This Bluetooth GATT Course Is A Must Watch

October 4, 2024 by Arya Voronova 6 Comments

Bluetooth is a backbone technology for innumerable off-the-shelf and hacker devices. You should know how to work with it – in particular, nowadays you will certainly be working at the Bluetooth GATT (Generic Attribute) layer. This two-part project by [V. Hunter Adams] of Cornell fame spares no detail in making sure you learn Bluetooth GATT for all your hacking needs – not only will you find everything you could want to know, you also get example GATT server and client application codebases to use in your projects, designed to work with the commonly available Pi Pico W!

What’s better than a visual demonstration? The video below shows the GATT server running on a Pico W – handling six different parameters at once. [Hunter] pokes at the server’s characteristics with a smartphone app – sending string data back and forth, switching an LED, and even changing parameters of audio or video color output by the Pico. Flash the server code into your Pico W, play with it, read through it, and follow the tutorial to learn what makes it tick.
Continue reading “This Bluetooth GATT Course Is A Must Watch” →

A new display wedged into a car-based fridge

New Brains Save 12 V Fridge From The Scrap Heap

March 14, 2024 by Dave Rowntree 17 Comments

Recently [nibbler]’s Evakool 55L vehicle fridge started to act strangely, reporting crazy temperature errors and had no chance of regulating. The determination was that the NTC thermistor was toast, and rather than trying to extricate and replace this part, it was a lot easier to add a new one at a suitable location

A straight swap would have been boring, so this was a perfect excuse for an overboard hack. Reverse engineering the controller wouldn’t be easy, as the data wasn’t available, as is often the case for many products of this nature.

While doing a brain transplant, the hacker way, we can go overboard and add the basics of an IoT control and monitoring system. To that end, [nibbler] learned as much as possible about the off-the-shelf ZH25G compressor and the associated compressor control board. The aim was to junk the original user interface/control board and replace that with a Raspberry Pi Pico W running CircuitPython.

For the display, they used one of the ubiquitous SH1106 monochrome OLED units that can be had for less than the cost of a McDonald’s cheeseburger at the usual purveyors of cheap Chinese electronics. A brief distraction was trying to use a DS18B20 waterproof thermometer probe, which they discovered didn’t function, so they reverted to tried and trusted tech — a simple NTC thermistor.

Continue reading “New Brains Save 12 V Fridge From The Scrap Heap” →

A red circuit board with four wires running from an IMU to a Pi Pico W. This is all attached to a clear plastic baton.

An Electronic Orchestra Baton

December 31, 2023 by Navarre Bartz No comments

The conductor of an orchestra may look unassuming on the street, but once they step onto their podium, they are all powerful. If you’ve ever wanted to go mad with power in the comfort of your own home, try this electronic orchestra baton by [Larry Lu] and [Kathryn Zhang].

The wireless baton “peripheral” part of the system uses a Pico W and an IMU to detect the speed of conducting a 4/4 measure. That information is then transmitted to the “central” Pico W access point which plays a .wav at the speed corresponding to the conductor’s specified beats per minute (BPM). Setting the baton down will pause the visualizer and audio playback.

The “central” Pico W uses direct memory access (DMA) and SPI communication to control the audio output and VGA visualization. Since most .wav files have a sample rate of 44.1 kHz, this gave the students a reference to increase or decrease the DMA audio channel timer to control the playback.

Want some more musical hacks? Checkout this auto-glockenspiel or how the original iPod was hacked.

Continue reading “An Electronic Orchestra Baton” →

2023 Halloween Hackfest: Haunted Keyboard Is Free From Ghosting

October 20, 2023 by Kristina Panos 1 Comment

This may look like another DIY mechanical keyboard, but it’s hiding a secret. [Mx. Jack Nelson] has combined Halloween and keyboards in glorious, haunted fashion. Type a line, any line into this bad boy and you get a spooky, sort of cryptic response generated by AI.

Essentially, a Raspberry Pi Pico W does all the work, it handles the keyboard matrix, connects to Wi-Fi, sends the input to ChatGPT, and spits the response out on the screen wherever the cursor happens to be. Incidentally, it turns out [Mx. Jack Nelson] used ChatGPT to generate much of the CircuitPython code.

The layout is a custom 40% that is heavily influenced by the Akko 40%, with the Ctrl, Alt, and Win keys replaced by Ctrl, Cmd, and Opt. This was [Mx. Jack Nelson]’s first PCB, and you never forget your first. You don’t want to miss the demo video after the break.

Are keyboards just not spooky enough for you? Here’s a creepy baby doll that does basically the same thing.

Continue reading “2023 Halloween Hackfest: Haunted Keyboard Is Free From Ghosting” →

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.

This WiFi Signal Strength Meter Ain’t Afraid Of No Ghosts

December 23, 2022 by Dan Maloney 5 Comments

The original Ghostbusters movie is a classic that’s still delivering nearly 40 years after its release — just let that sink in for a minute. Almost every aspect of the film, from hand props to quotes, is instantly recognizable, even to people who haven’t based their lives on the teachings of [Venkman], [Stantz], and [Spengler]. To wit, we present this PKE meter-style WiFi scanner.

Of course, [Kevin McAleer]’s project is strictly in the “Just for Fun” category. But that doesn’t mean it’s not at least somewhat useful. The design is pretty close to the original PKE meter, with a little bit of creative license taken to make it easier to build. Guts include a Raspberry Pi Pico W and a generous 320×240 LCD display. The body of the meter is entirely 3D printed; design files are of course available. The meter’s arms are geared together to move with a single hobby servo.

On the software side, [Kevin]’s GUI lets users see a list of WiFi hotspots in the area and select one from the list. From there, the position of the arms is determined by the RSSI for the hotspot, similar to how the prop was supposed to indicate the proximity to a spook, specter, or ghost. There’s perhaps a bit of a missed opportunity by not adding LEDs to the arms, but we’ll let that slide.

The video below has full design and build details, but fair warning that it’s a bit on the long side. That’s probably just a reflection of how much work [Kevin] put into this, though. Of course, you may rather build a PKE meter that “actually” detects ghosts, in which case we’ve got you covered.

Continue reading “This WiFi Signal Strength Meter Ain’t Afraid Of No Ghosts” →