Hackaday Links: January 12, 2014

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[Kyle] teaches photography and after being dismayed at the shuttering of film and darkroom programs at schools the world over decided to create a resource for film photography. There’s a lot of cool stuff on here like mixing up a batch of Rodinal developer with Tylenol, lye, and sodium sulphite, and assessing flea market film cameras. There are more tutorials coming that will include setting up a dark room, developing prints, and playing around with large format cameras.

[hifatpeople] built a binary calculator out of LEGO® bricks or toys. It started off as a series of logic gates built out of LEGO® bricks or toys in the LEGO® Digital Designer. These logic gates were combined into half adders, the half adders combined into full adders, and the full adders combined into a huge plastic calculator. Unfortunately, buying the LEGO® bricks or toys necessary to turn this digital design into a physical model would cost about $1000 using the LEGO® Pick-A-Brick service. Does anyone have a ton of LEGO® Technic® bricks or toys sitting around? We’d love to see this built.

Think you need a PID controller and fancy electronics to do reflow soldering in a toaster oven? Not so, it seems. [Sivan] is just using a meter with a thermocouple, a kitchen timer, and a little bit of patience to reflow solder very easily.

The folks at DreamSourceLabs realized a lot of electronic test equipment – from oscilloscopes and logic analyzers to protocol and RF analyzers were all included a sampling circuit. They designed the DSLogic that puts a sampler and USB plug on one board, with a whole bunch of different tools connected to a pin header. It’s a pretty cool idea for a modular approach to test equipment.

Adafruit just released an iDevice game. It’s a resistor color code game and much more educational than Candy Crush. With a $0.99 coupon for the Adafruit store, it’s effectively free if you’re buying anything at Adafruit anytime soon. Check out the video and the awesome adorable component “muppets”.

A Pair Of Toaster Reflow Oven Builds

For some reason or another, the Hackaday tip line sometimes sees a short burst of submissions for the same project. The latest one of these was for toaster oven reflow stations. They’re both great builds and different approaches to making a useful tool out of home appliances.

First up is [Richard]’s build. he ended up with a fairly high-end build using a Rocket Scream Reflow Oven Controller Arduino shield. This shield accepts a normal K-type thermocouple and controls an external solid state relay with the Arduino’s PID library. [Richard]’s build has a few neat additions – a properly dremeled enclosure, computer fan, and a welding blanket for insulation. Now that we think about it, it’s odd we’ve rarely seen any sort of insulation in these reflow oven builds.

Next up is [Ray]’s version of a Black & Decker reflow oven. While not as fancy as [Richard]’s build, this one does have a few features that make it very interesting. Instead of messing around with thermocouples, [Ray] simply took a digital kitchen thermometer – a neat tool that already a thermistor in a compact metal probe – and read the analog value with an Arduino. To control the power, [Ray] is using a cheap 433 MHz radio transmitter to control a few remotely operated power sockets. It’s a very clever and inexpensive replacement for a SSR, especially since [Ray] had these power sockets just lying around.

So there you go. The same tool, built two different ways. A great demonstration of how you can not only build anything, but you can build anything any way you want.

Reflow Oven Courtesy Of Hurricane Sandy

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The Makerbar, Hoboken’s Hackerspace, was in desperate need of a reflow oven. Hurricane Sandy did a number on a whole bunch of household appliances, so when [Kush] saw a neighbor throw out a broken toaster oven, the Makerbar crew sprung into action.

The storm waters shorted the electronics board, fried the existing controls, and basically turned the oven into a metal shell with heating elements. It was the perfect platform for a toaster oven – every part that was going to be thrown out was already destroyed.

[Zach] over at the Makerbar ordered the Sparkfun reflow toaster conversion kit along with a few arcade buttons and set to work. After plugging the heating elements into the mains power to make sure they still worked, [Zach] attached these elements to the relay on board the controller. Three arcade buttons were wired up to the controller, and a whole bunch of code was written.

With the included thermocouple, [Zach], [Kush], and the rest of the Makerbar gang now have a very accurate and reliable reflow oven. There’s also settings for Sculpey clay and shrinky dinks, just in case anyone at Makerbar is feeling a bit creative.

Fine-pitch SMD Soldering With Minimal Tools

We try to stick to the 0805 parts because they’re still big enough to solder by hand. But [Scott] shows us that it doesn’t take too many special tools to reflow fine-pitch components at home. In this case he’s using 0402 resistors, a footprint that we consider functionally impossible to solder using an iron.

The two parts of the equation that he spent some money on are professionally produced PCBs and a solder stencil. The stencil is laser-cut from Kapton, which is heat-resistant so it doesn’t warp during the cutting process. An acrylic frame holds the PCB in place, and he just tapes the stencil over it and uses a chunk of acrylic as a squeegee to evenly apply the solder paste. Splurging on the PCB and stencil means you’ll achieve tolerances which lead to success.

The next issue is placing the components. [Scott] shows off some vacuum tweezers he built using an aquarium pump. Watch the video after the break to see how small those 0402 parts are when he extracts one of the resistors from the tape packaging. With the board manually populated (check everything twice!) he moves the board to a completely unaltered toaster oven for reflow. We have seen a lot of projects which add controllers to these ovens, but he really makes the case that you don’t need it. Instead, he uses a thermocoupler read by a multimeter just to let him know what’s going on with the temperature. He uses a smart phone as a timer, and switches the oven on and off to match the solder’s heat profile. Continue reading “Fine-pitch SMD Soldering With Minimal Tools”

Toaster Oven Reflow Soldering Roundup

SMD components have a lot of advantages over the through-hole parts our fathers and grandfathers soldered. Working with these tiny surface mount components requires a larger investment than a soldering iron and a wire-wrap gun, though. Here’s a few reflow ovens that were sent in over the past week or two.

[ramsay] bought a 110 V toaster oven off of eBay. Even though [ramsay] is in England and has 230 V mains, everything in the oven is mechanical and works just fine with a higher voltage. His first test didn’t go quite as planned; the solder paste wasn’t melting at 120° C, so he cranked up the temperature and learned that the FR in FR-4 stands for flame retardant. Never deterred, [ramsay] decided to build a controller so the temperature ramps up and cools off at the right rates for the flux and paste to do their thing.

Solder paste has a temperature profile that requires the board to be kept at a temperature between 150° and 180° C for a minute or so before climbing up to 220° for a second so the solder will melt. [Nicolas] had the interesting idea of putting a USB port in his toaster oven and storing the heating profiles on his desktop. The build uses an MSP430 microcontroller to turn the relays powering heating elements on and off. [Nick] is working on a C# desktop app to monitor and regulate the oven temperature from his computer, so we’re fairly interested in seeing the final results.

Watching the SMD self-alignment videos on YouTube is a lot more fun than messing around with tweezers, stereo microscopes, and extremely fine soldering irons. If you’ve got a better idea for a toaster/reflow oven, send it in on our tip line and we’ll check it out.

A USB-controlled Solder Reflow Oven

[Joel] of [Helion Microsystems] is at it again with his USB controlled solder reflow oven.  You may remember him from his crazy twitter-enabled Ewok model. Although these two projects are quite different, they both use the HU-320 USB breakout board that he’s in the process of getting funding for via [Pozible], or Australian Kickstarter for Yanks.

The reflow oven works using a thermocouple-enabled RS-232 voltmeter to output the temperature to the HU-320 board. [Joel] has been nice enough to provide us with the C# code to interface with many multimeters if you want to implement a similar project.  Temperature is controlled with a mechanical relay for what would appear to be a poor man’s PID controller.

Sadly, Fluke meters don’t seem to be listed, but your place of work probably wants their meter back anyway!  For another toaster reflow oven implementation, check out this [HAD] article.  Be sure to check out the video after the break for a video of the setup! (heat treat engineers may find the “recipe” format humorous).

Continue reading “A USB-controlled Solder Reflow Oven”

Toaster Oven Reflow Control Without Modifying The Oven

[Eberhard] wanted his own reflow oven but didn’t really want to mess around with the internals that control the heating element. He put his microcontroller programming experience to work and came up with an add-on module that controls the oven by switching the mains power.

The image above shows a board in the midst of the reflow process. If you’re not familiar, solder paste usually comes with a recommended heat curve for properly melting the slurry. [Eberhard] managed to fit three of these temperature profiles into his firmware.

The ATtiny45 which makes up the controller samples oven temperature via the thermistor seen next to the board. A PID algorithm is used to calculate when to switch mains power on and off via a relay. One button and one LED make up the controller’s user interface for scrolling through the three preprogrammed temperature profiles.

It looks like it works great, see for yourself in the clip after the break.

Continue reading “Toaster Oven Reflow Control Without Modifying The Oven”