fm radio

28 Articles

Art Deco Radio Gets FM Reception

April 7, 2018 by 12 Comments

Taking a vintage radio and cramming it full of modern, Internet-connected, guts has long been a staple of the hacking and making scene. While some might see it as a crime to take what’s arguably a legitimate piece of history and turn it into nothing more than a slipshod case for the Raspberry Pi, we have to admit there’s a certain appeal to the idea. Taking the beauty of classic design and pairing it with more modern capabilities is getting the best of both worlds.

But this project by [Nick Koumaris] is a somewhat unique take on the concept. Rather than sacrificing a real vintage piece of hardware to house the electronics, he’s designed a 3D printable case that looks like a classic 1936 AWA Radiolette. But what’s really interesting to us is that he then puts a basic FM radio inside of it.

That’s right, no Internet radio streaming or smartphone Bluetooth compatibility here. It’s just a regular FM radio, not entirely unlike the kind of hardware you’d expect to be inside of a classic radio. Of course, it’s much more modern, and [Nick] actually built it himself from a TEA5767 FM radio module and an Arduino Pro Mini.

While functionally it might not be terribly exciting, we do appreciate that he went through the trouble to make a vintage-looking user interface for the radio. While physical buttons would arguably have been more appropriate given the era, the art deco inspired font and graphics that show on the device’s Nokia 5110 LCD do look really slick.

Purists will surely be happy to see another project where a piece of vintage piece of audio equipment wasn’t sacrificed at the Altar of Hack, but we’ve also played host to many projects which weren’t nearly as concerned with historical preservation.

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34C3: Microphone Bugs

January 1, 2018 by 32 Comments

Inspiration can come from many places. When [Veronica Valeros] and [Sebastian Garcia] from the MatesLab Hackerspace in Argentina learned that it took [Ai Weiwei] four years to discover his home had been bugged, they decided to have a closer look into some standard audio surveillance devices. Feeling there’s a shortage of research on the subject inside the community, they took matters in their own hands, and presented the outcome in their Spy vs. Spy: A modern study of microphone bugs operation and detection talk at 34C3. You can find the slides here, and their white paper here.

Focusing their research primarily on FM radio transmitter devices, [Veronica] and [Sebastian] start off with some historical examples, and the development of such devices — nowadays available off-the-shelf for little money. While these devices may be shrugged off as a relic of Soviet era spy fiction and tools of analog times, the easy availability and usage still keeps them relevant today. They conclude their research with a game of Hide and Seek as real life experiment, using regular store-bought transmitters.

An undertaking like this would not be complete without the RTL-SDR dongle, so [Sebastian] developed the Salamandra Spy Microphone Detection Tool as alternative for ready-made detection devices. Using the dongle’s power levels, Salamandra detects and locates the presence of potential transmitters, keeping track of all findings. If you’re interested in some of the earliest and most technologically fascinating covert listening devices, there is no better example than Theremin’s bug.

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FM Snake Feeds Off Radio Waves

October 2, 2017 by 54 Comments

[Eric Brasseur] built a radio-detecting snake that consists of a LED that lights up when around reasonably strong radio waves. Near an FM radio mast you’ll find a huge amount of waste energy being dumped out in the 88 to 108 MHz range.

[Eric]’s rig consists of a pair of 1N6263 Schottky diodes, flip-flopped with one set of ends soldered to the antenna and the other ends soldered to the leads of the LED with about a foot of wire in between. The antenna can be a single wire as the diodes are soldered together. This one is around 4 feet in length for a total length of around 160 cm or a little over 5 feet. He went with a red LED just to give it a greater chance of being seen when illuminated by a distant or weak source of radio waves.

Hackaday loves its radio hacks; check out our posts on improving WiFi throughput with FM radio and building a modern DIY FM radio.

[Thanks, Alain!]

Decoding NRSC-5 With SDR To Get In Your Car

June 21, 2017 by 14 Comments

NRSC-5 is a high-definition radio standard, used primarily in the United States. It allows for digital and analog transmissions to share the original FM bandwidth allocations. Theori are a cybersecurity research startup in the US, and have set out to build a receiver that can capture and decode these signals for research purposes, and documented it online.

Their research began on the NRSC website, where the NRSC-5 standard is documented, however the team notes that the audio compression details are conspicuously missing. They then step through the physical layer, multiplexing layer, and finally the application layer, taking apart the standard piece by piece. This all culminates in the group’s development of an open-source receiver for NRSC-5 that works with RTL-SDR – perhaps the most ubiquitous SDR platform in the world. 

The group’s primary interest in NRSC-5 is its presence in cars as a part of in-car entertainment systems. As NRSC-5 allows data to be transmitted in various formats, the group suspects there may be security implications for vehicles that do not securely process this data — getting inside your car through the entertainment system by sending bad ID3 tags, for instance. We look forward to seeing results of this ongoing research.

[Thanks to Gary McMaster for the tip!]

Modern DIY FM Radio

March 22, 2017 by 20 Comments

Back in the day, building a DIY radio was fun! We only had to get our hands at a germanium diode, make some coils, and with a resistor and long wire as an antenna maybe we could get some sound out of those old white earplugs. That was back then. Now we have things like the Si4703 FM tuner chip that can tune in FM radio in the 76–108 MHz range, comes with integrated AGC and AFC, controlled by I2C, as well as a bunch of other acronyms which seem to make the whole DIY radio-building process outdated. The challenges of the past resulted in the proven solutions of the present in which we build upon.

This little project by [Patrick Müller] is a modern radio DIY tutorial. With an Arduino Nano as the brains and controller for an Si4703 breakout board, he builds a completely functional and portable FM radio. A small OLED display lets the user see audio volume, frequency, selected station and still has space left to show the current available battery voltage. It has volume control, radio station seek, and four buttons that allows quick access to memorized stations. The source code shows how it is possible to control the Si4703 FM tuner chip to suit your needs.

As for ICs, not everything is new, [Patrick] still used the good old LM386 amp to drive the speaker, which is almost 35 years old by now. As we can listen in the demo video, it can still output some seriously loud music sounds!

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PCB Design Guidelines To Minimize RF Transmissions

January 26, 2017 by 79 Comments

There are certain design guidelines for PCBs that don’t make a lot of sense, and practices that seem excessive and unnecessary. Often these are motivated by the black magic that is RF transmission. This is either an unfortunate and unintended consequence of electronic circuits, or a magical and useful feature of them, and a lot of design time goes into reducing or removing these effects or tuning them.

You’re wondering how important this is for your projects and whether you should worry about unintentional radiated emissions. On the Baddeley scale of importance:

  • Pffffft – You’re building a one-off project that uses battery power and a single microcontroller with a few GPIO. Basically all your Arduino projects and around-the-house fun.
  • Meh – You’re building a one-off that plugs into a wall or has an intentional radio on board — a run-of-the-mill IoT thingamajig. Or you’re selling a product that is battery powered but doesn’t intentionally transmit anything.
  • Yeeeaaaaahhhhhhh – You’re selling a product that is wall powered.
  • YES – You’re selling a product that is an intentional transmitter, or has a lot of fast signals, or is manufactured in large volumes.
  • SMH – You’re the manufacturer of a neon sign that is taking out all wireless signals within a few blocks.

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Parts Bin Bonanza Leads To Arduino FM Radio

December 29, 2016 by 15 Comments

Trolling eBay for parts can be bad for your wallet and your parts bin. Yes, it’s nice to be well stocked, but eventually you get to critical mass and things start to take on a life of their own.

This unconventional Arduino-based FM receiver is the result of one such inventory overflow, and even though it may take the long way around to listening to NPR, [Kevin Darrah]’s build has some great tips in it for other projects. Still in the mess-o-wires phase, the radio is centered around an ATmega328 talking to a TEA5767 FM radio module over I²C. Tuning is accomplished by a 10-turn vernier pot with an analog meter for frequency display. A 15-Watt amp drives a pair of speakers, but [Kevin] ran into some quality control issues with the amp and tuner modules that required a little extra soldering as a workaround. The longish video below offers a complete tutorial on the hardware and software and shows the radio in action.

We like the unconventional UI for this one, but a more traditional tuning method using the same guts is also possible, as this retro-radio refit shows.

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