Putting A Poor Man’s Vector Analyzer Through Its Paces

March 29, 2018 by Dan Maloney 20 Comments

If anything about electronics approaches the level of black magic, it’s antenna theory. Entire books dedicated to the subject often merely scratch the surface, and unless you’re a pro with all the expensive test gear needed to visualize what’s happening, the chances are pretty good that your antenna game is more practical than theoretical. Not that there’s anything wrong with that — hams and other RF enthusiasts have been getting by with antennas that work without really understanding why for generations.

But we’re living in the future, and the tools to properly analyze antenna designs are actually now within the means of almost everyone. [Andreas Spiess] recently reviewed one such instrument, the N1201SA vector impedance analyzer, available from the usual overseas sources for less than $150. [Andreas]’s review does not seem to be sponsored, so it seems like we’re getting his unvarnished opinion; spoiler alert, he loves it. And with good reason; while not a full vector network analyzer (VNA) that will blow a multi-thousand dollar hole in your wallet, this instrument looks like an incredible addition to your test suite. The tested unit works from 137 MHz to 2.4 GHz, so it covers the VHF and UHF ham bands as well as LoRa, WiFi, cell, ISM, and more. But of course, [Andreas] doesn’t just review the unit, he also gives us a healthy dose of theory in his approachable style.

[The guy with the Swiss accent] has been doing a lot of great work these days, covering everything from how not to forget your chores to reverse engineering an IoT Geiger counter. Check out his channel — almost everything he does is worth a watch.

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Super-Blue CNC Part Fixturing

March 29, 2018 by Brian McEvoy 20 Comments

Simple clamps are great if you need to keep the pressure on two parallel surfaces, but if you have an irregular plane, or you need to cut through it, clamps are not the correct tool. The folks at [NYC CNC] feature a video with a clever hack borrowing from other disciplines. Painters tape is applied to the top of a level mounting surface in the machine and then burnished. The same is done to the bottom of the workpiece. Superglue is drizzled between the tape layers and pressed together so now the stock is held firmly below the toolhead.

Some parts are machined in the video, which can be seen below, and the adhesion holds without any trouble. One of the examples they cut would be difficult to hold without damage or stopping the machine. The accepted wisdom is that superglue holds well to a slightly porous surface like tape, but it doesn’t like do as well with smooth surfaces like metal. Removing residue-free tape at the end of a cut is also cleaner and faster than glue any day.

If you have yet to cut your teeth, you can watch our very own Elliot Williams getting introduced to CNC machines or a portable machine even a child can use.

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3D Printed ESP8266 Programming Jig

March 27, 2018 by Tom Nardi 20 Comments

The various development boards such as the NodeMCU or Wemos D1 make working with the ESP8266 an absolute breeze. If they have a downside, it is that they are larger than the bare ESP2866, and of course cost a bit more. Just as with the Arduino, once you have the wiring sorted out and the code more or less finalized, your best bet is to ditch the unnecessary support hardware and use the bare module to save space and money in your final design.

The design took a few revisions to get right

Unfortunately, the ESP8266 form factor isn’t terribly forgiving when it comes time for hooking up a programmer. Rather than having to solder a serial adapter to the chip to flash it, [Ryan] came up with a slick 3D printed programming jig that uses pogo pins. If you have to program these boards in bulk, a jig like this can save a massive amount of time and aggravation.

Beyond the 3D printed holder for the pogo pins, this programmer uses a FTDI USB-to-serial adapter, a couple passive components to smooth out the power going into the chip, and a couple buttons.

In the video after the break, [Ryan] walks through the many iterations it took to get the 3D printed aspect of the jig worked out. The design went through a few rather large revisions, including one that fundamentally changed the whole form factor. Even with the jig now working, he mentions that he might circle back around and try it from a different angle.

Programming jigs are a staple of electronics manufacturing, and we’ve covered quite a few that have helped transformed a proof of concept into a small scale production runs.

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The Obscure Electronics Tools You Didn’t Know You Needed

March 26, 2018 by Lewin Day 76 Comments

The right tool for the job can turn a total headache into a 30-second operation. This is all the more important when you’re trying to streamline an assembly process, and the reason why you’ll find so many strange and wonderful purpose-built tools on any production line. With a nod to that old adage, [EvilMadScientist] have collected the tools you didn’t know you needed – until now.

If you’re wiring big through-hole boards all day, you’ve probably bemoaned the uneven bends on all your resistors. How did the big companies get it right way back when? They used a tool to set the distance of the resistor legs just right. What about DIP ICs? It’s a total pain trying to take them fresh out of the tube and get them to seat in a socket, but there’s a tool to do that too. It’s actually a two-part series, and while we’re sure you’ve all seen a solder sucker before, the fresh take on helping hands is pretty ingenious.

Overall, it’s a combination of little things that, with a bit of cash or a day’s work, you can have in your own lab and once you’ve got them, you won’t ever want to go back. Be sure to tell us about your favourite obscure tools in the comments.

Now that you’ve got your tools to hand, why not wrap them all up in a handy workstation?

A Resistor Cutting Robot You Can Build

March 26, 2018 by Lewin Day 13 Comments

If you’re populating kits, it can get tiring and time consuming. Like all good repetitive processes, it should be automated. As far as cutting resistors goes, this is one way to do it, thanks to [Pablo].

The build is actually cribbed from earlier work by a gang called [oomlout]. Parts for these cutters are made with either lasercut or CNC milled sheet stock. A stepper motor is used to transport the resistor tape, and the cutting blades are moved by standard hobby servos. The use of servos for the blades allows the action to be controlled precisely without having to go to the effort of implementing extra limit switches and circuitry.

Control is by an Arduino Uno, with an A4988 driver controlling the stepper. Servo control is achieved with the Uno’s onboard peripherals. There’s a video below of the machine in operation, which shows it to be a simple and efficient tool for the job.

This build turns an otherwise maddeningly basic chore into a set-and-forget operation. We’ve seen other work in this area before from the [oomlout] team, too. Video after the break.

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Drill Bit Gauge Is Interdenominational Black Magic

March 26, 2018 by Lewin Day 62 Comments

Oh, sure – when you buy a new set of drill bits from the store, they come in a handy holder that demarcates all the different sizes neatly. But after a few years when they’ve ended up scattered in the bottom of your toolbox for a while, it becomes useful to have some sort of gauge to measure them. [Caspar] has the solution, and all you need is an old steel rule.

The trick is to get a ruler with gradations for inches and tenths of inches. After cutting the ruler off just after the 6″ point, the two halves are glued together with some steel offcuts and epoxy. By assembling the two halves in a V shape with a 1 mm drill bit at the 1″ position, and a 5 mm drill bit at the 5″ marker, a linear slope is created that can be used to measure any drill bits and rod of the appropriate size inserted between the two.

It’s a handy tool to have around the shop when you’ve amassed a collection of bits over the years, and need to drill your holes accurately. Additionally, it’s more versatile than the usual method of inserting bits in appropriately sized holes, and can be more accurate.

Now that you’ve organised your drill bits, perhaps you’d like to sharpen them?

Handy Continuity Tester Packs Multiple Modes Into A Tiny Package

March 25, 2018 by Dan Maloney 10 Comments

From Leatherman multitools to oscilloscopes with built-in signal generators and protocol analyzers, there seems no end to tools with multiple personalities. Everybody loves multitaskers because they make it feel like you’re getting more bang for your buck, and in most cases that’s true. But a jack of all trades is seldom master of any, and there are times when even the humble multimeter isn’t the best tool for the job.

With that in mind, [sidsingh] has developed what we think is a very nice dedicated continuity tester. With a goal of using only parts on hand, he had to think small to fit everything into the case he had. So he started with a PIC10LF322 to support all the flavors of continuity testing he wanted to support. In addition to straight continuity, the tester can handle diode testing, detecting shorted or open diodes and even differentiating between regular and Schottky diodes. It also has an LED test mode and an interesting “discontinuity” testing mode — it only sounds its buzzer when continuity is broken. The video below shows that mode in action for finding intermittent cable faults, along with all the other modes.

For an ostensibly single-purpose tool, this tester still manages to pack a lot of tests into one very compact package. Simpler continuity testers are good, too — check out this cheap dollar store build, or this slightly more complicated unit based on an ATtiny85.

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