Fail Of The Week: Good Prosthetic Hand Design Goes Bad

July 28, 2017 by Dan Maloney 31 Comments

Is this a case of a good design gone wrong in the build phase? Or is this DIY prosthetic arm a poor design from the get-go? Either way, [Will Donaldson] needs some feedback, and Hackaday is just the right place for that.

Up front, we’ll say kudos to [Will] for having the guts to post a build that’s less than successful. And we’ll stipulate that when it comes to fully articulated prosthetic hands, it’s easy to fail. His design is ambitious, with an opposable thumb, fingers with three phalanges each, a ball and socket wrist, and internal servos driving everything. It’s also aesthetically pleasing, with a little bit of an I, Robot meets Stormtrooper look.

But [Will]’s build was plagued with print problems from the start, possibly due to the complex nature of the bosses and guides within the palm for all the finger servos. Bad prints led to creaky joints and broken servos. The servos themselves were a source of consternation, modified as they were for continuous rotation and broken apart for remotely mounting their pots in the hand’s knuckles. The video below relates the tale of woe.

There’s a lot to admire with [Will]’s build, but it certainly still has its issues. He’s almost to the point of other more successful DIY hand builds but just needs a little help. What say you in the comments line? Continue reading “Fail Of The Week: Good Prosthetic Hand Design Goes Bad” →

Where A Wood Shop Goes, A Hackerspace Follows

July 28, 2017 by John Baichtal 18 Comments

The 2×4 Contest at my local hackerspace captured my interest. The challenge was to build something cool out of a single eight-foot 2×4 with the winner getting free wood storage in the space. I had half an idea for a project, but I ran out of time and never even started it. My idea was to cut the board into half-thickness strips and glue them edge-to-edge with some biscuits holding them together — to basically make wider, thinner boards to do… something cool with it.

One of the entries is pictured above. [Jon Alt] designed this clock and phone charger that includes a capacitive charger for his smart watch. He makes use of the 2×4’s grain to make a gorgeous enclosure, carving away the rear of the front panel so only a credit-card’s thickness of wood remained, allowing the 7-segments to shine through. The other entries were great as well and I especially liked the 2×4 guitar.

Mostly what interested me about the contest was what it showed about the wood shop: thanks to the volunteers and board, that is a wood shop doing well. Stuff is going on! A sad wood shop doesn’t hold contests. By extension, when the shop is doing well, that means the hackerspace is also doing well.

A wood shop is one of those areas of a hackerspace that is tool-driven. It’s not just a gathering place for like-minded folks; people go to use a specific tool or tools they can’t afford, and let’s face it, there’s always tools to buy that costs a bunch of money.

I’ve seen this particular shop begin as an empty concrete room with a cheap drill press and someone’s old bandsaw. Pretty soon worktables, shelving, and storage were built. More tools arrived, some donated, some loaned, some purchased with dues. So how can other spaces replicate this wood shop success story?

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Rotary Phones And The Birth Of A Network

July 26, 2017 by Al Williams 85 Comments

I can’t help but wonder how long it will be before the movie title “Dial M for Murder” becomes mysterious to most of the population. After all, who has seen a dial phone lately? Sure, there are a few retro phones, but they aren’t in widespread use. It may not be murder, but it turns out that the dial telephone has its roots in death — or at least the business of death. But to understand why that’s true, you need to go back to the early days of the telephone.

Did you ever make a tin can phone with a string when you were a kid? That dates back to at least 1667. Prior to the invention of what we think of as the telephone, these acoustic phones were actually used for specialized purposes.

We all know that [Alexander Graham Bell] made a working telephone over a wire, drawing inspiration from the telegraph system. However, there’s a lot of dispute and many others about the same time were working on similar devices. It is probably more accurate to say that [Bell] was the first to successfully patent the telephone (in 1876, to be exact).

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Friday Hack Chat: Crowd Supply

July 26, 2017 by Brian Benchoff 8 Comments

Crowdfunding is a mixed bag, at best. On one hand, you have fantastically successful products like Pebble, Oculus, and the Kano personal computer that managed to take in money, turn out a product, and become a successful company. (If even just for a while, the Pebble was great.) On the other hand, you have obvious scams like a color-picking pen that are run by a literal Nigerian scammer.

Crowd Supply is different. Unlike other crowdfunding platforms, to get on Crowd Supply you’ll need a working prototype. Where other platforms can measure their success by how many campaigns were successfully funded, and how many of those campaigns successfully delivered rewards to backers, I’m not aware of any Crowd Supply campaigns that have ever failed completely.

For this week’s Hack Chat, we’ll be talking with [Josh Lifton], CEO of Crowd Supply. Topics will include determining if there’s a market for your product, the ins and outs of fulfillment, to shipping your product. We’re taking questions from the community, and there’s a question sheet we’ll be reading from.

Josh has a PhD from the MIT Media Lab and holds a BA in physics and mathematics from Swarthmore College. Prior to Crowd Supply, Josh worked in a variety of technology settings, from instrumenting thousands of audience members with custom wearable computers for a Cirque du Soleil performance to, most recently, serving as head of engineering at Puppet Labs.

Here’s How To Take Part:

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This Hack Chat will take place at noon Pacific time on Friday, July 28th. Confused about where and when ‘noon’ is? Here’s a time and date converter!

Log into Hackaday.io, visit that page, and look for the ‘Join this Project’ Button. Once you’re part of the project, the button will change to ‘Team Messaging’, which takes you directly to the Hack Chat.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Fail Of The Week: How Not To Use Pushbuttons

July 25, 2017 by Jenny List 48 Comments

If you are a regular at creating printed circuit boards, it is likely that somewhere in your shop there will be a discard pile of boards on which you placed a component in the wrong orientation such that it would not work. It’s easily done, and don’t be shy to admit it if it’s happened to you.

[Bill] was making his own ARM developer board, taking inspiration from the ARM Pro Mini. He produced his PCB design and sent it off to the board house, and in due course received and reflow soldered a batch of beautiful dev boards. On power-up though, something was wrong! No USB device detected on his computer, a disaster. A lot of studying board and schematic led to the discovery that his push-button switches had been placed at 90 degrees to the orientation it should have had, leaving them in a permanently “on” position.

The PCB bug makes this is a Fail Of The Week post, but he transformed into a win with some experimentation with the switch outline in KiCAD before finding a way to mount the switches on the pads at 45 degrees, covering three of the pads. Well done, and well done for admitting the error.

[Editor’s note: been there, done that. One way to prevent the error is to only connect to diagonally opposite pins of the tact switch, so the rotation doesn’t matter.]

Having earlier asked others to come clean with their PCB mistakes, it’s probably appropriate to admit that Hackaday scribes are just as fallible as [Bill] when it comes to PCB layouts. Somewhere there may still be a board on this bench with a QFN microcontroller bodged on at 90 degrees to its original orientation, with cut tracks and tiny wire runs.

Whether you are a seasoned PCB pro or a wet-behind-the-ears rookie, our Creating a PCB In Everything series should be of interest.

KIM-1 To COSMAC Elf Conversion — Sort Of

July 25, 2017 by Al Williams 11 Comments

In the mid-1970s, if you had your own computer, you probably built it. If you had a lot of money and considerable building skill, you could make an Altair 8800 for about $395 — better than the $650 to have it built. However, cheaper alternatives were not far behind.

In 1976, Popular Electronics published plans for a computer called the COSMAC Elf which you could build for under $100, and much less if you had a good junk box. The design was simple enough that you could build it on a piece of perf board or using wire wrap. We featured the online archive of the entire Popular Electronics collection, but hit up page 33 of this PDF if you want to jump right to the article that started it all. The COSMAC Elf is a great little machine built around a 40-pin RCA 1802 processor, and for many was the first computer they owned. I lost my original 1802 computer in a storm and my recent rebuild in another completely different kind of storm. But there is a way to reclaim those glory days without starting from scratch. I’m going to repurpose another retro-computing recreation; the KIM-1.

I’ll admit it, Rewiring a real KIM-1 to take an 1802 CPU would be difficult and unnecessary and that’s not what this article is about. However, I did have a KIM UNO — [Oscar’s] respin of the classic computer using an Arduino mini pro. Looking at the keyboard, it occurred to me that the Arduino could just as easily simulate an 1802 as it could a 6502. Heck, that’s only two digits different, right?

The result is pretty pleasing. A “real” Elf had 8 toggle switches, but there were several variations that did have keypads, so it isn’t that far off. Most Elf computers had 256 bytes of memory (without an upgrade) but the 1802 UNO (as I’m calling it) has 1K. There’s also a host of other features, including a ROM and a monitor for loading and debugging programs that doesn’t require any space in the emulated 1802.

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Monster Mindstorms Delta Bot Delicately Picks Candy

July 24, 2017 by John Baichtal 6 Comments

A group of embedded developers from Sioux Embedded Systems in Eindhoven, the Netherlands, wanted to get experience working on Microsoft .Net. To make it fun they made it their project to produce a LEGO train with visitors at LEGO World, the official LEGO convention in the Netherlands. The team developed an application in C# to fully automate the train, with Mindstorms NXT and EV3 bricks as well as LEGO Power Functions motors controlling everything.

The train project carries a simple premise: the visitor chooses one of four colors, and the train goes and picks up a piece of simulated candy with the matching color. Called Sioux.net on Track, the project has produced a new train every year since 2012 with improvement goals in place to add features with every version. Ironically, the least interesting part of the setup is the actual train and track. The team’s creativity comes to the fore in two areas of the project: the method by which the candy color is selected, and the assembly that dispenses the correct color into the train car.

Team member [Hans Odenthal] has built candy-grabbers for various years’ trains. He learned about the ABB FlexPicker and this year decided to build a delta robot for the layout. It consists of huge girders constructed from 5×9 and 5×11 Technic beam frames held together with more Technic beams and hundreds of connector pegs. The three arms each move on a pair of turntables which are geared down to provide as much torque as possible — the fake candy pieces are light, but the arms themselves weigh a lot. [Hans] ended up revamping the gearboxes to up the ratio from 1:5 to 1:25.

Continue reading “Monster Mindstorms Delta Bot Delicately Picks Candy” →