Category: Other

Migou: A Low-Power Hybrid Radio Platform

Thank you to Ramiro Utrilla Gutiérrez a PhD Candidate researcher at Universidad Politécnica de Madrid for writing in and sharing his research groups work on a low power SDR radio platform called "Migou". The basic idea is to combine software defined radio which is flexible but power hungry, with less flexible but power efficient hardware radios. The design files and BOM are creative commons licensed, and free to download. The radio is capable of operating in the 433 MHz, 868 MHz and 2.4 GHz bands at sample rates of up to 4 MSPS in SDR mode. Ramiro writes:

I'm the main developer of the MIGOU platform. This platform uses the Microchip AT86RF215 transceiver (like TinySDR and iotSDR) and a Microchip SmartFusion2 flash-based FPGA SoC.
 
The particularity of our work is what we have called the hybrid radio approach, which proposes to provide low-resource devices with the ability to operate both as a current mote, using a hardware transceiver, and as an SDR system. This is possible using only the AT86RF215 transceiver. With these capabilities, hybrid radio end-devices can exploit the SDR hardware flexibility for those sporadic tasks that strictly require it, and still benefit from the energy efficiency of hardware transceivers for all other tasks.
 
Our platform is not a commercial product, it is an open-source research tool. If you are interested, you can read more about our work in this article in Sensors journal, where we present the hybrid radio approach and the MIGOU platform, and in this article in IEEE Access journal, where we approach a Cognitive Radio problem from the perspective of our hybrid radio platform. Both articles are also open access.

The B105 Electronic Systems Lab also appear to have a website for the design which provides a summary:

MIGOU is a low-power wireless experimental platform designed to simultaneously address the energy-efficiency requirements of resource-constrained end-devices and the hardware flexibility demanded by the current Cognitive Radio (CR) and edge computing paradigms. This platform relies on the SmartFusion2 SoC that integrates an ARM Cortex-M3 processor and a flash-based FPGA, where high-speed processing tasks can be offloaded and computed more efficiently via hardware acceleration. In addition, at the radio level, the platform can operate both as a traditional node, which demands lower energy resources and development time, and as a Software-Defined Radio (SDR) system, which allows for the implementation of custom CR features. Moreover, the ability to dynamically switch between these two modes of operation opens the possibility for developing new hybrid strategies, taking advantage of both the flexibility offered by the SDR and the efficiency of the transceiver’s highly optimized baseband cores.

The power consumption of our platform was measured in transmit, receive, and sleep modes. These measurements were compared with the corresponding ones of other representative tools and systems: YetiMote, a traditional IoT end-device; MarmotE SDR, a low-power SDR system; and B200mini and B210 USRPs, two widely used high-performance SDR platforms. Moreover, all these devices were compared in terms of their hardware features. The results obtained confirmed that a state-of-the-art tradeoff between hardware flexibility and energy efficiency was achieved. These features will allow researchers to develop appropriate solutions to current end-devices’ challenges, and to test and evaluate them in real scenarios.

Migou: Low-Power Hybrid Radio Platform

Evil Crow RF: An Open Source CC1101 Based Device for Pentesting

The CC1101 is a popular RF silicon chip as it can handle many common digital modulation modes such as OOK/ASK, FSK, GFSK, and MSK within it's hardware. It is not a software defined radio, but rather a hardware radio that can be easily software controlled. Over the years we've seen the CC1101 and it's cousin the CC1111 with embedded microcontroller used in several pentesting/RF reverse engineering tools such as the Flipper Zero, Yard Stick One and PandwaRF.

There is now a new open source CC1101 implementation called the "Evil Crow RF". This hardware marries two CC1101 modules with an ESP32 WiFi and Bluetooth microcontroller. It is capable of operating in the 300 MHz - 348 MHz, 387 MHz - 464 MHz and 779 MHz - 928 MHz bands. As it has two CC1101 modules it can receive or transmit on two different frequencies at the same time. 

The firmware running on the ESP32 allows you to control the device via a simple web interface. Currently built in are interfaces for receiving, transmitting and brute forcing.

The device hardware is completely is open source so anyone can build it, however the creators are selling a ready to use version on Aliexpress, however at the time of this post it appears to be out of stock.

Over on Twitter creator @JoelSernaMoreno has uploaded a short video of it working.

The Evil Crow RF Open Source CC1101 Based Radio

DragonOS: Now with RF Propagation and Calculation Tool

DragonOS is a ready to use Ubuntu Linux image that comes preinstalled with multiple SDR software packages. In the recent R14 Preview update, Aaron, the creator of DragonOS has added a new very useful RF propagation and calculation tool. The tool works in conjunction with elevation data to calculate the theoretical signal propagation of a transmitter.

The tool is provided by the open source Signal Server software package, which is based on the original SPLAT! software by John Magliacane (KD2BD). Aaron has also provided a video that demonstrates the software in action, shows how to use it, and explains his future plans for making it easier to use.

This video is a preview of a new RF Propagation and Calculation feature provided by Signal Server. Additionally, custom web server scripts by Dr. Bill Walker, will also be included in DragonOS Focal R14 in the near future. There's a lot of moving parts, but once complete, all you "should" have to do is download, convert, and place the SRTM elevation data for the areas needing coverage calculations in the /usr/src/SDF directory. In the meantime, I'd recommend reading up on all the below material. I've been reading a lot and still don't understand it all!

DragonOS Focal R14 Preview w/ Signal Server + RF Propagation Web Server (SPLAT!, Dr. Bill Walker)

Scikit-RF: An Open Source RF Engineering Package in Python

Thank you to Alexander, the original author of scikit-rf (aka skrf) for writing in and sharing his project which he believes may be of interest to some readers. Scikit-rf is an open source, BSD-licensed RF/Microwave engineering package implemented in Python. The package can be used for simulating various RF components such as transmission lines and waveguides, as well as creating models from data measured from real components which can then be used in a simulated system.

As an example, Alexander shows how you can plot Touchstone data on a Smith chart in 3 Python lines.

    > import skrf as rf
    > ntwk = rf.Network('ring slot.s2p')
    > ntwk.plot_s_smith()
 

Alexander also writes:

With skrf you can also do all your own calibrations offline, time gate when you feel like it, connect and manipulate microwave networks and plot all the results. And... you can read all the source code!, which is really important for proto-typing and research. Check out the Documentation or Examples for a more in-depth look at scikit-rf.

Here are a couple links to projects using scikit-rf

History 

scikit-rf was created in 2009 by Alex Arsenovic while he was a graduate student at the University of Virginia’s millimeter wave research lab in 2009. scikit-rf is licensed under the BSD License and is currently being actively developed by a group of volunteers on Github.

 

PiccoloSDR: A Simple SDR From a Raspberry Pi Pico

The Raspberry Pi Pico is a $4 microcontroller board. Recently radio amateur Luigi Cruz discovered that the ADC on the Pico could be used as a simple direct sampling software defined radio, with a bandwidth of 250 kHz. The idea is that the ADC data is made available to a PC connected to it's USB port via emulated TCP/IP protocol. On the PC side, GNU Radio is then used to process the received ADC data, turning it into an SDR.

Applications of a direct sampling SDR with only 250 kHz are limited, as it's only possible to receive up to the LF band, and there are not many signals that low in frequency. However, it is an interesting project that can be used to demonstrate a simple SDR. If you're interested in trying it out, the code is available over on GitHub.

PiccoloSDR Project - Using the Raspberry Pi Pico RP2040 as an SDR - First Test with GNU Radio.

[Also seen on Hackaday]

Army Builds Wideband DC to 20 GHz Quantum Receiver

Back in July 2019 we posted about a new development in radio technology known as "Atomic Radio" or "Quantum Radio". In that post we discussed an article that explained the concept and science behind the idea and noted how some researchers described the possibility of a very wideband capable receiver.  

Recently the US Army has described how they built a quantum radio that can receive from DC to 20 GHz. If you're interested in the science, the paper is published in the Journal of Physics B: Atomic, Molecular and Optical Physics and it is available on sci-hub. The radio uses something called a Rydberg sensor which they describe below. 

The Rydberg sensor uses laser beams to create highly-excited Rydberg atoms directly above a microwave circuit, to boost and hone in on the portion of the spectrum being measured. The Rydberg atoms are sensitive to the circuit's voltage, enabling the device to be used as a sensitive probe for the wide range of signals in the RF spectrum.

Army researcher Kevin Cox notes how this is the first implementation that can operate over such a wide frequency range:

"All previous demonstrations of Rydberg atomic sensors have only been able to sense small and specific regions of the RF spectrum, but our sensor now operates continuously over a wide frequency range for the first time," said Dr. Kevin Cox, a researcher at the U.S. Army Combat Capabilities Development Command, now known as DEVCOM, Army Research Laboratory. "This is a really important step toward proving that quantum sensors can provide a new, and dominant, set of capabilities for our Soldiers, who are operating in an increasingly complex electro-magnetic battlespace."

Quantum radios may be one of the next big leaps in radio technology. However as they require lasers and the space of a small laboratory the technology will probably be restricted to the military and institutions for the time being.

A Rydberg sensor setup (LEFT), The experimental setup for a Rydberg Quantum Radio Receiver (RIGHT)

RF Power Snitch: RF Power Measurement Companion for Protecting RF Equipment

Thank you to Majodi Ploegmakers who wrote in and wanted to share a product he's created that might be useful for some RF enthusiasts. The product is called the "RF Power Snitch", and is a tool used to quickly measure RF input power to determine if input power from a signal source is too strong and could damage measurement equipment such as an SDR or NanoVNA. The product is not yet for sale, but Majodi has an availability notification signup page.

NickStick Design Announces - RF Power Snitch –
“Your RF Measurement Companion”

The Netherlands: Today, NickStick Design, an electronics design company for Makers, announced their RF Power Snitch. After a successful launch of SwarmDrive through Crowd Supply last year, NickStick Design went on and designed another useful tool for makers in the RF (Radio Frequency) domain this time.

Of the company’s recent crowd funding campaign, Majodi said, “We were very pleased with the interest our last, somewhat niche, product received. It spurred us on to develop and realize our next idea”.

Today, the RF domain has become accessible to everyone through affordable tools that many could only dream of before. The only tool missing though, is a simple device for checking the, potential, destructive power of the signals one would want to analyze. Because, although tools like the TinySA, NanoVNA or SDR devices are extremely affordable today, for a maker it is still an investment worth protecting.

That’s why our goal was to develop a low-cost companion device that can help makers and experimenters (especially beginners) in the RF domain to gain insight in the power levels of a signal before hooking things up to their valuable test equipment. As an extra to this we also made it possible to attach an MCU for doing power readings and plotting.

Website: https://powersnitch.nickstick.nl

The RF Power Snitch
The RF Power Snitch

TinySDR: An OpenSource SDR for IoT Applications

We recently came across a relatively new SDR design that is called "TinySDR". The design is entirely open source and is focused on helping analyze wireless Internet of Things (IoT) applications. Currently the device is not manufactured and sold by anyone, but the open source Altium Designer PCB files, BOM and firmware can be found on their GitHub.

Over on hackster.io Tom Fleet has also given the TinySDR a writeup. He notes that the design is based around the AT86RF215 transceiver chip and a Lattice Semiconductor ECP5 FPGA. The board is split into an input for 2.4 GHz and a sub-GHz input. On the GitHub there are currently demo files available to turn the SDR into LoRa and FSK modulators.

The TinySDR