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.
How would you like to have a WiFi connection that covers 10 miles? Or how about an even wider network made up of a mesh of multiple nodes? It is possible, but there is a catch: you probably need a ham radio license to do it (at least, you do in the United States).
What makes it possible is the realization that conventional WiFi channels 1-6 are inside an existing US ham band. That means (if you are a ham) you can elect to use FCC part 97 rules instead of part 15 that governs WiFi routers. That means you can use more power and–even more importantly–better antennas to get greater range.
Traditionally, hams have used custom firmware for Netgear routers or Ubiquiti hardware. However, [WZ0W] recently posted his experience using Raspberry Pi boards as mesh nodes. The code (which also works with some other single board computers) is available on GitHub (with details on the project blog). [WZ0W] points out that, unlike using a consumer router, using a Pi provides a reasonably powerful computer for hosting services as well as hosting the network.
Continue reading “Ten Mile Raspberry Pi WiFi (with a Catch)”
Off-grid living isn’t for everyone, but it has gotten easier in recent years. Cheap solar panels and wind turbines let you generate your own power, and there are plenty of strategies to deal with fuel, water and sanitation. But the one thing many folks find hard to do without – high-speed internet access – has few options for the really remote homestead. [tlankford01] wants to fix that and is working on an open-source mesh network to provide high-speed internet access to off-grid communities.
But first he had to deal with a major problem. With high-speed access provided by a Clearwire wireless network, streaming content to his two flat-screen TVs wasn’t a problem. At least until Sprint bought Clearwire and shut down the service in early November. Another ISP covered his area, but his house lies in a depression out of line of sight of their tower. So he rigged up a bridge between the WiMAX network and his lab. The bridge sits on a hill in sight of the ISP’s tower 3.5 miles away. Solar panels, a charge controller and deep-cycle batteries power everything, and a wireless link down the hill rounds out the build.
This is obviously a temporary solution, and probably wouldn’t last long in winter weather. But it’s working for now, and more importantly it’s acting as proof of concept for a larger mesh system [tlankford01] has in mind. There are plenty of details on what that would look like on his project page (linked above), and it’s worth a look too if you’re interested in off-grid connectivity.
The world has a bee problem. Honey bees are a major pollinator for all sorts of tasty crops, but an estimated one-third of all colonies in the US have vanished since 2006. These mass disappearances are collectively known as Colony Collapse Disorder, and everything from pesticides to global warming to a new bee virus has been blamed for bees going MIA. Regardless of the cause, keeping the bees that do remain alive and pollinating is important work, and an intelligent bee hive could go a long way toward that goal.
Normally, bee hives are a black – err, white – box, where the bees go about their business without revealing much about it. While bees are amazing animals with an incredibly rich social structure that allows them to, for instance, team together to ventilate a too-warm hive with their wings, or gang up on invading predators, they have their limits, and knowing what’s going on in the hive helps the beekeeper to maintain an optimal environment. [Miguel’s] system, which appears to still be in the prototyping phase, aims to provide the beekeeper with data on temperature and humidity within each hive. GPS tagging allows the beekeeper to track where a hive is, which is important since hives are moved around as various crops begin to flower. The system can even keep track of the comings and goings of bees using photoelectric sensors; while [Miguel] doesn’t go into detail, we imagine that aspect working something like this bee counter we featured a few years back. And being from Portugal, [Miguel] has incorporated cork into the design of the hive, a sustainable material available locally and offering great thermal properties.
Sounds like [Miguel] is onto something here. The bees need all the help they can get, and anything that improves their husbandry will go a long way toward keeping the world fed. We’ll be watching to see where [Miguel] takes this system.
Let’s be honest. Paying electricity bills sucks. The amount paid is always too much, and the temperatures in the building are rarely set at a comfortable level. But now, with the help of this DIY Climate Control system, power-users can finally rejoice knowing that the heating and cooling process of their home (or commercial space) can be easily controlled through the utilization of an XBee Remote Kit and a process called zoning.
The team behind the project is [Doug], [Benjamin] and [Lucas]. They hope to solve the inconsistent temperature problems, which are caused by a moving sun, by open-sourcing their work into the community.
Their XBee system runs on a mesh network making it a perfect tool for sensing and communicating which areas in the house are too hot or too cold. Once the data is collected, XBee modules route the information wirelessly to each other until it reaches a central Arduino gatekeeper; which then decides if it wants to heat, ventilate, or air condition the room.
Not to mention all the added benefits posted below:
Continue reading “THP Entry: Cut Energy Consumption by 30 percent with this WiFi XBee Setup”
With the lessons learned from the Egyptian, Libyan, and Syrian revolutions, a few hardware and software hackers over at Lulzlabs have taken it upon themselves to create a free-as-in-beer and free-as-in-speech digital communications protocol that doesn’t deal with expensive, highly-surveilled commercial and government controlled infrastructure. They call it Airchat, and it’s an impressive piece of work if you don’t care about silly things like ‘laws’.
Before going any further, we have to say yes, this does use amateur radio bands, and yes, they’re using (optional) encryption, and no, the team behind Airchat isn’t complying with all FCC and other amateur radio rules and regulations. Officially, we have to say the FCC (and similar agencies in other countries) have been granted the power – by the people – to regulate the radio spectrum, and you really shouldn’t disobey them. Notice the phrasing in that last sentence, and draw your own philosophical conclusions.
Airchat uses an off the shelf amateur transmitter, a Yaesu 897D in the example video below although a $30 Chinese handheld radio will do, to create a mesh network between other Airchat users running the same software. The protocol is based on the Lulzpacket, a few bits of information that give the message error correction and a random code to identify the packet. Each node in this mesh network is defined by it’s ability to decrypt messages. There’s no hardware ID, and no plain text transmitter identification. It’s the mesh network you want if you’re under the thumb of an oppressive government.
Airchat has already been used to play chess with people 180 miles away, controlled a 3D printer over 80 miles, and has been used to share pictures and voice chats. It’s still a proof of concept, and the example use cases – NGOs working in Africa, disaster response, and expedition base camps – are noble enough to not dismiss this entirely.
Continue reading “Airchat, The Wireless Mesh Network From Lulzlabs”
[Andrew] just finished his write-up describing electronic conference badges that he built for a free South African security conference (part1, part2). The end platform shown above is based on an ATMega328, a Nokia 5110 LCD, a 433MHz AM/OOK TX/RX module, a few LEDs and buttons.
The badges form a mesh network to send messages. This allows conversations between different attendees to be tracked. Final cost was the main constraint during this adventure, which is why these particular components were chosen and bought from eBay & Alibaba.
The first PCB prototypes were CNC milled. Once the PCB milling was complete there was a whole lot of soldering to be done. Luckily enough [Andrew]’s friends joined in to solder the 77 final boards. He also did a great job at documenting the protocol he setup, which was verified using the
open source tool Maltego. Click past the break to see two videos of the system in action.
Continue reading “Building a Mesh Networked Conference Badge”