?  Because I can and it’s never been done :-)

The project is also releasing a WiFi shield which opens up a lot of possibilities.  Another dream geek project I’ve had has been to place Arduinos in various places throughout the house and the yard for doing various things like reporting the temperature or sensing intruders.  The Arduinos could network via WiFi and report to each other or back to the mothership.

All and all it’s an exciting time in Arduino land.  If you haven’t tried using one of these little boards, you’re missing out on some fun.  The applications in amateur radio are endless and with the power and functionality steadily increasing, I expect in a few years we’ll be doing things like DSP or perhaps have a rig-on-a-shield.

From the Workbench: Arduino CW Keyer

I’m pleased to announce my Arduino CW keyer code is ready for prime time and available for download here.  At first this started out as merely porting my PIC keyer code to the Arduino, but the advanced features and ease (and joy) of coding for this platform encouraged me to venture further.  Beyond my original PIC keyer features, this creation also has a speed potentiometer, a serial port command line interface, more and bigger memories, QRSS, HSCW, and memory macros.  It also has a callsign receive practice mode, CW keyboard, and Hellscreiber sending capability.  I’m trying to figure out a way to interface with Ham Radio Deluxe and N1MM, and I have in the works a frequency counter option for use within homebew rigs, like my original PIC keyer.

The code is stable at this point, and I’m not aware of any bugs.  If anyone tries this code out and has bug reports, feedback, or feature requests, please drop me a comment.  Next I’m going to finish the Yaesu rotator computer interface.

I have a lot of ideas for an Arduino controlled antenna tuner swimming around in my mind.  After having two commercial automatic antenna tuners that were disappointing, I think I can build a better mousetrap.  The tuner will be a balanced L design capable of 150 watts or more, but still capable and accurate at QRP power levels.

Fun stuff!