Wireless Hacks

1097 Articles

This Bluetooth GATT Course Is A Must Watch

October 4, 2024 by 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.
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A 1930s Ham Station

September 14, 2024 by 11 Comments

[Mikrowave1] wanted to build an authentic 1930s-style ham radio station that was portable. He’s already done a regenerative receiver, but now he’s starting on a tube transmitter that runs on batteries. He’s settled on a popular design for the time, a Jones push-pull transmitter. Despite the tubes, it will only put out a few watts, which is probably good for the batteries which, at the time, wouldn’t have been like modern batteries. You can see the kickoff video below.

According to the video, these kinds of radios were popular with expeditions to exotic parts of the world. He takes a nostalgic look back at some of the radios and antennas used in some of those expeditions.

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Wardriving Tools In The Modern Era

August 22, 2024 by 13 Comments

When WiFi first came out, it was a super exciting time. The technology was new, and quite a bit less secure back then—particularly if not configured properly. That gave rise to the practice of wardriving—driving around with a computer, looking for unsecured networks, often just for the fun of it. [Simon] has been examining this classic practice from a modern perspective. 

He’s been at the game for a long time—from back in the days when you might head out with a thick old laptop, a bunch of PCMCIA cards, and dangly antennas. It’s much more advanced these days, given we’ve got WiFi on all different bands and Bluetooth devices to consider to boot. Heck, even Zigbee, if you’re hunting down a rogue house full of Internet of Things gadgets.

Today, when he’s out researching the wireless landscape, he uses devices like the Flipper Zero, the Raspberry Pi, and a Google Pixel 5 running the WiGLE WiFi Wardriving app. [Simon] notes that the latter is the easiest way to get started if you’ve got an Android phone. Beyond that, there’s software and hardware out there these days that can do amazing things compared to the simple rigs of yesteryear.

If you’re out looking for free internet these days, wardriving might be a bit pointless given it’s available in practically every public building you visit. But if you’re a wireless security researcher, or just curious about what your own home setup is putting out, it might be worth looking at these tools! Happy hunting.

Australia Didn’t Invent WiFi, Despite What You’ve Heard

August 20, 2024 by 61 Comments

Wireless networking is all-pervasive in our modern lives. Wi-Fi technology lives in our smartphones, our laptops, and even our watches. Internet is available to be plucked out of the air in virtually every home across the country. Wi-Fi has been one of the grand computing revolutions of the past few decades.

It might surprise you to know that Australia proudly claims the invention of Wi-Fi as its own. It had good reason to, as well— given the money that would surely be due to the creators of the technology. However, dig deeper, and you’ll find things are altogether more complex.

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Decoding Meshtastic With GNU Radio

June 26, 2024 by 21 Comments

Meshtastic is a way to build mesh networks using LoRa that is independent of cell towers, hot spots or traditional repeaters. It stands to reason that with an SDR and GNU Radio, you could send and receive Meshtastic messages. That’s exactly what [Josh Conway] built, and you can see a video about the project, Meshtastic_SDR, below. The video is from [cemaxecuter], who puts the library through its paces.

For hardware, the video uses a Canary I as well as the WarDragon software-defined radio kit which is an Airspy R2 and a mini PC running Dragon OS — a Linux distribution aimed at SDR work —  in a rugged case. GNU Radio, of course, uses flows which are really just Python modules strung together with a GUI.

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Screenshot of the blog post, showing how you can optimize your battery level measurement resistor dividers, among many other things

Making Your Wireless Keyboard Truly Low-Power

June 26, 2024 by 46 Comments

The basics of keyboard design are tried and true at this point, but there are still a few aspects yet unconquered. One of them is making your keyboards wireless. You might think it’s easy, but if you just slap a wireless-enabled microcontroller onto your board, you’ll soon be left with a dead battery. Rejoice – [Pete Johanson], creator of ZMK, tells all that you want to know about making your keyboard low-power.

In a lengthy blog post, he goes through everything that a typical keyboard consists of, and points out factor after factor that you never knew could cause a spike in power consumption. Are you using muxes or config options that will force your MCU to always stay alert? Is your voltage regulator’s quiescent current low enough, and can the same be said about other parts you’re using? Does your MCU have to work extra hard transmitting bytes because you’ve put a copper fill under its antenna? Most importantly, is the firmware you’re using designed to optimize power consumption at its core?

If you’ve ever thought about designing low-power keyboards, hell, any low-power device, you seriously should read this post – it will set you at ease by giving you a checklist of things to do, and it also links to quite a few other useful resources, like the ZMK power profiler. Perhaps, if you’re building a wireless keyboard or just creating battery-powered device, you should consider ZMK, as it sure seems to be written with energy efficiency in mind.

Want to learn more about what it takes to build a low-power device? Our 2023 Low-Power Contest attracted a wide range of entrants, and they’ve shared a flurry of methods and tricks you can use to build any sort of battery-juice-sipping gadget.

Showing a Raspberry Pi 4 board connected to an ESP32 devboard using jumper wires for the purposes of this project

ESP-Hosted Turns ESP32 Into Linux WiFi/BT Adapter

June 25, 2024 by 25 Comments

While we are used to USB WiFi adapters, embedded devices typically use SDIO WiFi cards, and for good reasons – they’re way more low-power, don’t take up a USB port, don’t require a power-sipping USB hub, and the SDIO interface is widely available. However, SDIO cards and modules tend to be obscure and proprietary beyond reason. Enter ESP-Hosted – Espressif’s firmware and driver combination for ESP32 (press release)(GitHub), making your ESP32 into a WiFi module for either your Linux computer (ESP-Hosted-NG) or MCU (ESP-Hosted-FG). In particular, ESP-Hosted-NG his turns your SPI- or SDIO-connected ESP32 (including -S2/S3/C2/C3/C6 into a WiFi card, quite speedy and natively supported by the Linux network stack, as opposed to something like an AT command mode.

We’ve seen this done with ESP8266 before – repurposing an ESP8089 driver from sources found online, making an ESP8266 into a $2 WiFi adapter for something like a Pi. The ESP-Hosted project is Espressif-supported, and it works on the entire ESP32 lineup, through an SDIO or even SPI interface! It supports 802.11b/g/n and even Bluetooth, up to BLE5, either over an extra UART channel or the same SDIO/SPI channel; you can even get BT audio over I2S. If you have an SPI/SDIO port free and an ESP32 module handy, this might just be the perfect WiFi card for your Linux project!

There are some limitations – for instance, you can’t do AP mode in the NG (Linux-compatible) version. Also, part of the firmware has blobs in it, but a lot of the firmware and all of the driver are modifiable in case you need your ESP32 to do even more than Espressif has coded in – this is not fully open-source firmware, but it’s definitely way more than the Broadcom’s proprietary onboard Raspberry Pi WiFi chip. There’s plenty of documentation, and even some fun features like raw transport layer access. Also, of note is that this project supports ESP32-C6, which means you can equip your project with a RISC-V-based WiFi adapter.

Title image from [zhichunlee].