HamShield Puts Your Arduino On The Radio

Anybody can grab a USB TV tuner card and start monitoring the airwaves, but to get into the real meat of radio you’ll need your amateur radio license. Once you have that, the bandwidth really opens up… if you can afford the equipment. However, [spaceneedle] and friends have dramatically lowered the costs while increasing the possibilities of owning a radio by creating this ham radio shield for the Arduino.

The HamShield, is a versatile shield for any standard Arduino that allows it to function like an off-the-shelf radio would, but with a virtually unlimited number of functions. Anything that could be imagined can be programmed into the Arduino for use over the air, including voice and packet applications. The project’s sandbox already includes things like setting up mesh networks, communicating over APRS, setting up repeaters or beacons, monitoring weather stations, and a whole host of other ham radio applications.

HamShield operates on a wide range of frequencies and only uses a 250 mW amplifier. The power draw is small enough that the HamShield team operated it from a small solar panel, making it ideal for people in remote areas. The project is currently gathering funding and has surpassed their goal on Kickstarter, branding itself appropriately as the swiss army of amateur radio. The transceiver seems to be very robust, meaning that the only thing standing in the way of using this tool is simply writing the Arduino code for whatever project you want to do, whether that’s as a police scanner or even just a frequency counter. And if you want to follow along on hackaday.io, the project can be found here.

Continue reading “HamShield Puts Your Arduino On The Radio”

Airchat, The Wireless Mesh Network From Lulzlabs

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”

Extending the range of wireless weather stations with walkie talkies

[Roel] wanted to put a wireless weather station in his greenhouse. Even though the weather station was supposed to transmit over fairly long distances, the geometry of his back yard and a few stone walls killed the radio signal even after putting a good antenna on the receiving side of his wireless weather station setup. Wanting to get his weather station working, [Roel] did the sensible thing and built a packet radio setup out of a pair of walkie talkies, greatly increasing the range of his weather station.

This build comes after [Roel] spent a great deal of time reverse engineering the wireless protocol of his Thierry Mugler weather station. With a little bit of code, [Roel] is able to get the current temperature and humidity reading into his Linux box. This system relies on the transmitter inside the weather station, so the system falls apart over any sufficiently large distance.

To increase the range of his weather station, [Roel] took his existing hardware and added a pair of inexpensive FRS walkie talkies. The build uses the hardware from his previous build to get the radio data from the weather station. This data is sent over to an ATmega88 where it’s converted to packet radio and sent over the walkie-talkie. On the receiving side, the output of a second walkie-talkie is piped into the Linux soundmodem app (link, but it’s down as of this writing) where it’s decoded. Sending the received data to gnuplot makes a very nice graph of the temperature and humidity.

[Roel] put the code for both the tx and rx sides of the build up on his build page. Very nice work that uses very inexpensive hardware.