Sometimes the best projects are the simple, quick hits. Easily designed, fast to build, and bonus points for working right the first time. Such projects very often lead to bigger and better things, which appears to be where this low-power temperature beacon is heading.
In the world of ham radio, beacon stations are transmitters that generally operate unattended from a known location, usually at limited power (QRP). Intended for use by other hams to determine propagation conditions, most beacons just transmit the operator’s call sign, sometimes at varying power levels. Any ham that can receive the signal will know there’s a propagation path between the beacon and the receiver, which helps in making contacts. The beacon that [Dave Richards (AA7EE)] built is not a ham beacon, at least not yet; operating at 13.56 MHz, it takes advantage of FCC Part 15 regulations regarding low-power transmissions rather than the Part 97 rules for amateur radio. The circuit is very simple — a one-transistor Colpitts oscillator with no power amplifier, and thus very limited range. But as an added twist, the oscillator is keyed by an ATtiny13 hooked to an LM335 temperature sensor, sending out the Celsius and Fahrenheit temperature in Morse every 30 seconds or so. The circuit is executed in Manhattan style, which looks great and leaves plenty of room for expansion. [Dave] mentions adding a power amp and a low-pass filter to get rid of harmonics and make it legal in the ham bands.
Beacons are just one of the ways for hams to get on the air without talking. Another fun way to analyze propagation is WSPR, which is little like an IoT beacon.
Continue reading “Temperature Sensor and Simple Oscillator Make a Value-Added HF Beacon”
John Perry Barlow, founding member of the Electronic Frontier Foundation and Freedom of the Press Foundation, died on February 7th, 2018. To say that he left his mark on the Internet, and by extension modern culture, is something of an understatement. He may not be a household name, but between this activism (online and off), lectures, written work, and various entrepreneurial projects, his 70 years of life were surely not wasted. Barlow was once quoted as saying “I want to be a good ancestor”, and by pretty much any metric it would seem he made good on that goal.
To mark his passing, [Moritz Metz] came up with a rather unusual memorial. Using a bit of code on an ESP8266 board, he created a device that would broadcast out Barlow’s “A Declaration of the Independence of Cyberspace” line-by-line in the form of 228 WiFi SSIDs. Perhaps not the most effective way to get Barlow’s words out to the people, but we’ll give him extra points for style.
The code itself is based on FakeBeaconESP8266, which as the name implies, allows the user to create fake WiFi networks. to broadcast the manifesto of your choosing, you need only add in the appropriate
sendBeacon() lines at the bottom of the code. It would appear that prefixing each line with a number is required to make devices scanning for networks show the lines of text in proper sequence. At least on the devices demoed, anyway.
Just to be clear: you should definitely not do this. Jamming up the local environment with a bunch of fake networks is a pretty terrible idea. But as a memorial for a man who occasionally claimed to be an anarchist, you could do worse. Plus we have to admit “Giants of Flesh and Steel” is an awesome name for a network.
Continue reading “ESP8266 Broadcasts Memorial WiFi Spam”
An ultrasonic beacon is an inaudible sound with encoded data that can be used by a listening device to receive information on just about anything. Beacons can be used, for example, inside a shop to highlight a particular promotion or on a museum for guided tours where the ultrasonic beacons can encode the location. Or they can be used to track
people consumers. Imagine if Google find outs… oh, wait… they already did, some years ago. As with almost any technology, it can be used to ‘do no harm’ or to serve other purposes.
Researchers from the Technische Universitat Braunschweig in Germany presented a paper about Ultrasonic Side Channels on Mobile Devices and how can they be abused in a variety of scenarios , ranging from simple consumer tracking to deanonymization. These types of ultrasonic beacons work in the 18 kHz – 20 kHz range, which the human being doesn’t have the ability to hear, unless you are under twenty years old, due to presbycusis. Yes, presbycusis. This frequency range can played via almost any speaker and can be picked up easily by most mobile device microphones, so no special hardware is needed. Speakers and mics are almost ubiquitous nowadays, so there is a real appeal to the technology.
Continue reading “Ultrasonic Tracking Beacons Rising”
While faking BLE advertising beacons using an nRF24L01+ module is nothing new, it’s become a heck of a lot easier now that [Pranav Gulati] has written some library code and a few examples for it.
[Pranav]’s work is based on [Dmitry Grinberg]’s epic bit-banging BLE research that we featured way back in 2013. And while the advertisement channel in BLE is limited in the amount of data it can send, a $1 nRF24 module and a power-thrifty microcontroller would be great for a battery-powered device that needs to send small amount of data infrequently for a really long time.
We’re not 100% sure where [Pranav] is going to take this project. Honestly, the library looks like it’s ready to use right now. If you’ve been holding off on making your own BLE-enabled flock of birds, or even if you just want to mess around with the protocol, your life has gotten a lot easier.
It is reasonably easy to make a microcontroller spit out some Morse code. What makes [pavlin’s] take on this project interesting is that it resides on a tiny USB board with an ARM processor. The design for the board is available with single-sided artwork suitable for production using simple methods like toner transfer.
The STM device has a built-in USB bootloader. It can also act as a serial port, which makes the project very simple. The only external parts are a speaker and an optoisolator. The program provides a command line interface over the serial port that you can use to program the message and set other options like speed and the delay between messages. The code is available on GitHub.
You might argue that a beacon shouldn’t need a USB port, and we’ve seen an alternative that fits the bill. If you want a much larger Arduino-based keyer, we’ve seen those, too.
[m0xpd] got his hands on an inexpensive AD9850 DDS Module from eBay but needed a way to control it. He took inspiration from the projects that used a PIC microcontroller, but decided to add his own twist by using a Raspberry Pi to build a multi-mode beacon transmitter.
At the center of this breadboarded circuit lies the green AD9850 module. To its left is a level converter he built to get the 3.3V levels from the RPi board to work with the rest of the 5V hardware. The signal then feeds into a QRP amplifier and a low pass filter.
He didn’t start from square one when it came time to write the code for the RPi. Instead he grabbed an Arduino sketch for the very same DDS and ported it over to Python. The first test signal was his call sign sent in Morse code at QRSS speeds. But he also managed to get Hellschreiber messages working, making it a multiple-mode device.
[via Solder Smoke]
Ham skills prevail in this year’s LayerOne badge hacking contest. [Jason] was the winner with this Morse Code beacon hack.He got a head start on the competition after seeing our preview feature on the badge hardware development. It got him thinking and let him gather his tools ahead of arrival.
The hardware is segregated into two parts of the board. The lower portion is a take on the Arduino, and the upper portion is a wireless transmitter meant to control some cheap RC cars. [Jason] figured this was perfect for conversion as a CW beacon (continuous wave is what Morse Code is called if you’re a ham). The first issue he encountered was getting the badge to play nicely with the Arduino IDE. It was setup to run Slowduino firmware which uses the internal oscillator. [Jason] soldered on his own crystal and reflashed the firmware. He found that the transmitter couldn’t be directly keyed because of the shifting used in the RC car protocol. He cut the power to the transmitter, and found that it could be more accurately keyed by injecting power to one of the other pins. Check out the video after the break for a better explanation of his technique.
Continue reading “Morse code beacon wins the LayerOne badge hacking contest”