Fail Of The Week: The Spot Welder Upgrade That Wasn’t

April 22, 2018 by Dan Maloney 28 Comments

Even when you build something really, really nice, there’s always room for improvement, right? As it turns out for this attempted upgrade to a DIY spot welder, not so much.

You’ll no doubt recall [Mark Presling]’s remarkably polished and professional spot welder build that we featured some time ago. It’s a beauty, with a lot of thought and effort put into not only the fit and finish but the function as well. Still, [Mark] was not satisfied; he felt that the welder was a little underpowered, and the rewound microwave oven transformer was too noisy. Taking inspiration from an old industrial spot welder, he decided to rebuild the transformer by swapping the double loop of battery cable typically used as a secondary with a single loop of thick copper stock. Lacking the proper sized bar, though, he laminated multiple thin copper sheets together before forming the loop. On paper, the new secondary’s higher cross-sectional area should carry more current, but in practice, he saw no difference in the weld current or his results. It wasn’t all bad news, though — the welder is nearly silent now, and the replaced secondary windings were probably a safety issue anyway, since the cable insulation had started to melt.

Given [Mark]’s obvious attention to detail, we have no doubt he’ll be tackling this again, and that he’ll eventually solve the problem. What suggestions would you make? Where did the upgrade go wrong? Was it the use of a laminated secondary rather than solid bar stock? Or perhaps this is the best this MOT can do? Sound off in the comments section.

Continue reading “Fail Of The Week: The Spot Welder Upgrade That Wasn’t” →

Life On Contract: Lowering Your Cost Without Dropping Your Price

April 20, 2018 by Donald Papp 17 Comments

Last time in Life on Contract, I discussed ways to figure out a starting point on how much to charge for your services. However, sometimes you and a client may wish to work together but for some reason they cannot (or do not wish to) pay what you have decided to charge. If you are inexperienced, it can be tempting to assume you have overpriced yourself and discount down to what they are willing to pay. But if your price is a number you have chosen for reasons you can explain, dropping it is not something you should do unless you have thought about it carefully.

Instead of just agreeing to do the same work but for less money, it is often possible to offer a lower overall cost without cheapening the value of your work. I’ll share a process I use to find opportunities to make this happen.

It Should be Win-Win, Not Hard Sell

The best case scenario is a client wants your service, your cost is within their budget, and everyone agrees to work together. Tragically, the process isn’t always that smooth. If cost is an issue, the alternative to lowering your price is to fine-tune what you provide to better fit the actual needs. To do that, you will need two things:

A detailed understanding of your own time and costs for the work.
Knowledge of what things your client considers most important.

By intimately knowing your own costs, you can figure out where to make savings without scrimping on the things your client considers important.
Continue reading “Life On Contract: Lowering Your Cost Without Dropping Your Price” →

Mechanisms: Hook And Loop Fasteners

April 19, 2018 by Dan Maloney 35 Comments

As a species, we’ve done a pretty good job at inventing some useful devices. But as clever as we think we are, given sufficient time, natural selection will beat us at our game at almost every turn. So it makes sense that many of our best inventions are inspired by nature and the myriad ways life finds to get DNA from one generation to the next.

Hook and loop fasteners are one such design cribbed from nature, and the story behind this useful mechanism is a perfect example that a prepared mind, good observation skills, and a heck of a lot of perseverance are what it takes to bring one of Mother Nature’s designs to market.

Editor’s Note: As some predicted in the comments section, we were contacted by representatives of Velcro Companies and asked to change all mentions in this article to either VELCRO® Brand Fastener or to use the generic “Hook and Loop” term. If it seems weird that we’re calling this hook and loop, now you know why.

Continue reading “Mechanisms: Hook And Loop Fasteners” →

When Hackerspace Directors Burn Out

April 18, 2018 by Jenny List 78 Comments

A friend of mine once suggested that there should be a support group for burned-out former hackerspace directors. We could have our own Village of the Damned at summer camps, where we’d sit moodily in the gathering twilight sipping our bourbon and Club Mate and decrying whatever misfortunes came to our space to leave such visible mental scars, or gazing hollow-eyed into the laser-tinged haze and moving gently to the pulse of the chiptune music. “See that’s Jenny over there, she don’t say much“. Hackerspace noir, where the only entry criterion is being crazy enough to stand for election to your space’s board.

You can tell [Dr. Seuss] is thinking about his next volume: <em>How The Grinch Stole Whoville Hackspace</em>. Al Ravenna, World Telegram [Public domain]. — You can tell [Dr. Seuss] is thinking about his next volume: *How The Grinch Stole Whoville Hackspace*. Al Ravenna, World Telegram [Public domain].

There must be spaces somewhere that live in such perfect harmony, in which a happy membership support a board for whom everything falls into place. Maybe the makerspace in [Dr. Seuss]’s Whoville would have that kind of atmosphere, but the reality of life is that every group is made up of both Grinch and Who. Keeping a diverse group of people harmonious is a huge challenge, but that’s what hackerspaces are really about — the people make the space.

There are several defined periods in the gestation of a hackerspace, and at least from where I’m sitting they relate to its member count. Some spaces pass through them all as they grow, while others are lucky enough to reach an equilibrium and spare themselves some of the drama.

If you recognise yourselves in some of the following then you have my commiserations, while if your space hasn’t got there yet or has managed to dodge some of the bullets then consider yourselves lucky.

Continue reading “When Hackerspace Directors Burn Out” →

Friday Hack Chat: Circuit Board Art

April 18, 2018 by Brian Benchoff 14 Comments

We are now in a golden age of printed circuit boards. It wasn’t too long ago that making your own circuit boards either involved a lot of money, or slightly less money and using some proprietary garbage PCB layout tool. Now, every board house speaks Gerber, and you can get a ten-pack of PCBs from China for five bucks. This incredible cost reduction means people are making art with printed circuit boards. We’ve seen portraits, landscapes, and memes. This is truly the beginning of a new artistic medium rendered in fiberglass and soldermask.

Check out this blinky bit of art nouveau. There is a facebook group for PCB paintings, and some of the Badgelife crew are relying on woodcut and linoleum engraving techniques to create works of art in copper and fiberglass.

For this week’s Hack Chat, we’re going to be talking all about PCB artwork. Our guest for this week’s Hack Chat will be [Andrew Sowa], an electrical engineer, a vocal advocate of KiCad, and the guy who made more of me money. The Benchoff Nickel was created by simply taking some of the fantastic illustrations from Hackaday’s own [Joe Kim] and applying KiCad’s Bitmap2Component tool. Since the creation of the nickel, [Andrew] has been working on extending his technique to cross-hatching, backlighting, and halftones.

In this Hack Chat, we’re going to be talking all about PCB artwork, including the very beginnings of PCB art where engineers hid a few easter eggs in the PCBs of Xboxen and other consumer electronics. Topics covered will be bitmap to SVG conversion (in Inkscape and Illustrator), KiCad footprint creation, and the more technical side of things with the limitations of PCB fabrication and the slightly different shades of beige FR4 comes in.

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week is just like any other, and we’ll be gathering ’round our video terminals at noon, Pacific, on Friday, April 20th. How can there be time zones when the Earth has four days simultaneously for each rotation? You erroneously measure time from one corner. Here’s a clock counting down the time until the Hack Chat starts.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

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: An Electric Bicycle, Powered By AA Batteries

April 17, 2018 by Brian Benchoff 47 Comments

Very slowly, some very cool parts are coming out on the market that will make for some awesome builds. Supercapacitors are becoming a thing, and every year, the price of these high power supercaps go a little lower, and the capacity gets a little higher. It’s really only a matter of time before someone hacks some supercaps into an application that’s never been seen before. The Navy is doing it with railguns, and [David] is building an electric bike, powered by AA batteries. While [David]’s bike technically works with the most liberal interpretation of ‘technically’, it’s the journey that counts here.

This project began as an investigation into using supercapacitors in an electric bicycle. Supercaps have an energy density very much above regular capacitors, but far behind lithium cells. Like lithium cells, they need a charge balancer, but if you manage to get everything right you can trickle charge them while still being able to dump all that power in seconds. It’s the perfect application for a rail gun, or for slightly more pedestrian applications, an electric bike with a hill assist button. The idea for this build would be to charge supercaps from a bank of regular ‘ol batteries, and zoom up a hill with about fifteen seconds of assistance.

The design of the pulsed power DC supply is fairly straightforward, with a mouthful of batteries feeding the supercap array through boost regulators, and finally going out to the motor through another set of regulators. Unfortunately, this project never quite worked out. Everything worked; it’s just this isn’t the application for the current generation of supercapacitors. There’s not enough energy density in [David]’s 100F supercaps, and the charging speed from a bunch of AA batteries is slow. For fifteen minutes of charging, [David] gets about fifteen seconds of boost on his bike. That’s great if you only ever have one hill to climb, but really useless in the real world.

That doesn’t mean this project was a complete failure. [David] now has a handy, extremely resilient array of supercaps that will charge off of anything and provide a steady 24V for a surprising amount of time. Right now, he’s using this scrapped project as a backup power supply for his 3D printer. That 100 Watt heated bed slurps down the electrons, but with this repurposed supercap bank, it can survive a 20 second power outage.

It’s a great project, and even if the technology behind supercaps isn’t quite ready to be used as a boost button on an electric bike, it’s still a great example of DIY ingenuity. You can check out [David]’s demo of the supercap bank in action below.

Continue reading “Fail Of The Week: An Electric Bicycle, Powered By AA Batteries” →

TensorFlow In Your Browser

April 16, 2018 by Al Williams 24 Comments

If you want to explore machine learning, you can now write applications that train and deploy TensorFlow in your browser using JavaScript. We know what you are thinking. That has to be slow. Surprisingly, it isn’t, since the libraries use Graphics Processing Unit (GPU) acceleration. Of course, that assumes your browser can use your GPU. There are several demos available, include one where you train a Pac Man game to respond to gestures in your webcam to control the game. If you try it and then disable accelerated graphics in your browser options, you’ll see just what a speed up you can gain from the GPU.