Posts with «ham» label

Off-Grid Radio Also Repairable Off-Grid

Low-power radios, often referred to in the amateur radio community as QRP radios, have experienced a resurgence in popularity lately. Blame it on certain parts of the hobby become more popular, like Parks on the Air (POTA) or Summits on the Air (SOTA). These are events where a radio operator operates off-grid at remote parks or mountaintops. These QRP rigs are a practical and portable way to make contacts. You would think that a five- or ten-watt rig running on batteries would be simple. Surprisingly, they can be enormously complex and expensive. That’s why [Stephen] built the RFBitBanger, a QRP radio designed to not only be usable off-grid but to be built and maintained off-grid as well.

The radio accomplishes this goal by being built out of as many standard off-the-shelf components as possible. It eschews modern surface-mount components in favor of the much more accessible through-hole parts, including the ATMEGA328P at the center of the build. A PCB design is also available, but it can be built on perf board nearly as easily. The radio supports any mode a QRP operator might use, including CW, SSB, RTTY, and a new mode designed explicitly for this radio called SCAMP which is a low bandwidth, low SNR digital mode built into the Arduino-based firmware. It’s a single-band radio, but any band between 20 and 80 meters can be selected with pluggable filters.

As far as bomb-proof radios go, we can’t imagine a better way to live out an apocalypse than with a radio like this. As long as there’s a well-stocked parts drawer around, this radio could theoretically reach around the world without worrying about warranty claims, expensive parts, or even a company going out of business or not stocking parts for old radios anymore. There’s also more information about this build at the Open Research Institute for those interested. And, if you’re wondering how useful any radio could be using only five watts of transmitter power, take a look at this in-depth look at QRP radio operation.

Bringing a Baofeng into the Cyberpunk 2077 Universe

You’ve got to love the aesthetics of dystopian cyberpunk video games, where all the technology looks like it’s cobbled together from cast-off bits of the old world’s remains. Kudos go to those who attempt to recreate these virtual props and bring them into the real world, but our highest praise goes to those who not only make a game-realistic version of a prop, but make it actually work.

Take the Nokota Manufacturing radio from Cyberpunk 2077, for instance. [Taylor] took one look at that and knew it would be the perfect vessel for a Baofeng UV-5R, the dual-band transceiver that amateur radio operators love to hate. The idea is to strip the PCB out of a Baofeng — no worries, the things cost like $25 — and install it in a game-accurate 3D printed case. But this is far from just a case mod, since [Taylor]’s goal is to replace the radio’s original controls with something closer to what’s in the game.

To that end, [Taylor] is spinning up an interface to the stock radio’s keypad using some 7400-series bilateral analog switches. Hooked to the keypad contacts and controlled by a Mini MEGA 2560 microcontroller, the interface is able to send macros that imitate the keypresses necessary to change frequencies and control the radio’s settings, plus display the results on the yellow OLED screen that seems a dead-ringer for the in-game display. The video below shows some early testing of the interface.

While very much still a work in progress, we’ve been following [Taylor]’s project for a week or so and he’s really gaining some ground. We’ve encouraged him to enter this one in the Cyberdeck Challenge we’ve got going on now; it might not have much “deck” going for it, but it sure does have a lot of “cyber.”

Converting Morse Code to Text with Arduino

Morse code used to be widely used around the globe. Before voice transmissions were possible over radio, Morse code was all the rage. Nowadays, it’s been replaced with more sophisticated technologies that allow us to transmit voice, or data much faster and more efficiently. You don’t even need to know Morse code to get an amateur radio license any more. That doesn’t mean that Morse code is dead, though. There are still plenty of hobbyists out there practicing for the fun of it.

[Dan] decided to take a shortcut and use some modern technology to make it easier to translate Morse code back into readable text. His project log is a good example of the natural progression we all make when we are learning something new. He started out with an Arduino and a simple microphone. He wrote a basic sketch to read the input from the microphone and output the perceived volume over a Serial monitor as a series of asterisks. The more asterisks, the louder the signal. He calibrated the system so that a quiet room would read zero.

He found that while this worked, the Arduino was so fast that it detected very short pulses that the human ear could not detect. This would throw off his readings and needed to be smoothed out. If you are familiar with button debouncing then you get the idea. He ended up just averaging a few samples at a time, which worked out nicely.

The next iteration of the software added the ability to detect each legitimate beep from the Morse code signal. He cleared away anything too short. The result was a series of long and short chains of asterisks, representing long or short beeps. The third iteration translated these chains into dots and dashes. This version could also detect longer pauses between words to make things more readable.

Finally, [Dan] added a sort of lookup table to translate the dots and dashes back into ASCII characters. Now he can rest easy while the Arduino does all of the hard work. If you’re wondering why anyone would want to learn Morse code these days, it’s still a very simple way for humans to communicate long distances without the aid of a computer.


Filed under: Arduino Hacks