Author Archives: Eric Evenchick

The History and Physics of Triode Vacuum Tubes

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The triode vacuum tube might be nearly obsolete today, but it was a technology critical to making radio practical over 100 years ago. [Kathy] has put together a video that tells the story and explains the physics of the device.

The first radio receivers used a device called a Coherer as a detector, relying on two tiny filaments that would stick together when RF was applied, allowing current to pass through. It was a device that worked, but not reliably. It was in 1906 that Lee De Forest came up with a detector device for radios using a vacuum tube …read more

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A Canon Lens Adapter for the Game Boy Camera

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Released in 1998, the Game Boy camera was a bit ahead of its time. This specialized Game Boy cartridge featured a 128×128 pixel CMOS sensor and took 4-color greyscale photos. The camera even rotated, allowing for selfies years before that word existed.

The fixed lens on this camera meant no zoom was possible. [Bastiaan] decided to address this shortcoming by building a Canon EF Lens Mount. The resulting build looks hilarious, but actually takes some interesting photos.

[Bastiaan] designed the mount using Rhino 3D, and printed it out on a Monoprice 3D printer. After some light disassembly, the mount can …read more

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Tracking CubeSats for $25

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CubeSats are tiny satellites which tag along as secondary payloads during launches. They have to weigh in at under 1.33 kg, and are often built at low cost. There’s even open source designs for these little spacecrafts. Over 800 CubeSats have been launched over the last few years, with many more launches scheduled in the near future.

[Thomas Cholakov] coupled a homemade cloverleaf antenna to a software-defined radio to track some of these satellites. The antenna is built out of copper-clad wire cut to the correct length to receive 437 MHz signals. Four loops are connected together and terminated to …read more

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Tiny FPGA Board Fits in Your Laptop

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There are a bunch of FPGA development boards to choose from, but how many will fit inside your laptop? The PicoEVB is a tiny board that connects to a M.2 slot and provides an evaluation platform for the Xilinx Artix-7 FPGA family.

This minimalist board sports a few LEDs, a PCIe interface, an integrated debugger, on-board EEPROM, and some external connectors for hooking up other bits and pieces. The M.2 connector provides the board with power, USB for debugging, and PCIe for user applications.

A major selling point of this board is the PCIe interface. Most FPGA boards with PCIe …read more

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Windows for Workgroups 3.11 in 2018

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It’s been 25 years since Microsoft released Windows for Workgroups 3.11. To take a trip back to the end of the 16-bit era of operating system, [Yeo Kheng Meng] got WFW 3.11 running on a modern Thinkpad.

To make things difficult, a few goals were set for the project. Obviously, this wouldn’t be much fun in a virtual machine, so those were banned. A video driver would be needed, since WFW 3.11 only supports resolutions up to 640×480 in software. Some basic support for sound would be desirable. Finally, TCP/IP networking is possible in WFW 3.11, so networking hardware would …read more

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QElectroTech: An Open Source Wiring Diagram Tool

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There’s a few open source options out there for creating electrical schematics. KiCad and Fritzing are two that will take you from schematic capture to PCB layout. However, there’s been limited options for creating wiring diagrams. Often these are created in Microsoft’s Visio, which is neither open source nor well suited for the task.

QElectroTech is an open source tool for drawing these types of diagrams. It consists of two tools: an element editor for creating schematic symbols and a diagram editor for creating your drawings. Libraries of common symbols are also included, along with the IEC 60617 standardized symbols. …read more

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This NES ROM is a ZIP of its Source

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Polyglots, in computing terms, are files have multiple valid meanings. We’ve seen some amazing examples of polyglot files in releases of The International Journal of PoC||GTFO. One example: a PDF that is also a ZIP, HTML file, and BPG image.

[Vi Grey] was inspired by PoC||GTFO’s release of a PDF/ZIP/NES ROM hybrid file for issue 0x14. Using a different method, [Vi] created a file which is both an NES ROM and ZIP, where the full contents of the ZIP are stored in the NES ROM.

When PoC||GTFO created their NES ROM polyglot, they stuck most the information outside the bounds …read more

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Tomu: A Microcontroller for Your USB Port

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Looking for a ultra tiny development board? Tomu is an ARM Cortex M0+ device that fits inside your USB port. We’ve seen these in person, and they’re tiny.

There’s a few commercial devices in this form factor on the market. For example, the Yubikey Nano emulates a keyboard to provide codes for two-factor authentication. The Yubikey’s tiny hardware does this job well, but the closed-source device isn’t something you can modify.

Tomu is a new device for your USB port. It sports a Silicon Labs EFM32 microcontroller, two buttons, and two LEDs. This particular microcontroller is well suited to …read more

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A Fully Featured, Fifty Dollar QRP Radio

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QRP radio operators try to get maximum range out of minimal power. This term comes from the QRP Q-code, which means “reduce power.” For years, people have built some very low-cost radios for this purpose. Perhaps the best known QRP kit is the Pixie, which can be found for less than $3 on eBay.

The QRX is a new DIY QRP radio kit from QRP Labs. Unlike the Pixie, it has a long list of features. The QRX operates on the 80, 60, 40, 30, 20, or 17 meter bands at up to 5W output power. The display provides tuning …read more

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DIY USB Power Bank

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USB power banks give your phone some extra juice on the go. You can find them in all shapes and sizes from various retailers, but why not build your own?

[Kim] has a walkthrough on how to do just that. This DIY USB Power Bank packs 18650 battery cells and a power management board into a 3D printed case. The four cells provide 16,000 mAh, which should give you a few charges. The end product looks pretty good, and comes in a bit cheaper than buying a power bank of similar capacity.

The power management hardware being used here appears …read more

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