A loudspeaker with a supercapacitor PCB next to it

Hackaday Prize 2023: Supercapacitors Let Solar Speaker Work In Darkness

July 8, 2023 by Robin Kearey 13 Comments

Solar panels are a great way to generate clean electricity, but require some energy storage mechanism if you also want to use their power at night. This can be a bit tricky for large solar farms that feed into the grid, which require enormous battery banks or pumped storage systems to capture a reasonable amount of energy. It’s much easier for small, handheld solar gadgets, which work just fine with a small rechargeable battery or even a big capacitor. [Jamie Matthews], for instance, built a loudspeaker that runs on solar power but can also work in the dark thanks to two supercapacitors.

The speaker’s 3D-printed case has a 60 x 90 mm² solar panel mounted at the front, which charges a pair of 400 Farad supercaps. Audio input is either through a classic 3.5 mm socket or through the analog audio feature of a USB-C socket. That same USB port can also be used to directly charge the supercaps when no sunlight is available, or to attach a Bluetooth audio receiver, which in that case will be powered by the speaker.

A speaker's passive radiator next to a solar panel — The solar panel sits right next to the passive radiator before both are covered with speaker fabric.

The speaker’s outer shell, the front bezel, and even the passive radiator are 3D-printed and spray-painted. The radiator is made of a center cap that is weighed down by a couple of M4 screws and suspended in a flexible membrane. [Jamie] used glue on all openings to ensure the box remains nearly airtight, which is required for the passive radiator to work properly. Speaker fabric is used to cover the front, including the solar panel – it’s apparently transparent enough to let a few watts of solar power through.

A salvaged three-inch Bose driver is the actual audio source. It’s driven by a TI TPA2013D1 chip, which is a 2.7 W class-D amplifier with an integrated boost converter. This enables the chip to keep a constant output power level across a wide supply voltage range – ideal for supercapacitor operation since supercaps don’t keep a constant voltage like lithium batteries do.

[Jamie] has used the speaker for more than nine months so far and has only had to charge it twice manually. It probably helps that he lives in sunny South Africa, but we’ve seen similar solar audio projects work just fine in places like Denmark. If you’re taking your boombox to the beach, a sunscreen reminder feature might also come in handy.

Raspberry Pi Pico W Now Supports Bluetooth

June 15, 2023 by Tom Nardi 11 Comments

What’s the best kind of upgrade a piece of consumer technology can get? A free one that doesn’t require you to do anything other than accept a new version of the software it’s running.

That’s precisely what every current (and future) owner of the Raspberry Pi Pico W just got with the addition of Bluetooth support to SDK 1.5.1. This is possible because the CYW43439 radio chipset used on the wireless version of the Pi Pico has always had Bluetooth capabilities, they just weren’t officially accessible from the C or MicroPython environments until now. In a corresponding blog post, [Eben Upton] explains that part of the delay was due to difficulties in getting both WiFi and Bluetooth connections to work simultaneously over the three-pin SPI bus that links the two chips on the board.

One thing that struck us as particularly interesting here is the use of BlueKitchen’s BTStack to provide support for both Bluetooth Classic and Low Energy profiles. This library is released under a modified version of the BSD 3-Clause license that otherwise specifically forbids commercial usage. That would be a problem for anyone who wanted to sell a gadget built around the Pico W, so Raspberry Pi Ltd negotiated — and presumably paid for — a special dispensation so commercial use is in the clear.

We should note that technically Bluetooth support was available in a beta state previously, albeit without this new license agreement made with BlueKitchen. Though anyone with a keen eye knew Bluetooth support was coming well before that, our own [Elliot Williams] called it when he first set eyes on the Pi Pico W back in 2022.

Nokia N-Gage QD Becomes Universal Bluetooth Gamepad

May 26, 2023 by Donald Papp 5 Comments

The Nokia N-Gage might not have put up much of a fight against Nintendo’s handheld dynasty, but you can’t say it didn’t have some pretty impressive technology for the time. [BeardoGuy] happens to have a perfectly functional N-Gage QD, which he turned into a universal Bluetooth gamepad.

The handheld runs a program that makes it act as a gamepad, and a DIY Bluetooth dongle is required on the client side. The dongle consists of an ATtiny85-based development board and HC-06 Bluetooth module, and will be recognized as a USB gamepad by just about anything it plugs in to.

[BeardoGuy]’s custom GamepadBT program sends button events via Bluetooth to the dongle, and those events are then sent via USB and look just like those from any standard gamepad.

This project can be used as a resource for how to implement a USB gamepad, whether on a Nokia N-Gage or not. You can see all the details at the project’s GitHub repository, and watch it in action in the video embedded below.

As for the Nokia N-Gage itself, one might be interested to know there’s an up-to-date development environment and even Wordle has been ported to the N-Gage. It may look like a relic of the past, but it is far from being forgotten.

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An orange m5stickc plus strapped to a wrist in the foreground with the persons other hand pressing down on the top of an installed hat, communicating with another m5stickc plus in the background on the table.

M5StickC Turned Wearable Morse Code Trainer

April 20, 2023 by Abe Connelly 8 Comments

Have you ever felt the options for Morse code communication were too limited? Well, look no further than [marsPRE]’s open source WristMorse communicator that can connect over WiFi, can act as a Bluetooth keyboard or just be used as a Morse Code trainer.

[marsPRE] uses the M5StickC Plus as the base device and attaches a custom “hat” consisting of a 2.5 mm plug for a radio connection and two capacitive touch paddles that act as the Morse Code keyer. The add-on is housed in what looks like a custom 3D print and hangs off of the end of the M5StickC Plus, connecting the hat through an eight 0.1 inch pin header.

Using the M5StickC Plus allows [marsPRE] to focus on the software, providing different options for training, communication and even using the device as a Bluetooth keyboard. The two touch sensors allow for a semi automatic keying, with the top sensor used for long dashes and the bottom sensor used for short dashes.

[marsPRE] took inspiration from the Morserino-32 and has made the wrist morse code trainer open source software and available through GitHub for anyone wanting to take a look. Morse code may an old encoding method but it’s one that’s worthy of respect. You never know when you might need to send a message from your dreams or to translate spoken word Morse code.

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A first-generation car phone connected to a piece of prototype board with a BlueTooth module

Custom Bluetooth Adapter Brings 1990s Car Phone Back Online

April 13, 2023 by Robin Kearey 20 Comments

[Jeff Lau]’s Mitsubishi 3000GT comes with all the essential features you’d expect in a fancy sports car from 1993: pop-up headlights, movable spoilers, and a fully-functional telephone handset in the center console. The phone was fully functional until North America’s first-generation AMPS cellular network was shut down back in 2008, since then, it hasn’t done much but show “NO SVC” on the display. That is, until [Jeff] decided to build a Bluetooth adapter that lets it connect to a modern smartphone.

The easy solution would have been to simply connect the handset’s speaker and microphone to a standard Bluetooth headset, but that would have destroyed the 1990s aesthetic it had going on. So what [Jeff] did instead was construct a plug-in module that hooks up to the phone’s base station in the trunk and communicates directly with all the existing systems. That way, the phone works in exactly the same way it always did: the radio is automatically muted during calls, the buttons on the steering column work as expected, and you can even dial and store numbers using the buttons on the handset.

A car phone base station and wiring in the trunk of a Mitsubishi 3000GT — No modifications required: the BlueTooth module is connected using the factory-installed cabling

It took a lot of reverse-engineering to figure out the technical details of the DiamondTel Model 92 that came with the car as a factory option. [Jeff] helpfully documented all of his findings on the project’s GitHub page, making it easy for anyone with a similar system to implement their own upgrades. The main components of the upgrade kit are a BM62 Bluetooth module that connects to a modern phone, a PIC18F27Q43 microcontroller to implement the car phone’s interface and menus, and several analog chips to process the audio. All of these are mounted on a piece of prototype board and housed in a standard plastic enclosure that neatly fits on top of the existing equipment in the trunk.

While the hardware mod is a pretty neat job already, the real strength of this project is in the software. [Jeff] worked hard to implement all relevant features and mimic the original interface as much as possible, even using 1G phone test equipment to simulate incoming calls from the long-gone network. He also added menu features to enable Bluetooth pairing, use voice assistants, and even play games including versions of Snake and Tetris stripped down to match the handset display’s constraints.

As classic phone conversions go, this is definitely one of the most impressive. [Jeff]’s extensive documentation should come in handy if you’ve got a similar model, but if you don’t, there’s still plenty of ways to connect modern electronics without defacing your classic ride’s interior.

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The BLE Datalogging Scale Of A Thousand Uses

March 29, 2023 by Lewin Day 7 Comments

Whether you’re making coffee or beer or complex chemicals, weighing your ingredients carefully and tracking them is key to getting good results. [Tech Dregs] decided to build a logging scale that would work seamlessly with his smartphone, and shared the design on YouTube.

The design begins with a Greater Goods manual electronic scale, which was chosen for its convenient design and 750 gram load cell. Once cracked open, [Tech Dregs] pulled out the original PCB to replace it with his own. Only the original buttons are used, with an Seed Xiao ESP32-C3 replacing the scale’s original brains. The original LCD screen was swapped out for an OLED display, and it also got a rechargeable lithium battery for better usability.

The real value of the project, though, is its communication capability. It’s able to talk to an Android smartphone over Bluetooth Low Energy. Thanks to a custom app, [Tech Dregs] is able to log weight readings from the scale over time and even graph them live on the smartphone. As a demonstration, the scale is used to log the weight of a cup as it fills with a shot of coffee, which should serve [Tech Dregs] well in his coffee automation projects.

We’ve seen bathroom scales hacked before, too, with similar connectivity upgrades.

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Flipper Zero Mayhem Hat Adds Camera, More Radios

March 12, 2023 by Tom Nardi 28 Comments

For a device advertised as the “Multi-tool Device for Hackers”, the Flipper Zero already offers a considerable list of onboard capabilities. But some hard decisions had to be made to get the retail price down, so features like WiFi and Bluetooth had to be left off. Luckily, there’s an expansion interface along the top of the device which makes it possible to plug in additional hardware.

One of those expansions is the “Mayhem Hat” from [Erwin Ried]. This board adds many requested features to the Flipper Zero, as well as some that might not seem as obvious. The addition of an ESP32-CAM brings WiFi and Bluetooth to the party, while also unlocking access to the highly-capable ESP32Marauder firmware and the plethora of security research tools therein.

But the camera also enables some interesting features, such as motion detection and the ability to read QR codes. It even lets you use the Flipper as an impromptu digital camera, complete with an onscreen viewfinder reminiscent of the Game Boy Camera.

What’s more, the Mayhem Hat features its own expansion capabilities. There’s a spot to plug in either a CC1101 or NRF24l01 radio module, both of which are supported by community developed plugins that allow the user to sniff out and hijack signals. There are also extra pins for connecting your own sensors or hardware. In the demo video below you can see the device automatically detect the popular DHT11 environmental sensor and display the current temperature and humidity readings.

[Erwin] has the Mayhem Hat up for sale on Tindie, but as of this writing, is currently out of stock. Apparently, demand for the add-on boards is just as high as for the Flipper Zero itself — not a huge surprise, given the excitement we saw around this platform during its $4.8 million Kickstarter campaign.

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