Hackaday Superconference: An Analog Engineer Dives Into RF

Those of us who work with electronics will usually come to the art through a particular avenue that we master while imbibing what we need from those around it. For example, an interest in audio circuitry may branch into DSP and microcontrollers as projects become more complex. Some realms though retain an aura of impossibility, a reputation as a Dark Art, and chief among them for many people is radio frequency (RF). Radio circuitry is often surprisingly simple, yet that simplicity conceals a wealth of complexity because the medium does not behave in the orderly manner of a relatively static analogue voltage or a set of low-frequency logic levels.

Chris Gammell is a familiar face to many Hackaday readers for his mastery of much electronic trickery, so it comes as something of a surprise to find that RF has been one of the gaps in his knowledge. In his talk at the Hackaday Superconference he took us through his journey into RF work, and the result is a must-watch for anyone with a curiosity about radio circuitry who didn’t know where to start.

via Hackaday Superconference: An Analog Engineer Dives Into RF — Hackaday

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Weird World of Microwaves Hack Chat

Join us on Wednesday, December 18 at noon Pacific for the Weird World of Microwaves Hack Chat with Shahriar Shahramian! We’ve been following him on The Signal Path for years and are excited to pick his brain on what is often considered one of the dark arts of electronics.

No matter how much you learn about electronics, there always seems to be another door to open. You think you know a thing or two once you learn about basic circuits, and then you discover RF circuits. Things start to get a little strange there, and stranger still as the wavelengths decrease and you start getting into the microwave bands. That’s where you see feed lines become waveguides, PCB traces act as components, and antennas that look more like musical instruments.

via Weird World of Microwaves Hack Chat — Hackaday

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Hackaday Prize Entry: Sub Gigahertz RF

For his Hackaday Prize entry, [Adam] is working on an open source, extensible 915 and 433 MHz radio designed for robotics, drones, weather balloons, and all the other fun projects that sub-Gigaherts radio enables.

The design of this radio module is based around the ADF7023 RF transceiver, a very capable and very cheap chip that transmits in the usual ISM bands. The rest of the circuit is an STM32 ARM Cortex M0+, with USB, UART, and SPI connectivity, with support for a battery for those mobile projects.

via Hackaday Prize Entry: Sub Gigahertz RF — Hackaday

Hackaday Prize Entry: Sub Gigahertz RF

Mesh networking for sensor grids

Mesh networking board by Daniel on Hackaday.io:

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Low-power mesh networking for small sensor grids

Tiny MQTT-interoperable broadcast mesh networking with simple radios

This project is a low-resource mesh networking stack and mote with battery-powered routers based on state synchronization. The target is for the stack to use less than 2kb SRAM. Nodes use low power listening and an adaptive gossip protocol to synchronize key/values pairs with each other without relying on explicit routing or per-node addressing.

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For example, a light might transmit (/lamp, {“state”:”on”}) to the mesh. Write (/lamp, {“state”:”off”}) to the mesh, and the lamp application will notice. The powerful but simple state synchronization primitive allows you to update the state of the mesh to update the world, and update the state of the world to express the same on the mesh. Trivially bridged to a private MQTT server and managed with off-the-shelf MQTT applications.

The design files and source code are available on Bitbucket:

dholth/mesh

Mesh networking for sensor grids

Pidgeon 1 Sub-GHz Radio

Pidgeon 1 on Crowd Supply is a sub-GHz radio with 500 mW transmission power, RS485 networking interface and a STM32F0 microcontroller:
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Crowd Supply: Pidgeon 1

No more restrictions from high level software! Access the lowest level of digital radio transmission with this programmable sub-GHz wireless module.

Hardware Specifications:

  • Radio – CC1120 + CC1190
  • Controller – STM32F051K6
  • FTDI USB interface – FT234XD-R
  • RS485 interface – LTC2850IDD
  • Buck converter – RT8010GQW
  • SMA connector for antenna
Pidgeon 1 Sub-GHz Radio

DTV Tuner Breakout for SDR

Eric Brombaugh designed this breakout board for the Rafael Microelectronics R820T2 Advanced Digital TV Silicon Tuner chip:

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R820T2 Breakout

This is the same chip used in most all of the RTL-SDR dongles, as well as the Airspy and numerous other radios. The chip is a versatile front-end with reasonable sensitivity and wide tuning range.

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The design presented here is almost an exact implementation of the Mfg’s suggested demo design from the datasheet, implemented on the OSHpark 4-layer PCB process and provides a simple 4-pin interface with power, ground and I2C bus for controlling the tuner. A broad-band RF input and 10MHz IF output are provided on SMA connectors.

The breakout PCB design and STM32F0 firmware for the Rafael R820T2 tuner chip are shared on GitHub:

screenshot-at-2017-02-14-20-58-40 emeb/r820t2

 

emeb has shared project on OSH Park:

r820t2_breakout v0.1

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Order from OSH Park

DTV Tuner Breakout for SDR

PCB Design Guidelines to Minimize RF Transmissions

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 writes on Hackaday:

PCB Design Guidelines to Minimize RF Transmissions

There are certain design guidelines for PCBs that don’t make a lot of sense, and practices that seem excessive and unnecessary. Often these are motivated by the black magic that is RF transmission. This is either an unfortunate and unintended consequence of electronic circuits, or a magical and useful feature of them, and a lot of design time goes into reducing or removing these effects or tuning them.

You’re wondering how important this is for your projects and whether you should worry about unintentional radiated emissions [..]

Another good guide is Michael Ossmann’s simple RF design rules:

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PCB Design Guidelines to Minimize RF Transmissions