SMD Soldering on… Hot Sand?

smd soldering

Need to do some SMD soldering? No tools? No problem! Here’s a creative method that could be a handy tool to add to your belt: SMD soldering using hot sand.

[Oliver Krohn] recently released this little video demonstrating how to perform re-flow soldering using hot sand. He’s using a bunsen burner to heat up a ceramic pot of sand to use as a kind of hot plate. It seems to work pretty well, and it’s a very unique way of doing it — if you wanted to get a bit more technical, you could also throw a temperature probe in the sand to get a much finer heat control!

Of course there are lots of other ways of doing re-flow soldering, like using a re-purposed toaster oven, frying up some circuits on a skillet after you’ve had your bacon, or if you want to be fancy, you could even build your own toolkit for it!

Anyway, stick around for the epic video of SMD soldering on hot sand.

[Read more...]

This SMD Reflow Hot Air Gun Hangs Around Your Workbench

smd_reflow_hot_air_gun_nc_80

Has reflowing surface mount components got you down? [Giorgos] is currently working on a project that will lift your spirits…. well at least your hot air gun. Tired of manually holding his heat gun in one hand and IR thermometer in the other, [Giorgos] set out to create a device to alleviate just that. Although not completed yet, it appears the machine’s intent is to hold the heat gun at an appropriate height above the work piece in order to achieve the correct reflow temperature. He doesn’t say how the height of the hot air gun will be controlled. We’d like to see a microcontroller adjust the height of the hot air gun depending on the temperature of the component to be reflowed. [Giorgos] gives an extremely detailed account of his build process. Make sure to check out all four pages of the project post!

We’ve seen a lot of interesting work from [Giorgos] over the years like this capacitive touch-pad entry system.

[via Dangerous Prototypes]

Low-Power SMD Fireflies

lowpowerledfireflies

[Tyson's] family went with creating rather than buying Christmas presents last month, which gave him the opportunity to build some electronic fireflies for gifts. He drew inspiration from a similar firefly project we featured last year, but expanded on the original model by designing dedicated PCBs and housings for each of his firefly pieces.

Although he’d settled on using ATTiny85’s for this project, [Tyson] was fresh out of through-hole versions. He decided to skip the prototyping phase and go right for fabrication, cranking up the laser-jet printer for some toner-transfer, which successfully produced 4 functioning boards (and 3 failures). The fireflies were [Tyson's] first attempt at SMD soldering, and we’d have to say it’s a job well done; he reflowed each board with a cheap-o heatgun from Harbor Freight.

After some hiccups with fuse programming, [Tyson] got the code uploaded and the fireflies illuminated.  Swing by his site for the nuts and bolts on construction, then snag the project files here. (Direct .zip download)

Tiny 3x3x3 SMD LED Cube

led cube

LED cubes are cool, but they’re usually pretty big and clunky. [One49th] set out to make one of the smallest LED cubes we’ve seen yet, and he’s shared how he did it in his Instructable!

His first LED cube was the traditional kind, and it turned out pretty nice. But he wanted to go smaller — what about using SMD’s? What he did next was no simple feat — in fact, we’d be willing to call him an artist with a soldering iron. The array is just over one centimeter across.

Using a combination of vices and pliers he soldering each SMD onto his structure one by one. Each LED anode is tied together on each horizontal layer. Each cathode is tied together on each vertical column. This allows the TinyDuino to control any one LED by knowing which of the 9 columns and 3 layers the LED is on. Send a high signal to chosen layer, and a low signal to the column to light the LED. Doing this quickly allows you to create the illusion of different LEDs being on at the same time. Take a look through his image gallery to see just how tight the soldering quarters were, it’s definitely not something we’re planning on doing anytime soon!

Looking for a bigger cube? Check out this gorgeous 7x7x7 one that is capable of 142 frames per second!

Quick fixes for SMD population problems

quick-fixes-for-poor-PCB-work

Here’s a collection of tricks to get over some surface mount prototyping issues the next time you find yourself in a bind. But first we have to address the soldering atrocity seen on most of the components above. [Rxdtxd] admits he’s using a firestick for soldering his SMD parts. The non-brand 40W iron is just about the worst thing he could be using (well, we guess a candle would be worse). Try to overlook those joints and enjoy his solutions to a couple of other problems.

First up is what to do when you lift a fine-pitch trace like would be found on a TQFP footprint. The fix for this is to grab a junked transformer and use a bit of the enameled wire from the wrappings as a jumper. The wire is quite fine, and the insulation will burn off when soldered which means you don’t need to strip it first.

The second and third tricks both deal with resistors. As you can see above he placed two 1K resistors on a single resistor footprint to make his 2k resistor. The 0603 packages were both soldered standing on end, then connected with a lead from a through-hole component. The other resistor hack piles five components on top of each other to build resistance in parallel. This is not a great idea as it will fail over the long-term, but it will get you though the prototyping stage as long it doesn’t require precise tolerance.

Populate SMD boads using a toothpick and tweezers

cnlohr-hand-applied-solder-paste

Here’s a demonstration which proves you don’t really need special tools to populate a surface mount PCB. We’ve seen this board before, it’s the glass PCB server which [Cnlohr] developed and demonstrated by connecting the real world to Minecraft. It’s a tiny board and we were happy to have the chance to see his method for populating the parts before reflow soldering.

In the video after the break [Cnlohr] starts by dispensing a glob of solder pasted from its storage container. He mentions that as long as you store the stuff in the refrigerator it’s rather easy to work with. Because most of his projects are single boards it’s not worth it to have a solder stencil produced. Instead he picks up a bit of the solder glob on the end of a toothpick and applies it to each pad.

This isn’t really as bad as it sounds. The fine pitch TQFP footprints can just be dragged with a bit of the paste. After this application — which took around seven minutes — he grabs some tweezers (not the vacuum type) and begins placing each component. If he missed some paste he’ll discover it in this step and add where necessary. The last step is a trip through his toaster oven.

[Read more...]

DIY SMD stencils made with a craft cutter

stencil

Unless you’d like to spend hours with a toothpick and a tub of solder paste, stencils are the way to go whenever you’re placing SMD parts. While most commercial and industrial SMD stencils are made out of laser cut stainless steel, [Peter] figured out a piece of plastic and a $300 craft cutter is equally well suited for the job.

[Peter] has spent some time making SMD stencils out of polyester film in the form of overhead transparency sheets. This turned out to be a wonderful material; it’s dimensionally stable, commonly available, and just the right thickness suggested for SMD stencils. The polyester film was cut on a Silhouette Cameo, basically a desktop-sized vinyl cutter aimed at the craft market.

Stock, the Silhouette Cameo rounds off corners, not something [Peter] wanted with features only fractions of a millimeter. He came up with a tool to convert the paste layer of a Gerber file into separately drawn line segments, allowing him to cut SMD stencils for 0.3 mm pitch components.

It’s a great piece of work to make very fine pitch stencils, but we’re wondering if this tool could be used on the much less expensive Cricut paper and vinyl cutter that is unfortunately locked down with some very restrictive software.

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