Almost Fail of The Week: Doing Surface Mount Reflow Wrong In Every Possible Way and Still Succeeding

Sometimes the best way to learn is from the success of others. Sometimes failure is the best teacher. In this case we are learning from [Tim Trzepacz]’s successive failures in his attempt to solder one board to another using a reflow oven. They somehow cancelled each other out, and he ended up with a working board. For those of you who have used a reflow oven, there will be eye rolling.

[Tim]’s first mistake was to use regular solder instead of paste. We can see how he got there logically; if you hand solder an SMD you melt solder onto the pads first to make it easier. However, the result was that he had two boards that wouldn’t sit flat on each other thanks to the globs of solder on the pads.

Not to be deterred, he laid the boards on top of each other and warmed up the oven to a toasty 650 degrees. Well, not quite. The dang oven didn’t turn to eleven, so he figured 500 would probably work too. Missing the hint entirely, he let his board bake in a nearly 1000F oven until he noticed some smoke which, he intuitively knew, definitely shouldn’t be happening.

The board was blackening, the solder mask was literally bubbling off the substrate, people were coming over to see the show, and he decided success was still possible. He clamped the heated boards together with a binder clip until they cooled. Someone gave him a lesson on reflow, presumably listened to through reddening ears.

Ashamed and defeated, he went home. However, there was a question in his mind. Sure it looks bad, but is it possible that the board actually works? After a quick test, the answer was yes. It loaded some code and an time later he was happily hacking away. Go figure.

Technically A Hack. Still Questionable. Remote Control Food.

We thought we were going to read an article about, perhaps, a quadcopter that could fetch beer, or donuts. What we got was more along the lines of a donut dragging itself across the floor, rendering it pitiful and advisibly indigestible.

Sometimes people joke about not wanting to get in mind of a crazy person. We understand. While we could certainly follow [Michael Kohn]’s logic, the motivation was alien. Either way, in a rare turn of events there was not a single Arduino to be seen; just reverse engineering, unique solutions, and even a custom board. This is what some of you have been asking for… we think.

The brain of the questionable contraption is a TI MSP430G2231 and a tiny forward only motor driver circuit. The MSP waits for a signal from a hacked IR remote control from a cheap RC car. It then turns those into the appropriate motor control signals which go to some of those nice tiny metal gearboxes.

There were, naturally, a lot of technical issues in mounting the electronics to the food that, well… they didn’t need to be solved, but they were solved. For example, masking tape apparently does not stick well to green peppers, so toothpicks must be employed to pin the tape in place. Hopefully knowledge like this is scheduled for the nightly wipe while we sleep, but we’ll probably hold onto  it till we die, unlike expensive piano lessons.

In the end we had a good laugh, and the idea is so dumb it will probably be an educational Kickstarter next week. Video after the break.

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Stick Balances Itself With Reaction Wheels

The inverted pendulum is a pretty classic dynamics problem and reaction wheels are cool. That’s why we like [Mike Rouleau]’s self-balancing stick.

The video, viewable after the break, was fairly sparse on details, but he furnished some in the comments. The little black box on the top is a GY-521 Gyroscope module. It sends its data to an Arduino attached to the black cord which trails off the screen. The Arduino does its mathemagic and then uses a motor controller to drive the reaction wheels at the correct speeds.
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Drones, Clever Hacks, and CG Come Together For Star Wars Fan Film

We weren’t certain if this Star Wars fan film was out kind of thing until we saw the making of video afterwards. They wanted to film a traditional scene in a new way. The idea was to take some really good quadcopter pilots, give them some custom quadcopters, have them re-enact a battle in a scenic location, and then use some movie magic to bring it all together.

The quadcopters themselves are some of those high performance racing quadcopters with 4K video cameras attached. The kind of thing that has the power to weight ratio of a rocket ship. Despite what the video implies, they are unfortunately not TIE Fighter shaped. After a day of flying and a few long hikes to retrieve the expensive devices after inevitable crashes (which, fortunately, provided some nice footage), the next step was compositing.

However, how to trick the viewer into believing they were in a X-Wing quadcopter? A cheap way to do it would be to spend endless hours motion tracking and rendering a cockpit in place. It won’t look quite real. The solution they came up with is kind of dumb and kind-of brilliant. Mount a 3D printed cockpit on a 2×4 with a GoPro. Play the flight footage on a smartphone while holding the contraption. Try to move the cockpit in the same direction as the flight. We’re not certain if it was a requirement to also make whooshing and pew pew laser noises while doing so, but it couldn’t hurt.

In the end it all came together to make a goofy, yet convincingly good fan film. Nice work! Videos after the break.

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Lessons in Small Scale Manufacturing From The Othermill Shop Floor

Othermachine Co. is not a big company. Their flagship product, the Othermill, is made in small, careful batches. As we’ve seen with other small hardware companies, the manufacturing process can make or break the company. While we toured their factory in Berkeley California, a few interesting things stood out to us about their process which showed their manufacturing competence.

It’s not often that small companies share the secrets of their shop floor. Many of us have dreams of selling kits, so any lessons that can be learned from those who have come before is valuable. The goal of any manufacturing process optimization is to reduce cost while simultaneously maintaining or increasing quality. Despite what cynics would like to believe, this is often entirely possible and often embarrassingly easy to accomplish.

Lean manufacturing defines seven wastes that can be optimized out of a process.

  1. Overproduction: Simply, making more than you currently have demand for. This is a really common mistake for first time producers.
  2. Inventory: Storing more than you need to meet production or demand. Nearly every company I’ve worked for has this problem. There is an art to having just enough. Don’t buy one bulk order of 3,000 screws for six months, order 500 screws every month as needed.
  3. Waiting: Having significant delays between processes. These are things ranging from running out of USB cables to simply having to wait too long for something to arrive on a conveyor belt. Do everything you can to make sure the process is always flowing from one step to another.
  4. Motion: If you have a person walking back and forth between the ends of the factory to complete one step of the manufacturing process, this is wasted motion.
  5. Transport: Different from motion, this is waste in moving the products of each individual process between sections of the assembly.
  6. Rework: Get it right the first time. If your process can’t produce a product that meets specifications, fix the process.
  7. Over-processing: Don’t do more work than is necessary. If your part specifies 1000 hours of runtime don’t buy a million dollar machine to get 2000 hours out of it. If you can find a way to do it with one step, don’t do it with three.

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The first thing that stuck out to me upon entering Othermachine Co’s shop floor is their meticulous system for getting small batches through the factory in a timely manner. This allows them to scale their production as their demand fluctuates. CNCs and 3D printers are definitely seasonal purchases; with sales often increasing in the winter months when hackers are no longer lured away from their workstations by nice weather.

As the seven sins proclaim. It would be a bad move for Othermachine Co. to make too many mills. Let’s say they had made an extra 100 mills while demand was at a seasonal low. If they found a design or quality problem from customer feedback they’d have to commit to rework, potentially throwing away piles of defective parts. If they want to push a change to the machine or release a new model they’d either have to rework the machines, trash them, or wait till they all sold before improving their product. Even worse, they may find themselves twiddling their thumbs waiting for their supply to decrease enough to start manufacturing again. This deprives them of opportunities to improve their process and leads to a lax work environment.

One way to ensure that parts are properly handled and inventory is kept to a minimum is with proper visual controls. To this end, Othermachine Co has custom cardboard bins made that perfectly cradle all the precision parts for each process in their own color coded container. Since the shop floor is quite small, it lets them focus on making spindle assemblies one day and motion assemblies another without having to waste time between each step. Also, someone can rekit the parts for a recently completed step easily without interrupting work on the current process going on.

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It’s hard to define what’s over processing and what isn’t. My favorite example of what isnt, and something I’ve fought for on nearly every factory floor I’ve worked on is proper torque limiting screwdrivers. They’re a little expensive, but they are a wonderful tool that helps to avoid costly rework and over processing. For example, let’s say you didn’t have a torque limiting screwdriver. Maybe your customers would complain that occasionally a screw came loose. Now, one way to solve this would be the liberal application of Loctite. Another way would be an additional inspection step. Both of these are additional and completely uneccessary steps as most screws will hold as long as they are torqued properly.

In one factory I worked in, it was often a problem that a recently hired worker would overtorque a screw, either stripping it or damaging the parts it was mating together. A torque limiting screwdriver takes the worker’s physical strength out of the equation, while reducing their fatigue throughout the day. It’s a win/win. Any time a crucial step can go from unknown to trusted with the application of a proper tool or test step it is worth it.

Another section where Othermachine Co. applied this principle is with the final machining step for the CNC bed. The step produces a large amount of waste chips. Rather than having an employee waste time vacuuming out every Othermill after it has gone through this process, they spent some time designing a custom vacuum attachment. This essentially removed an entire production step. Not bad!

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With the proper management of waste it is entirely possible to save money and improve a process at the same time. It takes a bit of training to learn how to see it. It helps to have an experienced person around in order to learn how to properly respond to them, but with a bit of practice it becomes a skill that spreads to all areas of life. Have any of you had experience with this kind of problem solving? I’ve really enjoyed learning from the work stories posted in the comments.

Star Track: A Lesson in Positional Astronomy With Lasers

[gocivici] threatened us with a tutorial on positional astronomy when we started reading his tutorial on a Arduino Powered Star Pointer and he delivered. We’d pick him to help us take the One Ring to Mordor; we’d never get lost and his threat-delivery-rate makes him less likely to pull a Boromir.

As we mentioned he starts off with a really succinct and well written tutorial on celestial coordinates that antiquity would have killed to have. If we were writing a bit of code to do our own positional astronomy system, this is the tab we’d have open. Incidentally, that’s exactly what he encourages those who have followed the tutorial to do.

The star pointer itself is a high powered green laser pointer (battery powered), 3D printed parts, and an amalgam of fourteen dollars of Chinese tech cruft. The project uses two Arduino clones to process serial commands and manage two 28byj-48 stepper motors. The 2nd Arduino clone was purely to supplement the digital pins of the first; we paused a bit at that, but then we realized that import arduinos have gotten so cheap they probably are more affordable than an I2C breakout board or stepper driver these days. The body was designed with a mixture of Tinkercad and something we’d not heard of, OpenJsCAD.

Once it’s all assembled and tested the only thing left to do is go outside with your contraption. After making sure that you’ve followed all the local regulations for not pointing lasers at airplanes, point the laser at the north star. After that you can plug in any star coordinate and the laser will swing towards it and track its location in the sky. Pretty cool.

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Unexpected Betrayal From Your Right Hand Mouse

Some people really enjoy the kind of computer mouse that would not be entirely out of place in a F-16 cockpit. The kind of mouse that can launch a browser with the gentle shifting of one of its thirty-eight buttons ever so slightly to the left and open their garage door with a shifting to the right of that same button. However, can this power be used for evil, and not just frustrating guest users of their computer?

We’ve heard of the trusted peripheral being repurposed for nefarious uses before. Sometimes they’ve even been modified for more benign purposes. All of these have a common trend. The mouse itself must be physically modified to add the vulnerability or feature. However, the advanced mice with macro support can be used as is for a vulnerability.

The example in this case is a Logitech G-series gaming mouse. The mouse has the ability to store multiple personal settings in its memory. That way someone could take the mouse to multiple computers and still have all their settings available. [Stefan Keisse] discovered that the 100 command limit on the macros for each button are more than enough to get a full reverse shell on the target computer.

Considering how frustratingly easy it can be to accidentally press an auxiliary button on these mice, all an attacker would need to do is wait after delivering the sabotaged mouse. Video of the exploit after the break.

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