DIY Solder Stencils From Soda Cans

February 4, 2013 by Brian Benchoff 29 Comments

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Even if you’ve overcome your fear diddling about with tiny SMD components, applying solder paste – especially if you’re populating more than one board at a time – is still a chore. The pros use very expensive laser cut stainless steel solder paste stencils, something still a bit out of reach to the casual hobbyist. [Felix] solved this problem by making his own solder paste stencils very cheaply using empty soda cans.

The process begins just like any other home etching tutorial by lightly sanding the un-bent aluminum can and applying the etch resist via the toner transfer method. Etching is done with off-the-shelf HCl and hydrogen peroxide, resulting in an amazingly clean stencil comparable in quality with a professional stencil.

Sure, going through a dozen-step process to make a solder paste stencil may not be as convienent as [Cnlohr]’s toothpick and tweezers method, but [Felix]’ method is just about up to par with extraordinarily expensive laser cut stainless steel stencils. Not bad for something that came from the recycling bin.

Ammo Box PSU

February 3, 2013 by Brian Benchoff 30 Comments

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Sometimes you need a power supply that can be thrown into the back of a car and taken into the field. [BadWolf] didn’t want to take his bench supply, so he whipped up this very portable power supply made from a computer PSU. To ruggedize his build a little, he put it in a 50 caliber ammo can making it more than able to handle the roughest field work.

While not a proper adjustable power supply, this ammo can is more than capable of delivering a whole lot of current in a number of different voltages. There are a few bells and whistles – a ‘plugged in’ and ‘on’ light, as well as a few very cool looking toggle switches that are sure to arouse the suspicions of unsuspecting bystanders.

[BadWolf] kept all the safety features built-in to the computer PSU, so this ammo box power supply is still protected from short circuits, and over-current, making it much safer than its appearance belies. It’s also a great example of what can be done if you don’t have a proper bench supply, so we’ve got to tip our hat to [BadWolf] for that.

Reverse Engineering Salvaged Part Footprints

February 1, 2013 by Mike Szczys 35 Comments

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So you just pulled a fancy component off of a board from some broken electronics and you want to use it in your own project. What if the data sheet you found for it doesn’t include measurements for the footprint? Sure, you could pull out your digital calipers, but look at the measurements in the image above. How the heck are you supposed to accurately measure that? [Steve] found an easy answer for this problem. He uses microscope software to process an image of the board.

One common task when working with a microscope is measuring the items which are being viewed under magnification. [Steve] harnessed the power of a piece of free software called MiCam. One of its features is the ability to select an area of the photograph so serve as the measuring stick. To get the labels seen in the image above he selected the left and right edges of the board as the legend. He used his digital calipers to get a precise measurement of this area, then let the software automatically calculate the rest of the distances which he selected with his cursor.

MiCam is written for Windows machines. If you know of Linux or OSX alternatives please let us know in the comments.

Turning The Stellaris Launchpad Into A Logic Analyzer

January 27, 2013 by Brian Benchoff 20 Comments

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If you have a Stellaris Launchpad sitting around, have a go at using it as a logic analyzer

The Stellaris logic analyzer is based upon this earlier build that took code from a SUMP comparable Arduino logic analyzer and ported it to the much faster and more capable Stellaris Launchpad with an ARM Cortex 4F processor.

This build turns the Launchpad into a 10 MHz, 8-channel logic analyzer with a 16 kB buffer comparable with just about every piece of software thanks to the SUMP protocol. Even though the ARM chip in the Launchpad isn’t 5 Volt tolerant, only pins 0 and 1 on Port B are limited to 3.6 Volts. All the other pins on Port B are 5 Volt tolerant.

Not a bad piece of work to turn a Launchpad that has been sitting on your workbench into a useful tool.

$20 Vacuum Pen Build On Of The Best We’ve Seen

January 25, 2013 by Mike Szczys 9 Comments

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Everything you need to build a vacuum tweezers is laid out in this image. The parts should run you about $20 and when you’re done you’ll have the perfect tool for placing very small surface mount parts for reflow soldering.

This project uses the same concept as other fish pump tweezers projects but builds upon them with some interesting additions. The first step in the conversion process is to tear down the aquarium pump to reverse its flow. There are several steps but all-in-all it’s not very difficult. With the source of vacuum established [Technically Artistic] begins work on the business end of the tool. This is where the array of different pens see some action. The large blue one is the outer assembly, with the others combining to help connect it to the plastic tubing. The business end is made from a needle adapter for an air compressor, with an alligator clip cleverly modified to serve as a valve to release the parts from the tip.

Fitting A Cold, Metal Heart In An Altoids Tin

January 24, 2013 by Brian Benchoff 18 Comments

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[James] has been building a heart rate monitor using a very cool TI chip. He needed a way to test his device, and commercial ECG simulators, like all biotech devices, are absurdly expensive. [James] decided to build his own heart rate simulator, and in the process made a great tool and one of the most well documented projects we’ve ever seen.

Of course, if you’re building an ECG simulator, you’re going to need a good sample of a heart’s electrical pattern. To get this sample, [James] found an old army manual with a diagram of an ideal ECG pattern. [James] took this PDF manual, screen capped the diagram, and used a Python script to generate an array in C the Arduino could repeat over and over.

The rest of the build consisted of a D/A converter, a pot to change the heart rate, a very nice seven-segment display, and a few banana jacks to connect to [James]’ heart monitor. Everything is up in a git, including an amazingly well documented (87 pages!) tutorial for building your own Arduino heart simulator.

Laser Cut PCBs

January 22, 2013 by Brian Benchoff 45 Comments

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Despite what you may have heard, those 40 Watt laser cutters actually can cut out traces on your next PCB.

Since he got his laser cutter a year and a half ago, [Rich] over at Nothing Labs has been trying to cut PCBs with it. Others have tried, usually by masking off a piece of copper followed by chemical etching. [Rich] wanted a one-step process, though, and his laser cutter really isn’t up to the task of cutting metal.

All that changed when he heard of another maker cutting .001″ thick stainless steel on a similar laser cutter. Stainless steel isn’t solderable, but mild steel is. After finding a very thin piece of mild steel, [Rich] taped it down to a sheet of acrylic, designed a simple 555 blinky LED circuit, and tried out a new technique.

It turns out it is possible to cut very thin steel into circuit traces, and with enough flux to turn them into a functional circuit. As a bonus the resulting circuit looks really cool and a board can be made in mere minutes.

It’s not the thing for very fine work – the minimum trace width [Rich] can get is about 1/16″, but it is a very fast way to prototype a few circuits.

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