The Bootup Guide To Homebrew Two-Stage Tentacle Mechanisms

September 13, 2016 by Sonya Vasquez 42 Comments

What’s not to love about animatronics? Just peel back any puppet’s silicone skin to uncover a cluster of mechatronic wizardry that gives it a life on the big screen. I’ve been hunting online for a good intro to these beasts, but I’ve only turned up one detailed resource–albeit a pretty good one–from the Stan Winston Tutorials series. Only 30 seconds into the intro video, I could feel those tentacles waking up my lowest and most gutteral urge to create physical things. Like it or not, I was hooked; I just had to build one… or a few. This is how you built a very real animatronic tentacle.

29172101050_b8d50d333e_z — I built this. And you can too!

If you’re getting started in this realm, I’ll be honest: the Stan Winston Tutorial is actually a great place to start. In about two hours, instructor Richard Landon covers the mindset, the set of go-to components, and the techniques for fabricating a tentacle mechanism with a set of garage tools–not to mention giving us tons of real-film examples along the way [1].

We also get a sneak peek into how we might build more complicated devices from the same basic techniques. I’d like to pick up exactly where he left off: 4-way two-stage tentacles. And, of course, if you’ve picked up on just how much I like a certain laser-cuttable plastic at this point, I’m going to put a modern twist on Landon’s design. These design tweaks should enable you to build your own tentacle and controller with nothing more but a few off-the-shelf parts, some Delrin, and a laser cutter… Ok, fine, a couple 3D printed parts managed to creep their way in too.

In a good-ol’ engineers-for-engineers fashion, I’m doing something a little different for this post: I’m finishing off this series with a set of assembly videos, a BOM, and the original CAD files to make that beast on the front page come to life. As for why, I figured: why not? Even though these mechanisms have lived in the robotics community and film industry for years, they’re still lacking the treatment of a solid, open design. This is my first shot at closing that gap. Get yourself a cup of coffee. I’m about to give you every bleeding detail on the-how-and-why behind these beasts.

All right; let’s get started.

Continue reading “The Bootup Guide To Homebrew Two-Stage Tentacle Mechanisms” →

Take Your PCBs From Good To Great: Toner Transfer

September 12, 2016 by Elliot Williams 98 Comments

dscf8697 — One-offs that I never would have gotten professionally made, but that were infinitely handy during development

A lot of us make circuit boards at home. I find it a useful skill to have in my bag of tricks for intermediate steps along the way to a finished project, even if the finished version is going to be sent out to a PCB fab. When I need a breakout board that meshes with other development tools, for instance, there’s nothing like being able to whip something up that plugs right in. Doing it quickly, and getting on with the rest of the project instead of placing an order and waiting for delivery, helps keep me in the flow.

Toner transfer is by far the fastest way to make a circuit board at home — simply print the circuit out on a laser printer, iron it onto the copper, and etch. When it works, it’s awesome. When it doesn’t, it can be a hair-pulling exercise in figuring out which of myriad factors are misaligned.

For a long time now, I’ve been using a method that’s very reliable and repeatable. Recently, I’ve been tweaking a bit on the performance of the system, and I thought I’d share what I’ve got. At the moment, I’m able to very reliably produce boards with 6 mil (0.15 mm) traces and 8 mil (0.20 mm) spacing. With a little care in post-production, 4 mil / 6 mil is entirely plausible.

Continue reading “Take Your PCBs From Good To Great: Toner Transfer” →

Path To Craftsmanship: The Art Of Being Wrong

September 12, 2016 by Gerrit Coetzee 43 Comments

Every technical person knows, unlike artists and politicians, that they can be provably wrong; at least to a degree. Math tells the truth. Coupled with this knowledge is an ego which is often entirely based on our output. If our mechanism works, we feel good because we are provably good.

A disclaimer. — It didn’t stop Scott Adams from writing four books full of it and it won’t stop me.
from Dilbert: *Advice*

Unfortunately, unlike the robots we build or the simple minds we spin out of code, we are still human at the end of the day. When we feel the sting of being wrong we often respond poorly. Some of us slip into depression, claiming it all and dredging up a few other mistakes from our past along for the ride. Some of us explode into prideful rages, dropping our metaphorical shorts to show that this one fault is no fault at all compared to a history of personal majesty. Others become sullen and inward. Others ignore it all together. Others yet strike out at those around them leaving unpleasant barbs. The variations are endless, but I do think there is an ideal to be reached.

Despite the risk that the nature of the things I’ve learned will reveal exactly what kind of arrogant sod I am, I’ll give it a go anyway. I’ve made many mistakes, and I have many more to make, but these are some of the things I’ve learned. I’ve learned them all in technical fields, so I’m not sure how broadly the advice applies, but luckily this is Hackaday.

Continue reading “Path To Craftsmanship: The Art Of Being Wrong” →

VW Engineer Pleads Guilty To Conspiracy

September 9, 2016 by Mike Szczys 173 Comments

[James Liang], an engineer at Volkswagen for 33 years, plead guilty today to conspiracy. He was an engineer involved in delivering Diesel vehicles to market which could detect an emissions test scenario and perform differently from normal operation in order to pass US emission standards.

A year ago we talked about the Ethics in Engineering surrounding this issue. At the time we wondered why any engineer would go along with a plan to defraud customers. We may get an answer to this after all. [Mr. Liang] will cooperate with authorities as the VW probe continues.

According to information in the indictment, none of this happened by mistake (as we suspected). There was a team responsible for developing a mode that would detect a test and pass inspection after the company discovered the engine could not otherwise pass. It’s not hard to see the motivation behind this — think of the sunk cost in developing an engine design. The team responsible for cheating the tests went so far as to push software updates in 2014 which made the cheat better, and lying about the existence of these software “features” when questioned by authorities (again, according to the indictment).

Life On Contract: Estimating Project Time

September 9, 2016 by Gerrit Coetzee 51 Comments

You sit there, irritation bubbling deep within as minute forty-five of the meeting ticks past on the clock in the corner of the office. Fight or flight is in a contest with your attention span as you struggle to keep an interested look on your face while they drone on. Real work could be done in this time. Maybe if you go to the bathroom you could sort of… fast forward the meeting. Panicked thinking continues for a bit until your awareness snaps back to the babble of words in the room.

“How long will it take you to do this?” the manager asks.

“A couple of days maybe?” You reply in turn. The manager nods and you take your escape. Little do you know that you have failed.

The project swerves out of control. Two days on the dot the manager is there expecting results. How? How did this happen again? It felt right! Two days is all you’d need to do such a simple project. It ended up taking a week.

The next meeting you say two weeks just to be sure. Everyone nods gravely, upset that something would take so long, but the work must be done. Two days later you sheepishly wander into the manager’s office with a completed project. He looks pleased but confused. The next meeting, he insists that you can do it in half the time. You and your fragile pride bowl ahead only to deliver late. The mystery!

This was my life until I started bugging the more experienced around me. I learned a lot from them and I ended up distilling it down into a few rules.

There Is No Other Unit Than Hours
Be honest.
Get Granular.
Promise a Range. Give a Deadline.

Why?

Why does someone want a time estimate? What are they going to do with this information? When working on a contract job it often feels like sticking a foot in a trap when a time estimate is given. Are they going to hold me to this? What if it goes wrong? After all, we are not fortune tellers. Unless the manager is extremely bad or you show yourself to be extremely lax in your duties, it is unlikely that a time estimate will be used against you.

Continue reading “Life On Contract: Estimating Project Time” →

Megasquirting My 1983 Datsun Z

September 8, 2016 by Bil Herd 97 Comments

When Dinosaurs Drove to Work

Back in the mid 1980’s I worked at a company called Commodore Business Machines, a company that made home computers where our annual Superbowl was the Consumer Electronics Show in Las Vegas the first week in January.

Some time in November a Datsun Z would get parked in the front lot and then not move until whatever snow mounds that got plowed over it melted sometime in early spring. Ultimately I would have it towed leaving behind a sad little pile of rust and nuts and bolts. With a bonus check in hand for finishing the newest computer on time I would go buy another used Z and repeat the cycle.

Climate Change and Rust

These days the old Datsun Z’s; 240Z, 260Z, 280Z, 280ZX, are somewhat rare, probably because they were real rust buckets even when new. After having sacrificed a few myself in search of the next home computer I set out to rescue one for old times’ sake. I really did love the car so I made it my project to restore one. Now I have a total of three Z carcasses, an engine, and a transmission all sitting out back and an almost finished Z in the garage.

Since I had torn the engine down to its bare components I took the opportunity to make some changes: increased the size of the turbocharger, increased bore and stroke of the cylinder/piston, improved the fuel distribution, and improved the flow of air with things like porting the heads and an inter-cooler.

Continue reading “Megasquirting My 1983 Datsun Z” →

The Quantum Eraser

September 7, 2016 by Will Sweatman 64 Comments

Richard Feynmann noted more than once that complementarity is the central mystery that lies at the heart of quantum theory. Complementarity rules the world of the very small… the quantum world, and surmises that particles and waves are indistinguishable from one other. That they are one and the same. That it is nonsensical to think of something, or even try to visualize that something as an individual “particle” or a “wave.” That the particle/wave/whatever-you-want-to-call-it is in this sort of superposition, where it is neither particle nor wave. It is only the act of trying to measure what it is that disengages the cloaking device and the particle or wave nature is revealed. Look for a particle, and you’ll find a particle. Look for a wave instead, and instead you’ll find a wave.

Complementarity arises from the limits placed on measuring things in the quantum world with classical measuring devices. It turns out that when you try to measure things that are really really really small, some issues come up… some fundamental issues. For instance, you can’t really know exactly where a sub-atomic particle is located in space. You can only know where it is within a certain probability, and this probability is distributed through space in the form of a wave. Understanding uncertainty in measurement is key to avoiding the disbelief that hits you when thinking about complementarity.

This article is a continuation of the one linked above. I shall pick up where I left off, in that everyone agrees that measurement on the quantum scale presents some big problems. However, not everyone agrees what these problems mean. Some, such as Albert Einstein, say that just because something cannot be measured doesn’t mean it’s not there. Others, including most mainstream physicists, say the opposite — that if something cannot be measured, it for all practical purposes is not there. We shall continue on our journey by using modern technology to peer into the murky world of complementarity. But first, a quick review.

Continue reading “The Quantum Eraser” →