Wireless Hacks

1047 Articles

Track Wi-Fi Devices In Your Home

December 25, 2016 by 31 Comments

How do you audit your home Wi-Fi network? Perhaps you log into your router and have a look at the connected devices. Sometimes you’ll find an unexpected guest, but a bit of detective work will usually lead you to the younger nephew’s game console or that forgotten ESP8266 on your bench.

Wouldn’t it be useful if your router could tell you where all the devices connected to it are? If you are [Zack Scholl], you can do all this and more, for his FIND-LF system logs Wi-Fi probe requests from all Wi-Fi devices within its range even if they are not connected, and triangulates their position from their relative signal strengths across several sniffing receivers. These receivers are a network of Raspberry Pis with their own FIND-LF server, and any probe requests they pick up are forwarded to [Zack]’s FIND server (another of his projects) which does the work of collating the locations of devices.

It’s an impressive piece of work, though with a Raspberry Pi at each receiver it could get a little pricey. [Zack] has done other work in this field aside from the two projects mentioned here, his other work includes an implementation of the [Harry Potter] Marauder’s Map.

This is by no means the only indoor location system we’ve seen over the years. One that uses ESP8266 modules for example, or this commercial product that is similar to the project shown here.

These Ornaments Measure Christmas Cheer

December 24, 2016 by 9 Comments

The ornament projects we post around here tend to be simple, stand-alone projects. We are, however, well into the era of the Internet of Things (like it or not) and holiday ornaments need not be single, unconnected blinking objects. For Christmas this year, [Sean Hodgins]  came up with some connected DIY ornaments that respond to Christmas cheer.

[Sean Hodgins] had some beautiful PCBs done up in festive shapes and he hand-pastes and oven-solders the SMD components on both sides. Each one is battery powered and controlled by an ESP8266. LEDs and a button on the front of each ornament comprise the user interface. When the button is pressed, data is sent to a Phant server and a “Christmas Cheer” counter is incremented. Other ornaments, so long as they can connect to the Phant server, will periodically check the counter. If the Christmas Cheer has increased, the ornaments will play a tune and flash some lights.

The ornaments are open-source — [Sean Hodgins] posted the code and PCB designs on GitHub. They look great, and would be a good way to let people know you’re thinking of them over the holidays. Check out this light-up menorah or these lighted acrylic ornaments for more holiday fun!

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Interactive ESP8266 Development With PunyForth

December 23, 2016 by 17 Comments

Forth is one of those interesting languages that has a cult-like following. If you’ve never looked into it, its strength is that it is dead simple to put on most CPUs, yet it is very powerful and productive. There are two main principles that make this possible. First, parsing is easy because any sequence of non-space characters makes up a legitimate Forth word. So while words like “double” and “solve” are legal Forth words, so is “#$#” if that’s what you want to define.

The other thing that makes Forth both simple and powerful is that it is stack-based. If you are used to a slide rule or an HP calculator, it is very natural to think of “5+2*3” as “5 2 3 * +” but it is also very simple for the computer to interpret.

[Zeroflag] created PunyForth–a Forth-like language for the ESP8266. You can also run PunyForth for cross development purposes on Linux (including the Raspberry Pi). The system isn’t quite proper Forth, but it is close enough that if you know Forth, you’ll have no trouble.

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Password-Free Guest WiFi From Raspberry Pi

December 19, 2016 by 31 Comments

Anytime you’re having more than a handful of people over to your place for a wild rager or LAN party (or both), you’ll generally need a way to make sure everyone can get their devices on the network. Normally, this would involve either putting your WiFi password into more phones than you can count or yelling your password across a crowded room. Neither of these options suited [NicoHood] and his partner, however, so he came up with another more secure solution to the WiFi-in-a-crowded-room problem.

He calls his project “guestwlan” and it’s set up to run on a Raspberry Pi with a touch screen. When a potential WiFi user approaches the Pi and requests access to the network, the Pi displays a QR code. Within that code is all of the information that the prospective device needs to connect to the network. For those who have already spotted the new security vulnerability that this creates, [NicoHood] has his guest WiFi on a separate local network just to make sure that even if someone nefarious can access the Internet, it would be more difficult for them to do anything damaging to his local network. As it stands, though, it’s a lot more secure than some other WiFi networks we’ve seen.

[NicoHood] also released his software on Git but it has been configured for use with Arch. He says that it would probably work in a Debian environment (which the Raspberry Pi-specific OS is based on) but this is currently untested. Feel free to give it a try and let us know how it goes.

PIC Mesh, Accessible Distributed Networking

December 17, 2016 by 6 Comments

Wireless networks have been reduced to a component, for most of us. We fit a device, maybe an ESP8266 module or similar, and as if by magic a network exists. The underlying technology has been abstracted into the firmware of the device, and we never encounter it directly. This is no bad thing, because using wireless communication without having to worry about its mechanics gives us the freedom to get on with the rest of our work.

It is however interesting once in a while to take a look at the operation of a real wireless network, and [Alex Wong], [Brian Clark], and [Raghava Kumar] have given us a project with the opportunity to do just that. Their PIC Mesh university project is a distributed wireless mesh network using 2.4GHz NRF24L01 transceiver modules and PIC32 microcontrollers. They have it configured for demonstration purposes with a home automation system at the application layer, however it could be applied to many other applications.

The real value in this project is in its comprehensive but easy to read write-up of the kind you’d expect from a university project. The front page linked above has an overview of how the mesh works, but there are also pages taking us through the hardware, the networking software layer, and the home automation application layer. If you have ever wanted to understand a simple mesh networking system, this is a good place to start.

We’ve covered quite a few mesh networks over the years, but sadly we can only link you to a few of them. We’ve had a mesh network using the Raspberry Pi, Project Byzantium’s “ad-hoc wireless mesh networking for the zombie apocalypse“, and a 1000-node Xbee network for testing purposes.

Bluetooth Turns 5

December 12, 2016 by 23 Comments

Last week, the latest and greatest member of the Bluetooth family of wireless specifications was announced to the world: Bluetooth 5! What main changes are in store? Read the FAQ (PDF), or dig into the full spec (bigger PDF) at 2,800 pages.

Their big-print selling points include “up to 4x the range, 2x the speed, and 8x the broadcasting message capacity” to power the Internet of Things. Etcetera. [Akiba] pointed out via Twitter that they get the fourfold increase in range by adding an extra zero to the “Maximum Output Power” spec, going from 10 mW maximum power to 100 mW. That would do it.

In less snarky news, they’re also allowing for a lower-bitrate mode that will also increase range without simply boosting the power. The spec is actually being changed to let the user work out their optimal blend of power, range, and bitrate. We’re down with that. But you’re not getting 4x the range and 2x the speed without paying the bandwidth piper. That’s just physics.

If you use the beacon mode in Bluetooth Low Energy (BLE), you’ll be happy to hear that they’re lengthening the beacon packet from 31 bytes to 255, so you can send a bunch more data without consuming too much power. That’s the “8x”. Bluetooth 5.0 is also backwards compatible with Bluetooth 4.2, so you don’t have to redo anything if you don’t want to take advantage of the newer features. Your current BLE beacons will keep working.

Finally, there’s some contention-detection and other bandwidth optimizing going on, which is welcome in our crowded 2.4 GHz office spectrum. Our guess is that’s where the “2x speed” is largely coming from, but there are about 2,750 pages that we haven’t read yet, so if you’re digging into the spec, let us know what you find in the comments.

Thanks to [Akiba] for tipping us off to this via Twitter. Go check out his great talk on getting hacker stuff in Shenzhen that was presented at the SuperCon.

Mexican Highschoolers Launch 30 High Altitude Balloons

December 5, 2016 by 15 Comments

No matter whether you call them “picosatellites” or “high altitude balloons” or “spaceblimps”, launching your own electronics package into the air, collecting some high-altitude photos and data, and then picking the thing back up is a lot of fun. It’s also educational and inspirational. We’re guessing that 264 students from 30 high schools in Aguascalientes Mexico have new background screens on their laptops today thanks to the CatSat program (translated here by robots, and there’s also a video to check out below).

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