ESP32 Drives Tiny FM Radio

September 14, 2023 by 21 Comments

Even as music streaming services and podcast apps dominate most of our listening time, it’s still a great idea to keep a radio on hand, if for nothing else than in emergency situations. After all, blizzards, hurricanes, and other natural disasters can quickly take out both home and mobile Internet access. If you’d like to have an FM radio with the absolute smallest footprint, take a look at this one built around an ESP32.

While the radio uses the ESP32 as the main control board hosted by a TTGO T-Display board which adds a 1.14 inch ST7789V IPS panel, it also makes use of the TEA5767 chip for handling the FM radio signals. As [Volos Projects] has it programmed, the ESP32 stores five preset channels which can be toggled using two buttons at the bottom of the device. There’s also some circuitry to handle output to headphones or a stereo.

For making the radio even smaller, some of the audio processing could be done on the ESP32 instead, although its much simpler to take a slightly larger footprint and offload this to an audio processing chip. Since the source code for this project is open, modifications could be done including adding seek/tune functionality instead of relying only on presets. If you’re not building this for emergencies, though, and your entire area is dominated by cookie cutter corporate-owned radio stations, an ESP32 with an internet connection is great for accessing better radio stations around the world.

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Balloon-Eye View Via Ham Radio

September 11, 2023 by 22 Comments

If you’ve ever thought about launching a high-altitude balloon, there’s much to consider. One of the things is how do you stream video down so that you — and others — can enjoy the fruits of your labor? You’ll find advice on that and more in a recent post from [scd31]. You’ll at least enjoy the real-time video recorded from the launch that you can see below.

The video is encoded with a Raspberry Pi 4 using H264. The MPEG-TS stream feeds down using 70 cm ham radio gear. If you are interested in this sort of thing, software, including flight and ground code, is on the Internet. There is software for the Pi, an STM32, plus the packages you’ll need for the ground side.

We love high-altitude balloons here at Hackaday. San Francisco High Altitude Ballooning (SF-HAB) launched a pair during last year’s Supercon, which attendees were able to track online. We don’t suggest you try to put a crew onboard, but there’s a long and dangerous history of people who did.

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Will RadioShack Return?

September 8, 2023 by 146 Comments

We suspect that if you want to write a blockbuster movie or novel, the wrong approach is to go to a studio or publisher and say, “I have this totally new idea that is like nothing you’ve ever seen before…” Even Star Trek was pitched to the network as “Wagon Train to the stars.” People with big money tend to want to bet on things that have succeeded before, which is why so many movies are either remakes or Star Trek XXII: The Search for 4 PM Dinner Specials. Maybe that’s what the El Salvador-based Unicomer Group had in mind when they bought one of our favorite brands, RadioShack. They are reportedly planning a major comeback for the beleaguered brand both online and in the physical world.

In all fairness, the Shack may be better in our memories than in our realities. It was handy to stop off and pick up a coax connector, even if it cost three times the going rate for one. There was a time when RadioShack offered reasonable parts for projects, and it seems like near the end, they tried to hit that target again, but for many years, you could not find the typical parts for a modern project there anyway. However, Unicomer isn’t just a random group of investors.

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Transistor Radio Repair, More Complex Than It Seems

September 7, 2023 by 48 Comments

The humble transistor radio is one of those consumer devices that stubbornly refuses to go away, but it’s fair to say that it’s not the mover and shaker in the world of electronics it might once have been. Thus it’s also not a staple of the repair bench anymore, where fixing a pocket radio might have been all in a day’s work decades ago now they’re a rare sight. [David Tipton] has a Philips radio from we’re guessing the later half of the 1960s which didn’t work, and we’re along for the ride as he takes us through its repair.

It’s an extremely conventional design of the era, with a self-oscillating mixer, 455 kHz IF amplifier, and class AB audio amplifier. The devices are a little archaic by today’s standards, with comically low-gain germanium transistors and passives from the Ark. Injecting a signal reveals that the various stages all work, but that mixer isn’t oscillating. A lot of fault-finding ensues, and perhaps with a little bit of embarrassment, he eventually discovers a blob of solder shorting a collector resistor to ground. All isn’t over though, for the volume pot is also kaput. Who knew that the track from a modern component could be transplanted into one from the 1960s?

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USB-C Power For Ham Radio

September 5, 2023 by 28 Comments

Even though manufacturers of handheld ham radios have been busy adding all sorts of bells and whistles into their portable offerings, for some reason, many of them lack a modern USB-C port. In the same vein, while some have USB for programming or otherwise communicating between the radio and a computer, very few can use USB for power. Instead , they rely on barrel jacks or antiquated charging cradles. If you’d like to modernize your handheld radio’s power source, take a look at what [jephthai] did to his Yaesu.

In the past, USB ports could be simply soldered onto a wire and used to power basically anything that took 5 VDC. But the radio in question needs 12 volts, so the key was to find a USB-C cable with the built-in electronics to negotiate the right amount of power from USB-PD devices. For this one, [jephthai] cut the barrel connector off his radio’s power supply and spliced in some Anderson power pole connectors so he could use either the standard radio charger or one spliced onto this special cable.

With this fairly simple modification out of the way, it’s possible to power the handheld radio for long outings with the proper USB battery bank on hand. For plenty of situations this is much preferable to toting around a 12 V battery, which was the method of choice for powering things like QRP rigs when operating off-grid.

Polish Railways Fall Victim To Cheap Radio Attack

August 29, 2023 by 41 Comments

Poland’s railways have recently come under a form of electronic attack, as reported by Wired. The attack has widely been called a “cyber-attack” in the mainstream media, but the incident was altogether a more simple affair pursued via good old analog radio.

The attacks were simple in nature. As outlined in an EU technical document, Poland’s railways use a RADIOSTOP system based on analog radio signals at around 150 MHz. Transmitting a basic tone sequence will trigger any duly equipped trains receiving the signal to engage emergency braking. It’s implemented as part of the PKP radio system on the Polish railway network. Continue reading “Polish Railways Fall Victim To Cheap Radio Attack” →

Off-Grid Radio Also Repairable Off-Grid

August 19, 2023 by 30 Comments

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 [Dr. Daniel Marks] 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.

Thanks to [Stephen Walters] for the tip.