Radiochat Is A Simple LoRa Interface Over WiFi

LoRa is often talked about as a potentially useful solution for emergency communication. The problem is, few of us are running around with LoRa hardware on a day-to-day basis. Student [William Barkoff] designed the Radiochat device as a simple tool that could pair with virtually anything over WiFi, and allow it to send and receive LoRa messages.

Radiochat is based on the Raspberry Pi Pico W, and uses the microcontroller’s wireless hardware to communicate with other devices. It provides a WiFi network that devices like laptops or smartphones can connect to. The Pico serves up a simple web page which accepts text input. Type in a message and hitting enter and the Pico will command a LoRa radio module over SPI to send that message out over the airwaves. It can then be picked up by another Radiochat module which displays the message on its own webpage.

It’s in an early state of development, and the demo video shows there are still some bugs to work out. Ultimately, though, it could be a cheap battery-powered device that lets smartphones and laptops chat over LoRa in remote areas. Indeed, [William’s] trips to New Mexico on model rocketry expeditions were a big inspiration for the project.

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Raspberry Pi Pico Becomes MIDI-Compatible Synth

ECE 4760 is a microcontroller course that runs at Cornell every year, and it gives students a wide remit to pursue various kinds of microcontroller projects. [Pelham Bergesen] took the class and built himself a MIDI-controllable synthesizer out of a Raspberry Pi Pico.

[Pelham] coded a library to parse MIDI messages on the Pico, with the microcontroller’s UART charged with receiving the input data. MIDI is basically just serial at a baud rate of 31.25k, with a set message structure, after all. From there, the Pico takes the note data and plays the relevant frequencies by synthesizing square waves using a PWM output. A second PWM channel can also be blended with the first to generate more complex tones.  The synthesizer is designed to be used with a source of MIDI note data such as a keyboard controller; [Pelham] demonstrates the project in use with a Roland JD-XI. It’s a fairly basic synthesizer, but [Pelham] does a good job of explaining all the steps required to get this far. If you’ve never done an audio or MIDI project before, you might find his guide very helpful for the way it steps through the basics.

[Pelham] didn’t get to implement fancier features like direct digital synthesis (DDS) or analog audio effects before the class closed out. However, that would be an excellent project for anyone else developing their own Pico synthesizer. If you whip up something that sounds good, or even just interesting, be sure to notify us on the tipsline. Video after the break.

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Pico Makes A So-So Keyboard Neat-O

When someone gives you a crappy little toy keyboard, what can you do? Sadly plunk on the thing one note at a time? Well yes, but that’s not going to get you on Hackaday. Do what [Turi] did and give that thing a complete overhaul.

[Turi] threw away the original controller board, keeping only the keys, buttons, case, speaker, and a little bit of the original powder yellow enclosure. The Picophonica’s new brain is, you guessed it, a Raspberry Pi Pico. This enables [Turi] to use [Ryo Ishigaki]’s pico_synth_ex synthesizer and introduce MIDI out via USB-C.

The new engine does things that little keyboard could never have dreamed of originally, especially considering it wasn’t even polyphonic. Those fourteen white buttons now control things like sustain, cutoff, LFO rate, decay, and so on. Now it sounds great!

Be sure to check out the brief build video after the break. Excluding drums, the soundtrack was made entirely on the Picophonica.

Of course, Picos aren’t just good for musical keyboards. Use one to convert an old proprietary keyboard to PS/2, or create your own.

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Metronome Flashes And Vibrates To The Beat

Annoying though they can be, if you play any kind of instrument, you will definitely benefit from using a metronome. While many of them thock or otherwise tock, the VRRVRR metronome from [Turi] works a little differently.

In addition to flashing LEDs, the VRRVRR contains a small vibrating motor. If you’re wondering about the name, it comes from the fact that it vibrates and makes a sort of vrr vrr sound. Need to be quiet? A small switch on the side shuts off the vibrations.

The 4×4 keypad really allowed [Turi] to cram in a bunch of features using both short and long press to do different things. On short press, the digits set the tempo. When not typing in a tempo, zero can be used to enter a tempo by tapping. The letters load preset tempos, and the +/- keys increase and decrease it.

Inside the basswood enclosure is a Raspberry Pi Pico, the vibration motor, and various other bits and bobs that make it go. There’s even an LED to indicate that it’s time to charge the lithium battery. If you want to build your own, head on over to GitHub, but be sure to take the brief VRRVRR tour after the break.

We don’t see too many metronomes around here, but we do have this nice teardown to offer you.

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Arbitrary Wave Generator For The Raspberry Pi Pico

Once upon a time, if you wanted to generate some waveforms, you needed to buy an expensive off-the-shelf function generator or whip up a big pile of analog electronics. Not so today, when you can grab a fast microcontroller off the shelf and have it squirt out whatever fancy waves you might desire. That’s just what [rgco] did to build this nifty arbitrary wave generator.

The build improves on prior work by [rgco] with the Arduino Uno, with which they built a device that could output at 381 kilosamples per second, with each sample update taking 42 instruction cycles. Thanks to the Pi Pico’s faster clock speed and certain performance optimizations, they were able to up that to a mighty 125 megasamples per second, using the DMA and PIO subsystems to output a new sample every single clock cycle.

The result is a cheap function generator you can build with a Pi Pico and a handful of resistors, which will probably cost you the grand total of $12. It readily outperforms, at least in regards of speed, devices based on the AD9833 function generator chip, which only runs at 25 megasamples. Plus, that chip can only output sines, triangles, and squares!

Even a passable function generator can be a useful tool to have in the workshop, as we’ve seen before. Video after the break.

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Simple Badge Is Simple, But It’s Yours

Making conference badges, official or unofficial, has become an art form. It can get pretty serious. #badgelife.

But DEFCON-goers aren’t the only people making fancy personalized nametags. Hams often had callsign badges going back as far as I can remember. Most were made of engraved plastic, but, at some point, it became common to put something like a flashing LED on the top of the engraved antenna tower or maybe something blinking Morse code.

Going back to that simpler time, I wanted to see if I could make my own badge out of easily accessible modules. How easy can it be? Let’s find out. Along the way, we’ll talk about multicore programming, critical sections, namespaces, and jamming images into C++ code. I’ll also show you how to hijack the C preprocessor to create a little scripting language to make the badge easier to configure.

Bottom Line Up Front

The photo shows the Pico badge. It has an RP2040 CPU but not a proper Raspberry Pi Pico. The Waveshare RP2040-Plus clone has a battery connector and charger. It also has a reset button, and this one has 16 MB of flash, but you don’t need that much. The LCD is also a Waveshare product. (This just happened to work out. I bought all of this stuff, and I don’t even know anyone at Waveshare.) The only other thing you need is a USB C cable and a battery with an MX 1.25 connector on it with the correct polarity. Hardware done! Time for software.

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KaboomBox Is A Firecracker Of A Music Player

Ka-chunk. Let’s face it, 8-tracks were not that great. But the players, that’s another story. The Panasonic RQ-830S, aka the dynamite or TNT player is just one of many lovely designs that used to grace the shelves of electronics stores. Hackaday alum [Cameron Coward] came across a non-working model and used it to create the KaboomBox.

Just like before, all [Cameron] has to do is stick a tape in, and music starts playing. But now, instead of using rust on tape, the music is accessed via RFID and lives on an SD card inside the 8-track player.

Power it on, and a tiny LCD screen showing through the track number window first displays the KaboomBox logo, then shows a timer whenever it’s waiting for a tape. And just like before, pushing down on the plunger skips to the next track.

The new guts include a Raspberry Pi Pico and an RFID reader, plus a DF Player Mini to handle the digital-to-analog conversion and amplify the signal, and an SD card to store the music. Now, [Cameron] is only limited by the size of the SD card. Check out the demo video after the break.

We’ve seen all kinds of boomboxen around here, from the lit to the Bluetooth to the payphone variety.

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