Radio-Gaga Is A Toddler Friendly Remote In A Radio

July 9, 2026 by 2 Comments

Humans of all ages like music, but you can’t exactly pass a toddler the aux cable. That’s not to say the younger set don’t have their own particular tastes– they absolutely do, and they absolutely love to take control and inflict them on the rest of us. [nbr23] has a toddler who loves both music and tactile controls, and decided to combine the two for them with a project he calls Radio-Gaga, which is a gutted Panasonic radio that calls up tunes via Home Assistant.

Interestingly enough the radio is now just a remote control– the speaker has been removed along with the rest of the radio hardware. The buttons and dials are still there, though, letting the toddler control what tunes are on offer and at what volume via couple of potentiometers hooked to an ESP32. The sound itself is being served up from the homelab to a USB speaker. There’s one notable flaw with this architecture: if the batteries die on the remote, “Let it Go” does not until an adult intervenes manually or recharges the remote.

One interesting lesson [nbr23] wanted to share was that he was able to improve an unsatisfactorily slow startup time by assigning the device a static IP on his network– apparently the single longest step in getting the tunes going was negotiating a DHCP lease. Skipping that gets the tunes playing in under a second, which is fast enough even for the most impatient of tiny humans.

If you prefer a more self-contained device, we’ve seen toddler jukeboxes that keep storage and speaker built-in, many with NFC control. 

DIY SI5351 Radio Tunes In SW, MW, And More

July 2, 2026 by 12 Comments

There are plenty of radios you can buy that pick up MW and SW bands if that’s what you’re into. Or, you can follow [mircemk]’s example, and whip one up yourself instead.

The build employs an ESP32 as the brains of the operation. It’s hooked up to a rotary encoder and a small colour TFT screen, which displays an old-school style tuning dial for choosing the desired frequency. This setup is paired with an Si5351—a capable clock generator chip that can deliver just about any frequency from <8KHz up to 150+ MHz on command. There’s naturally a bunch of supporting analog hardware for the radio end of things, plus a NE612 mixer IC and a PAM8403 class D audio amplifier board, hooked up to a small 0.25W speaker for audio output. [mircemk] has set up the rig to act as a simple radio set, or, with the flick of a switch, it can be configured for SDR use with an attached computer.

It’s a handsome build, and one that likely proves a pleasant way to browse the MW and SW bands on a rainy afternoon. We’ve looked at other hardware in this category before, too. Video after the break.

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A drone is shown flying above some trees and a building. A pink cloud of dots appears above the drone, and a purple cloud below the drone. Grey crosshairs are to the right of the drone.

Seeing The World In Radio Waves With The QuadRF

June 20, 2026 by 37 Comments

Although the basic principle of radio direction finding is easy to understand (measure the phase difference between different antennas, then calculate the angle of arrival from this difference), the radio hardware to actually implement this has historically been hard for hackers to access. The QuadRF project aims to change this by building a phase-coherent four-channel SDR which makes direction mapping easy (GitHub repository).

The QuadRF uses two boards: one to receive and pre-process radio waves, and a Raspberry Pi 5 for additional processing. The RF board has four patch antennas, each capable of either transmitting or receiving in the 4.9 GHz to 6.0 GHz range, with switchable right- or left-hand polarization. For on-device processing, it uses a Lattice ECP5 FPGA, which uses two MIPI cables to connect to the camera and display interfaces on the Raspberry Pi. These form a very high-speed data exchange, and after further processing, the Pi can pass data on over Ethernet or Wi-Fi. Individual QuadRF boards can connect together in a lattice grid to form larger phased arrays.

The QuadRF’s software shows off its real strength: it’s compatible with standard programs like GNU Radio, but it also hosts a few of its own programs. The most striking of these is an “RF camera” which scans its entire frequency range at 30 fps, tracking the direction of detected signals and visualizing them on a spatial plot. When overlaid on a camera feed, this plot lets one easily see the radio signals emitted from electronics; as an example, the creators tracked a drone in flight, even distinguishing the two radio transmitters on the drone.

This isn’t the first multi-antenna SDR we’ve seen, though this is the first that could transmit. It’s important to be careful, though: some applications of this kind of hardware run afoul of arms regulations.

Thanks to [Swake] for the tip!

A Peek Inside The Secret Lagercrantz Suitcase Radio

June 12, 2026 by 7 Comments

What counts as portable is somewhat a matter of opinion, especially over the years. [Helge Fykse] has a portable spy radio of Swedish origin. For its time, it was considered very portable, crammed into a good-sized suitcase.

You can see the large crystal that sets the transmit frequency and a key to send Morse code. The receiver has a VFO, so it was more agile. Based on the regenerative knob, it appears the receiver was of the regenerative type. The suitcase had its own battery, and with tubes, it could probably put out some kind of signal if connected to anything metal, like bedsprings, a clothesline, or anything. There was a lightbulb to let you see when you were transmitting maximum power.

Speaking of tubes, there were five inside, two for the transmitter and three for the receiver. The radio had storage for spare tubes, and the agent could maintain the radio in the field.

You not only get a peek inside the suitcase, but a look at the schematic. The radio is a model of simplicity, but we are certain it did its job.

We love looking at exotic spy gear, especially radios.

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Custom FM Radio Station Powered By Shell Scripts

June 9, 2026 by 21 Comments

[Trwmato] wanted to spend more time listening to a normal radio to cut back on phone use. But the programming wasn’t quite right so, of course, the solution was to spin up a custom radio station!

The station in question uses a Pi Zero to poll podcasts and news from RSS feeds and automatically mixes them with local content and sends it out via Bluetooth. An FM transmitter allows it to still work on the FM radio, too. Grabbing podcasts isn’t very difficult, thanks to podget. The real logic is in how long to retain things and creating a playlist that both prioritizes fresh content while not repeating things too often. Did we forget to mention the whole thing is a collection of shell scripts?

We could see this as the start of a cool project to have a “radio station” for a school, organization, or company. It is easy to understand and modify.

We often argue that the much-maligned bash script is sometimes the right tool for the job. You can even do things like critical sections in them.

Web-Based Control For A CB Radio

June 3, 2026 by 20 Comments

There was a time when a CB radio was a simple affair: a small box with a channel selector, volume, and squelch controls. No longer it seems, because they can now be multi-mode devices that equal the capabilities of amateur radio rigs if not surpass them. [ThatCrazyDcGuy] has one, an Albrecht AE-5900, which has the interesting feature that it can be entirely controlled from its microphone. This led to a web-based interface for the rig, through clever emulation of the microphone.

The communication between rig and microphone is a serial line, for which an FT232 USB-to-serial interface is pressed into service. A USB sound card handles the audio along with some little transformers for isolation, and a USB hub joins everything together. The whole is mounted on perfboard in a small enclosure, and plugged into a Raspberry Pi which acts as a server. This is running a Python script that expose a web front end to control the rig. We like the way this has been done, with minimal intrusion into the radio itself.

Far less so than this CB to 6 meter conversion we featured a while back.

Spy Tech: A Quiet Radio For Spies

May 20, 2026 by 9 Comments

Normally, when you think of a radio transmitter, you want the strongest signal and range. But if your radio operator is secretly operating as a spy, broadcasting their position isn’t a feature; it is a liability. This fact didn’t escape World War II radio designers.

In late 1942, the British realized they needed a way for Special Operation Executive agents, resistance members, and other friendly forces to communicate with an aircraft without attracting undue attention. Two engineers from the Royal Corps of Signals developed a pair of transceivers — the S-Phone — operating around 380 MHz just for this purpose. Frequencies this high were unusual at the time, which further deterred enemy detection.

The output power was below 200 mW, and the ground equipment consisted of a dipole strapped to the operator. No transistors, so with rechargable batteries, the rig weighed about fifteen pounds and reused some parts of a paratrooper radio, Wireless Set Number 37. The other side of the connection was installed in an airplane.

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