The Practical Potato Cell

October 18, 2015 by James Hobson 32 Comments

Potato batteries, lemon batteries, they’re all good fun for the classroom — but is there a way of making them better? [Marcel Varallo] decided to give it a shot — and we gotta admit, it’s a pretty cool idea!

Normally for these fruit and vegetable batteries you poke some leads into the battery, connect it to a clock, and bob’s your uncle. But what if we made them resemble batteries? [Marcel] took some copper pipe, cut it down to size, and poked it through a potato. Now he had a potato-cored, copper tube. Stick a zinc nail in the middle, and you’ve got yourself a battery cell! Or as [Marcel] likes to put it.. a Mar-Cell. Or the more scientific term.. the Solanum tuberosum based electron differencer V1.0.

Each potato cell produces approximately 0.8V, so if you throw eight in series, you’ll have the equivalent of a 6V battery, just maybe not the same mAh rating.

For another cool way to demonstrate electricity to youngsters, we love this lemon battery hack — it’s actually quite elegant.

Electronic Ruler Works Out Logic Truth Tables

October 13, 2015 by Mike Szczys 23 Comments

Like [Brad], we’ve seen a number of PCB rulers out there. [Brad] was looking to take the idea and run with it. His DigiRule is a ruler with a logic gate simulator. What he built is a mash-up between PCB rulers, and the concept of electronic business cards.

All told it simulates seven logic gates, four flip-flops, and includes a four-bit counter. On one end of the ruler a CR1220 battery feeds the 18F43K20 which is performing the logic operations using buttons and LEDs. Of course the truth tables are printed on the back silk-screen, but playing with the lights is a lot more fun. We do find it fairly amusing that the centimeters on the bottom of the ruler are notated in binary.

It makes a lot more sense to hand out rulers than business cards; people might actually use them after you leave and you can still include contact info. This form-factor also breaks the mold. You can have a lot more space on a ruler and you’re not constrained by thickness (although [Limpkin] solved that problem). While we’re on the topic of business cards [ch00f’s] USB etch-a-sketch style card and this logic-based information delivery device top our favorites list.

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Citizen Scientist: Forrest Mims

October 13, 2015 by Nava Whiteford 140 Comments

Before the modern notion of the citizen scientist lies the earlier ideal of the independent scientist. Scientists outside of the academic community but engaging with it. These days citizen scientists are often seen as valuable assistants in the scientific process, helping collect and process data in a quantity which would be otherwise intractable.

In the past however, independent scientists had a far more central role. Galileo, Kepler, Darwin and Hooke were all self funded at various points in their careers. More recently independent scientist Peter Mitchell won the Nobel prize for Chemistry in 1978 for his foundational research into cell biochemistry and the development of the chemiosmotic hypothesis.

Sadly, peer-reviewed scientific contributions by scientists un-sponsored by a research organization are now few and far between. In this short series we hope to highlight the efforts of these lone researchers with particular reference to the tools they’ve had to hack together on a budget in their scientific quests (if you know an independent researcher you think we should feature, please comment below!).

In Hacker circles Forrest Mims is perhaps best known for his series of electronics books and the unforgeable Atari Punk Console. But it’s his ability to engage with the scientific community as an independent researcher through a series of well thought out scientific articles that interests us here. Contributions made all the more significant by his lack of formal scientific training.

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Jewelry Meets Carpentry With Bentwood Rings

October 12, 2015 by Adam Fabio 22 Comments

[Dorkyducks] is a bit of a jeweler, a bit of a carpenter, and a bit of a hacker. They’ve taken some time to document their technique for making bentwood rings. Bentwood is technique of wetting or steaming wood, then bending or forming it into new shapes. While the technique is centuries old, this version gets a bit of help from a modern heat source: The microwave oven. [Dorkyducks] starts with strips of veneer, either 1/36″ or 1/42″ thick. The veneer is cut into strips 1/2″ wide by about 12″ long, wrapped in a wet paper towel, and microwaved. The microwave heats the water in the towel, steaming it into the wood. This softens the wood fibers, making the entire strip flexible. The softened wood is then wrapped around a wooden preform dowel and allowed to dry for a day or two.

Once dry, the wood will hold the circular shape of the dowel. [Dorkyducks] then uses masking tape to tack the wood down to a new dowel which is the proper ring size for the wearer. Then it’s a superglue and wrapping game. The glue holds the laminated veneer together, and gives the ring it’s strength. From there it’s sanding, sanding, sanding. At this point, the ring can be shaped, and inlays added. [Dorkyducks] shows how to carve a ring and insert a gemstone in this gallery. The final finish is beeswax and walnut oil, though we’d probably go for something a bit longer lasting – like polyurethane.

Heathkit: Live, Die, Repeat

October 8, 2015 by Brian Benchoff 91 Comments

There is no company that has earned more goodwill from electronic tinkering hobbyists than Heathkit. For more than fifty years, Heathkit has been the measure all other electronic kit manufacturers have been compared to. Kits for everything – from televisions to radios to computer terminals – were all sold by Heathkit, and even now, nearly a quarter century since the last kit left the warehouse, there is still a desire for this manufacturer to rise like a phoenix from the ashes. Heathkit lives once more, and this time it might be for real.

In recent years, Heathkit has had a confusing, if not troubled business plan. The company started manufacturing its signature products – electronic kits of every kind – in 1947. Production of these kits ended in 1992, and the company went on for another few years manufacturing educational materials and lighting controls. In 2011, Heathkit said they were back in the kit business, before shutting down a year later.

In 2013, an official Heathkit Facebook page was launched, a reddit AMA was held, and a mysterious stranger in the Hackaday comments section found a geocache placed by someone at Heathkit in a Brooklyn park. Absolutely nothing happened in 2014, or at least no one cared enough to hire a PI, which brings us to today’s announcement: Heathkit lives yet again.

This morning, the president of Heathkit sent a message to the ‘Heathkit Insiders’ email group explaining the goings on and new happenings:

We’ve designed and developed a wide range of entirely new kit products. We authored the manuals for these kits, complete with the beautiful line art you rely on, preserving and respecting our iconic historic Heathkit style. We developed many new inventions and filed patents on them. We relocated Heathkit, and set up a factory, and a warehouse, and offices, in Santa Cruz, California, near Silicon Valley. We built the back office infrastructure, vendor and supply chain relationships, systems, procedures, operations methods, and well-thought-out corporate structure that a manufacturing company needs to support its customers, to allow us to scale instantly the day we resume major kit sales. All this effort enables us to introduce a fleet of new kits and helps ensure Heathkit can grow, prosper, and continue to bring you great new products for a very long time.

The new Heathkit shop features their newest product, the Explorer Jr. AM Radio Receiver kit, a small kit radio available for $150. It’s actually a rather interesting kit with a nice design and an air variable cap for tuning, just like radios from a century ago. Whether anyone will pay $150 for an AM receiver in this century is another question entirely. The 21st century rebirth of Heathkit doesn’t just mean kits; they’re making apps now, with the first release being a crystal design tool for Android.

Virtually everyone in this little corner of the Internet, from Adafruit to Sparkfun, to Make magazine to everyone with a 3D printer owes a debt to Heathkit. This is the company that first turned DIY electronics into a successful business. Heathkit was the first, and they deserve to be recognized as the pioneers of the field.

The Donner Party were pioneers, too; just because you’re breaking new ground doesn’t mean you’re successful. The Heathkit of the 90s shuttered its doors for a reason. The factors behind the 1992 closing – cheap stuff from China, and the fact that not many people want to build their own electronics – are still with us. Still, the market for DIY electronics may be big enough, and Heathkit’s back catalog may be diverse enough that I won’t have to write another ‘Heathkit dies yet again’ post in a year or so. We can only hope.

How Analog Tide Predictors Changed Human History

October 8, 2015 by Kristina Panos 17 Comments

If you’re completely landlocked like I am, you may dream of ocean waves lapping at the shore, but you probably don’t think much about the tides. The movement of the ocean tides is actually quite important to many groups of people, from fishermen to surfers to coastal zone engineers. The behavior of the tides over time is helpful data for those who study world climate change.

Early tide prediction was based on observed changes in relation to the phases of the Moon. These days, tide-predicting is done quickly and with digital computers. But the first purpose-built machines were slow yet accurate analog computation devices that, as they were developed, could account for increasing numbers of tidal constituents, which represent the changes in the positions of tide-generating astronomical bodies. One of these calculating marvels even saved the Allies’ invasion of Normandy—or D-Day— in World War II.

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[Bunnie Huang’s] Hardware Talks Top Your Watch List

October 7, 2015 by Mike Szczys 14 Comments

When [Bunnie] talks, we listen. He is a fount of product engineering knowledge, having seen many of his own products through from concept to market, and frequently helping others do the same. Of course having the knowledge is one thing, but he is also an accomplished speaker who knows what is important and how to share it in a way which is meaningful to others. The latest example of this is a pair of Engineering Talks he gave at Highway 1.

It’ll take you less than twenty minutes to get through the two videos. The first focuses on documentation for manufacturing. What do you need to include on a bill of materials sent to the factory? [Bunnie] has a set of gotchas which illustrate how vital this is. He also discusses how to handle design changes once the manufacturing wheels are already in motion. The second clip covers how Design for Manufacture relates to the actual cost of a production run. We hope there are more of these clips in the publishing pipeline so we’re keeping our eye on this channel.

The two videos are embedded below and at the time of writing had just a couple dozen views each and only one comment between the two of them. It seems sacrilege to say this, but we agree with that YouTube comment; these videos are gold.

Want to check out one of [Bunnie’s] latest projects? It’s a radio-based interactive badge.

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