I need someone to explain this to me.

A Modular 1GHz Spectrum Analyzer


[MrCircuitMatt] has been doing a lot of radio repair recently, quickly realized having a spectrum analyzer would be a useful thing to have. Why buy one when you can build one, he thought, and he quickly began brushing up on his RF and planning out the design of a 1000 MHz spectrum analyzer

The project is based on Scotty’s Spectrum Analyzer, a sweep-mode, modular 1GHz spectrum analyzer that is, unfortunately, designed entirely in ExpressPCB. [Matt] didn’t like this proprietary design software tied to a single board house. The basic building blocks of [Scotty]‘s spectrum analyzer were transferred over to KiCAD, the boards sent off to a normal, Chinese board house.

In the second video, [Matt] goes over the design of the control board, a small module that connects the spectrum analyzer to the parallel port of a PC. There’s a lot of well thought out design in this small board, a good thing, too, since he’s powering his VCO with a switched mode supply. The control board has a 32-bit I/O, so how’s he doing that with a parallel port, what is ultimately an 8-bit port? A quartet of 74ACT573, a quad buffer with latch enable. Using the eight data lines on the parallel port allows him to toggle some pins while the ancient pins on the parallel bus – Strobe, Select Printer, and Line Feed control the latches on each of the buffers. This gives him the ability to write to 32 different pins in his spectrum analyzer with a parallel port.

Right now, [Matt] is wrapping up the construction of his control board, with the rest of the modules following shortly. He thinks the completed analyzer might even be cheaper than a professional, commercial offering, and we can’t wait to see another update video.

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Not Your Typical ATX Power Supply Hack

Not Your Average Power Supply Hack

Power supplies are essential for at home tinkering and electronics hacking. Unfortunately, they’re really quite expensive, and a bit out of reach for most hobbyists. Computer ATX power supplies are a cheap alternative, although they usually tend to lack the features of real bench power supplies… unless you hack yours like [Mark Schoonover]!

When [Mark] set out on this project he wanted to use as many recycled components as possible, but still come up with an extremely functional bench top power supply. He snagged a 500W ATX power supply from one of his kid’s old desktop PC’s, grabbed some old wall-warts for individual current limited supplies (apparently ATX PSU’s don’t have 5V rails anymore?), and put it all into a nice big project box.

He’s even thrown in a voltage regulator with current metering and a nice set of 7-segment displays!

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Augmented Laser Cutter Removes Design Technology Barriers

augmented laser

Laser cutters, 3D printers, CNC routers — they’re all great technology in the right hands, but unfortunately the learning curve sometimes puts would-be makers at a distance.  [Anirudh] from MIT’s Media Lab is attempting to break down at least one of those barriers with his augmented laser cutter system called, Clearcut.

The system consists of a webcam, a projector, and a semi transparent work space on top of the laser cutter. By placing objects on the surface, the webcam can identify them, duplicate them with the projector, and then laser engrave them. In addition to the “copy and paste” idea of this, you can also use infrared emitting pens to physically draw your design on the work surface to be engraved. It starts to bridge the gap between complex CAD and pencil and paper, something anyone is capable of.

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GPIB To USB, With A Python API


If you’re not so daft as to think Arduino-based oscilloscopes and multimeters are actually useful for all but the simplest tests and measurements, you just might have some big iron sitting around your workbench from the likes of HP, or Tektronix. You might have noticed a strange port on the back of these machines, labeled GPIB or IEEE-488. This is the standard interface for these devices, and if you’ve ever priced out a USB to IEEE-488 converter, you can see why [Steven] thought it would be cheaper to build his own.

This build is an update to an earlier version we saw a few years ago. Since then, [Steven] has taken some advice from the community and replaced a bunch of resistors with proper GPIB line driver ICs, and generally cleaned up the firmware.

Because a USB to GPIB adapter is only one small part of the tools necessary to connect these old measurement devices to a modern computer, [Steven] has also been working on InstrumentKit. It’s a Python library that takes all the standardized instrument commands and wraps them up in an easy to use API. You can check out the docs for InstrumentKit here, or just look through the board files and firmware on the Github

Wind Tunnel Testing Now Available To The Common Man

DIY Wind Tunnel

If you are in the market for a DIY wind tunnel the folks over at sciencebuddies.org have got you covered. They have done a great job documenting how they built their own wind tunnel. Most of the structure is made of plywood with the test chamber is made of plexi-glass so that the operator can visually observe what is happening during a test. A common gable-mount fan provides the air flow, you may have one installed in your attic to keep it cool. The only non-widely available components are the force sensors that feed data to a computer for logging.

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Circular Saw Cuts Balls… Wooden Balls, Don’t Worry

Wood Sphere made with circular saw

Ever wonder how wood spheres are made? Normally they are made on a wood lathe with some fancy jigs and fixtures. [Izzy Swan] set out to bring wood sphere manufacturing to the masses by designing an inexpensive machine that uses a standard circular saw to carve a block of wood into a sphere.

Here’s how it works: a piece of wood is held in a wood fixture and spun using a hand drill. The fixture and drill are mounted to a wooden ring that rotates about a perpendicular axis. The user manually moves the entire assembly back and forth about that second axis while spinning the drill. Meanwhile, a circular saw is moved closer and closer to the soon-to-be-sphere, nibbling away little by little. After most of the material has been cut from the block of wood, it is removed from the fixture and spun 90 degrees to cut the two remaining nubs. The end result is a pretty nice looking sphere.

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Rechargeable Work Lamp Brightens Your Night

Portable power station has DC, AC and Light on board.

Most of us tinkerers will at some point find ourselves needing electrical power in a remote area. Cordless tools are an option, but what if you need more than that? [Garage Monkey San] set out to solve this problem by creating a portable power station that has on-board AC outlets, 12v and 5vdc outputs and an integrated spot light.

This project is housed in a plastic ammo case that’s large enough to contain all of the necessary parts and has a convenient carrying handle. The 12vdc sealed lead acid battery power source is kept topped off by a car battery float charger. Light is provided by an LED off road fog lamp mounted to the top of the case that has a small appetite for power, ensuring long battery life. An easy addition at this point was a 12v car accessory outlet which only adds to the versatility of the project.

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