DIY 9V Battery

Volta’s pile — the first battery — was little more than silver and zinc discs separated by paper soaked in salt water. A classic classroom experiment is to build a pile from copper pennies, tin foil, and vinegar or lemon juice. [Omars2] has a different take on this old experiment. He creates a 9V battery using some zinc screws, copper wire, and salt water. There’s a video of the battery, below.

A syringe piston serves as a substrate for the cells, and each cell is just a screw with paper wrapped around it and then 35 turns of copper wire on top of that. The battery is soaked in salt water, although we suspect vinegar or lemon juice would work even better. Heating the electrolyte is also a good idea.

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Hackaday Prize Entry: Modular, Rapid Deployment Power Station

After a disaster hits, one obvious concern is getting everyone’s power restored. Even if the power plants are operational after something like a hurricane or earthquake, often the power lines that deliver that energy are destroyed. While the power company works to rebuild their infrastructure, [David Ngheim]’s mobile, rapid deployment power station can help get people back on their feet quickly. As a bonus, it uses renewable energy sources for power generation.

The modular power station was already tested at Burning Man, providing power to around 100 people. Using sets of 250 Watt panels, wind turbines, and scalable battery banks, the units all snap together like Lego and can fit inside a standard container truck or even the back of a pickup for smaller sizes. The whole thing is plug-and-play and outputs AC thanks to inverters that also ship with the units.

With all of the natural disasters we’ve seen lately, from Texas to Puerto Rico to California, this entry into the Hackaday Prize will surely gain some traction as many areas struggle to rebuild their homes and communities. With this tool under a government’s belt, restoration of power at least can be greatly simplified and hastened.

Power Through a Hurricane

When living in an area that is prone to natural disasters, it’s helpful to keep something on hand for backup power. While a large number of people chose to use generators, they are often unreliable (or poorly maintained), noisy, produce dangerous carbon monoxide, or run on a fuel supply that might not be available indefinitely. For truly reliable backup power, [Jay] has turned to a battery bank to ride through multi-day power outages.

While the setup doesn’t run his whole house, it isn’t intended to. One of the most critical things to power is the refrigerator, so this build focuses on keeping all of his food properly stored through the power outage. During the days following Hurricane Irma, the system could run the refrigerator for 10-11 hours, and the thermal insulation could keep everything cold or frozen overnight. Rather than using solar panels to charge the batteries, the system instead gets energy from the massive battery of his electric vehicle. [Jay] was out of power for 64 hours, and this system worked for him (and at a better cost) than a generator would have.

With the impact of major storms on many areas this year, we’ve been seeing a lot of interesting ways that people deal with living in areas impacted by these disasters. Besides riding through power outages, we’ve also seen the AARL step in to help, and also taken a look at how robust building codes in these areas help mitigate property damage in the first place.


The Art of Blinky Business Cards

Business cards are stuck somewhere between antiquity and convenience. On one hand, we have very convenient paperless solutions for contact swapping including Bluetooth, NFC, and just saying, “Hey, put your number into my phone, please.” On the other hand, holding something from another person is a more personal and memorable exchange. I would liken this to the difference between an eBook and a paperback. One is supremely convenient while the other is tactile. There’s a reason business cards have survived longer than the Rolodex.

Protocols and culture surrounding the exchange of cards are meant to make yourself memorable and a card which is easy to associate with you can work long after you’ve given your card away. This may seem moot if you are assigned cards when you start a new job, but personal business cards are invaluable for meeting people outside of work and you are the one to decide how wild or creative to make them.

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Monstrous USB Power Bank

At some point, cleaning out the spare parts bin — or cabinet, or garage — becomes a necessity. This is dangerous because it can induce many more project ideas and completely negate the original purpose. [Chaotic Mind], considering the pile of  batteries he’s collected over the past decade, decided that instead of throwing them out, he would recycle them into a grotesque USB power bank.

Inside the bulk of this power bank are an eye-popping 64 18650 Lithium Ion cells, mostly collected from laptop batteries, and wired in a parallel 8×8 pattern with an estimated capacity of over 100,000mAh(!!).  The gatekeeper to all this stored energy is a two-USB power bank charger board from Tindie.

Ah — but how to package all this power? The handy man’s secret weapon: duct-tape!

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Need a Night-Light?

[Scott] created an LED candle in preparation for the big mac daddy storm (storms?) coming through.  Like millions of other people in Florida, he was stuck at home with his roommates when an oncoming hurricane headed their way.  Worrying about blundering about in the dark when the power inevitably went out, they set off to gather up all of the candles they had lying around.  Realizing the monstrous pile of candles and matches looked more and more like a death wish, the decision was made to create a makeshift light out of what components they had on hand.  Now, not having access to any outside sources for parts means that you are going to have a bare bones model.

That being said, this straightforward light only takes a couple of seconds to put together.  Jury rig a couple of AA or AAA batteries up, then slap on a resistor, LED, and jumper to get that sucker running.  Wrap electrical tape around the whole thing, or even try duct tape, whatever gets the job done.  A little paper hat on top of it will diffuse the light and bada bing, bada boom, you’re all done.  Generally though, soldering directly onto a battery is not a wise idea.  So, if you want to get fancy, perhaps a better alternative is to have a battery casing as shown below.

This LED candle is a clear option if your home isn’t a micro warehouse for electronic components (apparently it is frowned upon to clog up your garage for projects), and you have limited time.  However, if you have a number of extra minutes lying around before your windows blow in, see if you can top the brightest flashlight ever made (thus far).  Continue reading “Need a Night-Light?”

A Battery-Tab Welder with Real Control Issues

Spot welding should easier than it looks. After all, it’s just a lot of current in a short time through a small space. But it’s the control that can make the difference between consistently high-quality welds and poor performance, or maybe even a fire.

Control is where [WeAreTheWatt]’s next-level battery tab spot welder shines. The fact that there’s not a microwave oven transformer to be seen is a benefit to anyone sheepish about the usual mains-powered spot welders we usually see, even those designed with safety in mind. [WeAreTheWatt] chose to power his spot welder from a high-capacity RC battery pack, but we’d bet just about any high-current source would do. The controller itself is a very sturdy looking PCB with wide traces and nicely machined brass buss bars backing up an array of MOSFETs. A microcontroller performs quite a few functions; aside from timing the pulse, it can control the energy delivered, read the resistance of the 8AWG leads for calibration purposes, and even detect bad welds. The welder normally runs off a foot switch, but it can also detect when the leads are shorted and automatically apply a pulse — perfect for high-volume production. See it in action below.

There may be bigger welders, and ones with a little more fit and finish, but this one looks like a nicely engineered solution.

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