Truly Terrible Dimensioned Drawings

December 14, 2017 by Brian Benchoff 147 Comments

I’m in the planning stages of a side project for Hackaday right now. It’s nothing too impressive, but this is a project that will involve a lot of electromechanical parts. This project is going to need a lot of panel mount 1/8″ jacks and sockets, vertical mount DIN 5 connectors, pots, switches, and other carefully crafted bits of metal. Mouser and Digikey are great for nearly every other type of electrical component, but when it comes to these sorts of electromechanical components, your best move is usually to look at AliExpress or DealExtreme, finding something close to what you need, and buying a few hundred. Is this the best move for a manufacturable product? No, but we’re only building a few hundred of these things.

I have been browsing my usual Internet haunts in the search for the right bits of stamped brass and injection molded plastic for this project, and have come to a remarkable conclusion. Engineers, apparently, have no idea how to dimension drawings. Drafting has been a core competency for engineers from the dawn of time until AutoCAD was invented, and now we’re finally reaping the reward: It’s now rare to find a usable dimensioned drawing on the Internet.

This post is going to be half rant, half explanation of what is wrong with a few of the dimensioned drawings I’ve found recently. Consider this an example of what not to do. There is no reason for the state of engineering drawing to be this bad.

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Britain Invented Rock-N-Roll, And Other Stories

August 28, 2017 by Jenny List 58 Comments

An elderly relative of mine used to get irate at the BBC news. When our Prime Minister [Edward Heath] or another of her bêtes noirs of the day came on, she’d rail at the radio or the TV, expressing her views to them in no uncertain terms. It taught a young me a lot about the futility of shouting at the telly, as well as about making a spectacle of oneself.

The ISS in flight. NASA(Public Domain) — The ISS in flight. NASA [Public domain].

The other evening though I found myself almost at the point of shouting at a TV programme, and since it’s one with a clear message about technology I feel it’s worth sharing here. The programme in question was one of the Impossible Engineering series, and it was talking about the technology behind the International Space Station. It was recent enough to include last year’s mission involving [Tim Peake], so it was by no means a show dredged from the archives.

All very well, you say. Impossible Engineering‘s format of looking at a modern engineering marvel and tracing the historical roots of some of its innovations would find fertile ground in the ISS, after all it’s one of our most impressive achievements and could easily provide content for several seasons of the show. And I’ll give them this, they did provide an interesting episode.

The trouble was, they made an omission. And it wasn’t just a slight omission, one of those minor cock-ups that when we Hackaday scribes make them the commenters pounce upon with glee, this one was a doozy. They managed to fill an hour of television talking about space stations and in particular a space station that was assembled by multiple countries under an international co-operation, without mention of any of the Russian technology that underpins much of its design. An egregious example among many was their featuring a new Boeing capsule designed to touchdown on land rather than on water as a novel invention, when as far as I am aware every Russian capsule ever made has performed a land-based touchdown.

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MEMS: The Biggest Word In Small

June 26, 2017 by Al Williams 20 Comments

What’s tiny and on track to be worth $22 billion dollars by 2018? MEMS (Micro Electrical Mechanical Systems). That’s a catch-all phrase for microscopic devices that have moving parts. Usually, the component sizes range from 0.1 mm to 0.001 mm, which is tiny, indeed. There are some researchers working with even smaller components, sometimes referenced as NEMS (Nano Electrical Mechanical Systems).

Resonant Cantilever by [Pcflet01], CC BY-SA 3.0

MEMS have a wide range of applications including ink jet printers, accelerometers, gyroscopes, microphones, pressure sensors, displays, and more. Many of the sensors in a typical cell phone would not be possible without MEMS. There are many ways that MEMS devices are built, but just to get a flavor, consider the cantilever (see right), one of the most common MEMS constructions.

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Unlikely Cascade Of Failures Leads To Microwave’s Demise

June 16, 2017 by Dan Maloney 30 Comments

Surely a blown light bulb can’t kill a microwave oven, right? You might not expect it to, but that was indeed the root cause of a problem that [mikeselecticstuff] recently investigated; the cascade of failures is instructive to say the least.

While the microwave that made its way to [mike]’s bench wasn’t exactly engineered to fail, it surely was not designed to succeed. We won’t spoil the surprise, but suffice it to say that his hopes for a quick repair after the owner reported a bang before it died were dashed by an arc across the interior light bulb that put a pulse of mains voltage in places it didn’t belong. That the cascade of failures killed the appliance is a testament to how designing to a price point limits how thoroughly devices can be tested before production runs in the millions are stuffed into containers for trips to overseas markets.

Even though [mike] made his best effort to adhere to the Repair Manifesto, the end result was a scrapped microwave. It wasn’t a total loss given the interesting parts inside, but a disappointment nonetheless unless it forces us to keep in mind edge-case failure modes in our designs.

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These Engineering Ed Projects Are Our Kind Of Hacks

May 25, 2017 by Mike Szczys 23 Comments

Highly polished all-in-one gear for teaching STEM is one way to approach the problem. But for some, they can be intimidating and the up-front expenditure can be a barrier to just trying something before you’re certain you want to commit. [Miranda] is taking a different approach with the aim of making engineering education possible with junk you have around the house. The point is to play around with engineering concepts with having to worry about doing it exactly right, or with exactly the right materials. You know… hacking!

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Juicero: A Lesson On When To Engineer Less

April 26, 2017 by Brian Benchoff 174 Comments

Ben Einstein, a product designer and founder at Bolt, a hardware-based VC, recently got his hands on a Juicero press. This desktop juice press that only works with proprietary pouches filled with chopped fruits and vegetables is currently bandied in the tech press as evidence Silicon Valley has gone mad, there is no future in building hardware, and the Internet of Things is a pox on civilization. Hey, at least they got the last one right.

This iFixit-style tear down digs into the Juicero mixer in all its gory details. It’s beautiful, it’s a marvel of technology, and given the engineering that went into this machine, it was doomed to fail. Not because it didn’t accomplish the task at hand, but because it does so with a level of engineering overkill that’s delightful to look at but devastating to the production cost.

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Alan Yates: Why Valve’s Lighthouse Can’t Work

December 21, 2016 by Elliot Williams 51 Comments

[Alan Yates] is a hacker’s engineer. His job at Valve has been to help them figure out the hardware that makes virtual reality (VR) a real reality. And he invented a device that’s clever enough that it really should work, but difficult enough that it wasn’t straightforward how to make it work.

In his presentation at the Hackaday Supercon 2016, he walked us through all of the design and engineering challenges that were eventually conquered in getting the Lighthouse to market. We’re still a bit overwhelmed by the conceptual elegance of the device, so it’s nice to have the behind-the-scenes details as well.