A Better Spectrum Analyzer For Your Rigol Scope

September 22, 2015 by Eric Evenchick 11 Comments

The Rigol DS1000 series of oscilloscopes are popular with hobbyists for good reason: they provide decent specs at a low price. However, their spectrum analysis abilities are lacking. While these scopes do have a Fast Fourier Transform (FFT) function, it’s limited and nearly useless for RF.

[Rich] wanted a spectrum analyzer for amateur radio purposes, but didn’t want to build his own sampling hardware for it. Instead, he wrote PyDSA, a software spectrum analyzer for Rigol DS1000 oscilloscopes. This tool uses the USB connection on the scope to fetch samples, and does the number crunching on a far more powerful PC. It’s able to plot a 16,000 point FFT at two sweeps per second when run on a decent computer.

PyDSA is a Python script that makes use of the Virtual Instrument Software Architecture (VISA) interface to control the scope and fetch the sample data. Fortunately there’s some Python libraries that take care of the protocol.

[Rich] is now able to use his scope to measure amateur radio signals, which makes a nice companion to his existing Teensy based SDR project. If you have a Rigol, you can grab the source on Github and try it out.

Circular Saw + Innovative Fence = Unique DIY Table Saw

September 17, 2015 by Dan Maloney 26 Comments

A table saw is often the first machine the aspiring woodworker wants for the shop. But even a lightweight contractor’s saw is not cheap, and a really good cabinet saw is both expensive and incredibly heavy. And any table saw is an intimidating machine that can liberate your fingers from your hand in a trice. Looking for a solution to all of these problems, [Seumas] has come up with a unique table saw conversion for a circular saw that improves safety and lowers the barrier to table saw ownership.

Flipping a low-cost circular saw upside down and attaching it to a table is old hat – we’ve seen plenty of examples of that before, including this recent post. Where [Seumas]’s idea shines is in the integration of the fence and the table. A typical fence needs to stay perfectly parallel to the blade while being dead square to the table, but still needs to be moved to adjust the width of cut. In [Seumas]’s design, the fence is fixed to the table, and the whole table slides left and right on high-pressure laminate rails. In theory, the fence will never go out of true, and the width of cut can be a lot wider than the typical table saw – an impressive 3 feet to the right of the blade.

As for safety, [Seumas] shows off quite a selection of DIY attachments in the video after the break. He builds his own Lexan blade guard, anti-kickback pawls, and stock hold-downs. Add in the little touches like shop-made clamps for locking the table, extending outfeed support, and built-in dust collection, and you can make yourself a pretty capable machine at the fraction of the cost of buying.

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A DIY Mobile Soldering Iron

September 16, 2015 by Brian Benchoff 17 Comments

Cordless soldering irons are, as a rule, terrible. A few months ago, you could pick up a cordless soldering iron from Radio Shack that was powered by AAA batteries. You can guess how well those worked. There are butane-fueled soldering irons out there that will heat up, but then you’re left without the requisite degree of temperature control.

[Xavier] didn’t want to compromise on a mobile soldering iron, so he made a desktop version portable. His mobile temperature controlled soldering iron uses the same electronics that are found in inexpensive Hakko clones, and is powered by a LiPo battery.

The soldering station controller comes directly from eBay, and a DC/DC boost converter accepts just about any DC power supply – including an XT60 connector for LiPo cells. A standard Hakko 907 iron plugs into the front, and a laser cut MDF enclosure makes everything look great. There were a few modifications to the soldering station controller that involved moving the buttons and temperature display, but this build really is as simple as wiring a few modules together.

With an off-the-shelf LiPo battery, the iron heats up fast, and it doesn’t have a long extension cord to trip over. With the right adapter, [Xavier] can use this soldering station directly from a car’s cigarette power port, a great feature that will be welcomed by anyone who has ever worked on the wiring in a car.

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How To Build A Pocket-Sized MBed Signal Generator

September 15, 2015 by Al Williams 13 Comments

Last month, I talked about how to get started with mBed and ARM processors using a very inexpensive development board. I wanted to revisit mBed, though, and show something with a little more substance. In particular, I often have a need for a simple and portable waveform generator. It doesn’t have to be too fancy or meet the same specs as some of the lab gear I have, but it should be easy to carry, power off USB, and work by itself when required.

My requirements mean I needed a slightly more capable board. In particular, I picked up a K64F board. This is very similar to the KL25Z board but has a bit more of everything–speed, memory, etc. What I really wanted, though, was the SD card slot. I did, however, do my early testing on a KL25Z, so if you have one, you can still work through the code, although standalone operation won’t be possible. The price jumps from $13 to $35, but you get a lot more capability for the price.

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Surface Mount Soldering Workshop Shares Secrets Of CM

September 12, 2015 by Mike Szczys 19 Comments

Friday afternoon I had the pleasure of sitting in on a surface mount soldering workshop. I’ve done some surface mount soldering before and am quite adept with a soldering iron, but this focused on solder paste and a hot air pencil. [Bob Cogeshall] ran the workshop and went beyond the most basic information. His experience founding Small Batch Assembly, a contract manufacturer whose offices are in the Nova Labs hackerspace, has led him to learn a lot of tricks of the trade.

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Resistance Is… There’s An Augmented Reality App For That!

September 12, 2015 by Al Williams 68 Comments

Like many engineers of a certain age I learned the resistor color code using a mnemonic device that is so politically incorrect, only Tosh might venture to utter it in public today. When teaching kids, I have to resort to the old Radio Shack standby: Big Boys Race Our Young Girls But Violet Generally Wins. Doesn’t really roll off the tongue or beg to be remembered. Maybe: Bad Beer Rots Our Young Guts But Vodka Goes Well. But again, when teaching kids that’s probably not ideal either.

Maybe you can forget all those old memory crutches. For one thing, the world’s going surface mount and color coded resistors are becoming a thing of the past. However, if you really need to read the color code, there’s at least three apps on the Google Play Store that try to do the job. The latest one is ScanR, although there is also Resistor Scanner and Resistor Scan. If you use an iPhone, you might try this app, although not being an Apple guy, I can’t give you my feedback on that one.

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Microwaving Things Outside Of The Microwave!

September 11, 2015 by James Hobson 48 Comments

DISCLAIMER: DO NOT TRY THIS AT HOME!

Ever wonder what would happen if you took a magnetron out of a microwave, strapped it to a stick, and pointed it at random everyday objects? Well, lucky for you a couple young Russians recorded their research before they presumably hurt themselves and were hospitalized, or maybe just became infertile — or caused cataracts — point is don’t do it.

They’ve taken a magnetron out of a microwave, and tied a soup can to the side of it to focus the microwaves. After discovering this, they did the next logical step — point it at various things and see what happens.

In this specific video (they have lots…) you can see them create plasma inside light bulbs, melt light bulbs, light up vacuum tubes, fluorescent bulbs, liquefy metal, and even catch a glimpse of radio waves.

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