RF Shield Turns Arduino (And PC) Into Shortwave Radio

February 14, 2020 by Al Williams 10 Comments

Microcontrollers tend to consume other kinds of electronics. A project you might once have done with a 555 now probably has a cheap microcontroller in it. Music synthesizers? RC controllers? Most likely, all microcontroller-based now. We always thought RF electronics would be immune to that, but the last decade or two has proven us wrong. Software-defined radio or SDR means you get the RF signal to digital as soon as possible and do everything else in software. If you want an introduction to SDR, Elektor now has an inexpensive RF shield for the Arduino. The Si5351-based board uses that oscillator IC to shift RF signals down to audio frequencies and then makes it available to the PC to do more processing.

The board is available alone or as part of a kit that includes a book. There’s also a series of Elektor articles about it. There’s also a review video from Elektor about the board in the video, below.

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PCB Tesla Coil Is Perfect Desk Toy

October 30, 2017 by Tom Nardi 43 Comments

A Tesla coil easily makes it to the top spot on our list of “Mad Scientist” equipment we want for the lab, second only to maybe a Jacob’s Ladder. Even then, it’s kind of unfair advantage because you know people only want a Jacob’s Ladder for that awesome sound it makes. Sound effects not withstanding, it’s Tesla coil all the way, no question.

Unfortunately, winding your own Tesla coil is kind of a hassle. Even on relatively small builds, you’ll generally need to setup some kind of winding jig just to do the secondary coil, which can be a project in itself. So when [Daniel Eindhoven] sent his no-wind Tesla coil into the tip line, it immediately got our attention.

The genius in his design is that the coils are actually etched into the PCB, completely taking the human effort out of the equation. Made up of 6 mil traces with 6 mil separation, the PCB coil manages to pack a 25 meter long, 160 turn coil into an incredibly compact package. As you might expect, such a tiny Tesla coil isn’t exactly going to be a powerhouse, and in fact [Daniel] has managed to get the entirely thing running on the 500 mA output of your standard USB 2.0 port.

In such a low-power setup, [Daniel] was also able to replace the traditional spark gap pulse generator with a PIC18F14K50 microcontroller, further simplifying the design. An advantage of using a microcontroller for the pulse generator is that it’s very easy to adjust the coil’s operating frequency, allowing for neat tricks like making the coil “sing” by bringing its frequency into the audible range.

For those looking to build their own version, [Daniel] has put the PCB schematic and firmware available for download on his site. He also mentions that, in collaboration with Elektor magazine, he will be producing a kit in the near future. Definitely something we’ll be keeping an eye out for.

Incidentally, this isn’t the first time [Daniel] has demonstrated his mastery of high voltage. He ~~scared~~ impressed us all the way back in 2010 with his 11,344 Joule capacitor bank, perfect for that laptop-destroying rail gun you’ve been meaning to build.

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Converting A Weather Station Kit For Wireless Data Harvesting

January 15, 2013 by Mike Szczys 6 Comments

converting-weather-station-for-wireless-data-collection

Everyone loves getting something you can play with as a Christmas gift. [Thomas] was the lucky recipient of an Elektor USB weather station kit. But the fun didn’t end once he had assembled everything. He went on to hack the device for wireless data collection.

Shown above is the weather station board connected to the transmitter. The red board with a tiny antenna to the right is a Rovio RN-VX module. It is capable of transmitting serial data to its twin on the receiving end of the setup. The weather station is pretty easy to connect to the transmitter since it feeds serial data to an FTDI USB chip. [Thomas] simply connected power and ground, then added a jumper from the board’s TX pin to the Rovio’s RX pin. The receiving end uses a serial-to-USB converter — getting a signal for its RX pin from the TX pin on the Rovio receiver board.

We know from other projects that these radio modules can connect to a WiFi AP. Perhaps a future revision of [Thomas’] hack will allow the weather station to communicate with his server over the network, doing away with the need for a standalone receiver.