Fast And Easy Solder Paste Stencils

June 18, 2012 by Brian Benchoff 12 Comments

If you’re making your own boards with SMD parts, you might want to get a solder paste stencil. Usually made of laser-cut mylar or extremely thin steel, these stencils allow you to squeegee solder paste onto your board’s pads and make assembly a whole lot easier. [Rochey] needed a stencil for a board he was working on, and lacking a laser cutter he turned to what he had available – a few bits of plastic and a CNC machine.

[Rochey] began making his stencils out of laminating pouches and an xacto knife. This worked well, but it was time-consuming, and a bit fiddly when cutting 1 mm square holes. To speed up the process, [Rochey] put one of these laminating pouches on his CNC machine, exported the ‘Top Cream’ layer in Eagle to the CNC software of his choice, and had his machine attack the plastic with a 1 mm drill bit.

To [Rochey]’s surprise, everything went as planned; in five minutes, he had a stencil with perfectly accurate holes that masked off everything but the SMD pads.

Thanks [Fabien] for sending this one in.

BattMan II: The Charger Your Batteries Deserve

June 17, 2012 by Caleb Kraft 13 Comments

When your radio controlled device batteries are drained, you’ve got no better option than to call on BattMan II. This device is packed full of features for cycling and charging various types of batteries. It is computer controlled via your parallel port (yeah, remember those?) and has companion software that allows you all kinds of control and data.

The writeup is rather extensive and includes schematics so you could build your own. There’s also a step by step breakdown of how each section functions as well as an explanation of each different charging method. Great work [Stefan]

if you just want a peak at the lengthy feature list, keep reading.

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Multimeter Add-on Lets You Measure Tiny Resistance Values

June 15, 2012 by Mike Szczys 15 Comments

This multimeter add-on is called the Half Ohm. It allows you to measure small resistance values, and can be used to track down shorts on a PCB.

The board acts as a pass-through for both probes. When your meter is set to measure voltage and nothing is connected to the probes the display will read out the level of the coin cell that powers the add-on. When you are probing, the value in millivolts is actually showing the resistance in milliohms. This works for any measurement less than one Ohm. Interestingly enough, it will help you zero in on a solder bridge. By probing the two shorted tracks you can find the issue by following the falling resistance values.

[Jaanus] published several posts leading up to the final version of the board. Check out this category link for his blog if you’re interested in reading through them.

Making Giant Wooden Balls

June 13, 2012 by Brian Benchoff 37 Comments

One day, we hope, we’ll be as awesome as [Keith Holaman]. He makes humongous wooden balls with a chainsaw, crane, and a truck-mounted lathe.

[Keith] got his start making wooden balls on a small lathe at home. For some reason he always wanted to make a bigger wooden ball, but his equipment at the time couldn’t handle this size in [Keith]’s imagination.

To make his gigantic wooden balls, [Keith] skulks around his local forest looking for downed trees and stumps. After getting these huge logs home, he roughs out the sphere with a chainsaw, mounts a chuck on the log with huge bolts, and attached it to a diesel motor.

Because the logs are so huge, he can’t turn the log very fast. to remove a whole lot of wood very quickly, [Keith] spins his tool head at a few thousand RPM.

There aren’t many build details or even an indication of how big these wooden balls are. We’d guess they’re easily over a meter in diameter. If anyone knows where we can see these balls in person, drop a note in the comments.

Building A Foundry In Your Backyard

June 12, 2012 by Brian Benchoff 25 Comments

[th3BadWolf] has been wanting to build a foundry for some time now. Done right, it’s a very neat tool; it’s fairly easy to do aluminum castings, and if you’re clever enough a foundry can lead to building large machine tools such as a lathe or a mill. Anything worth doing is worth overdoing, so [BadWolf] is designing his foundry to melt 150 pounds of aluminum every 45 minutes.

The build began with a humble oil barrel. [th3BadWolf] cut the top off of the barrel and began lining the inside of the barrel with a ceramic blanket and refractory bricks. To hold this somewhat precarious assemblage of blanket and brick together, [BadWolf] is holding everything together with 3000° F cement.

The body of the furnace is nearly complete, but [BadWolf] still has to drill a few holes for the burner system. He’s going to start each burn with Propane, then move over to engine oil when the furnace gets hot enough. Truly an awesome project, and we can’t wait to see the results.

Talking Resistor Calculator Speaks Component Values

June 11, 2012 by Brian Benchoff 21 Comments

If there’s one thing that will surely blind us, its reading resistor color bands. It doesn’t help that red looks exactly like orange, brown and black are indistinguishable, and different component manufacturers – for some reason – don’t use identical paints for coding their resistors. [Jeff] over at Gadget Gangster has been having the same problem, so he built a talking resistor calculator to speak resistor values to him.

The electronics part of the build is extremely simple with just an MCP3208 ADC providing 12 bits of resolution. The software side is where this project really shines. [Jeff] used a Gadget Gangster QuickStart board housing a Parallax Propeller. With 8 cores running in parallel the Propeller is more than enough to run [Phil Pilgrim]’s software speech synthesizer. When a resistor is connected to the two alligator leads, the Propeller goes through a lookup table and finds a resistor value matching the number coming from the ADC. From there, it’s just sending a string of phonetic text to the speech synthesizer object.

Even though text-to-speech chips have been around for decades now, [Jeff] chose to build his speech synthesis tool with software. It may just be a testament to the power in the Propeller microcontroller, but anything that keeps us from squinting at resistor color bands is alright by us.

Book Scanner Kits Now Available

June 4, 2012 by Caleb Kraft 28 Comments

[Daniel Reetz] wants you to be able to scan books. This has been a goal of his for quite some time, and now he’s bringing a kit into play. We’ve always liked book scanners here, many of us have extensive libraries or even peculiar selections we would like to share. [Daniel] is starting off with a short run of these scanners. Once all the bugs are worked out, there should be plenty available for everyone. The kit includes the frame, LED lighting, bicycle levers, and cables. You have to add glass, books, and a camera.

Of course, if you still want to design and build your own, there are TONS of variations available in the forums at DIYbookscanner.org.

[via Adafruit]

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