Russian Hacker Multiplies Value of Boost Converter

We have a love/hate relationship with LiIon batteries. They pack all this power in such a small and light package. But for running 3.3 V devices, they’re cumbersome. They need to be stepped down a little bit when they’re fully charged at 4.2 V, but then they need to be stepped up at the end of their charge around 3.0 V.

A simple boost or buck converter can’t do both jobs, although you’d be tempted because they can be purchased for peanuts online. So [Kirich] hacked cheap boost converters into the more capable SEPIC topology, which sell for nearly 10x as much. (Google translated version here.) The bottom line? With a little desoldering, a cut trace here and an extra inductor there, and [Kirich] had a very capable circuit that would maintain a constant 3.3 V output when the input swung between 1 V and 5 V.

95aa17If SEPIC power converters are foreign to you, have a read through Maxim’s white paper on the subject. Basically, it’s a boost converter with a capacitor in the middle that lets the output voltage drop below the input voltage. An extra inductor keeps the output side of this capacitor at ground potential (on average).

If you want more detail, [Kirich] doesn’t disappoint. He tested his modifications in multiple configurations on two different models of boost converter. As you’d expect with power circuitry, layout and trace length matters, and [Kirich] took good notes. This is a great read for the frugal hacker, or anyone who’s interested in boost/buck converters.

Speaking of boost/buck circuits, we’ve got some more links for you. This video from Sparkfun’s [Pete Dokter] is worth fifteen minutes, and if you want to get your hands really dirty in the construction of such circuits, this ATtiny-based boost converter circuit is fun to play with.

Thanks [kirillre4] for the great tip!

Tour de Force Battery Hacking

Lithium-Ion batteries are finicky little beasts. They can’t be overcharged, overdischarged, overheated, or even looked at funny without bursting into flames. Inside any laptop battery pack, a battery charge controller keeps watch over all the little cells, and prevents them from getting damaged.

Of course, any “smart” device will sometimes make the wrong choices, and then it’s up to us to dig inside its brains and fix it. When [Viktor] got a perfectly good battery pack with a controller that refused to charge the batteries, he started off on what would become an epic journey into battery controllers, and the result is not just a fixed battery, but a controller-reprogramming tool, software, and three reversed controller chips so far.

devbBattery controller chips speak SMBus, and [Viktor] started out by building a USB-SMBus tool. It’s a clever use of a cheap eBay development board for a Cypress CY7C68013A USB microcontroller. Flashed with [Viktor]’s firmware and running his software on the host computer, a SMBus scan is child’s play.

The rest of the story is good old-fashioned hacking: looking for datasheets, reading industry powerpoints, taking wild guesses, googling for passwords, and toggling the no-connect pins while booting the controllers up. We’re not going to argue with results: the bq8030, R2J240, and M37512 controllers have all given up their secrets, and tools to program them have been integrated into [Viktor]’s SMBusb tool.

In short, this is one of the nicest hard-core hacks we’ve seen in a while. Kudos [Viktor]! And thanks for the SMBus tool.

How To Make Your Weller Wireless

On occasion I have encountered portable soldering irons and my impressions of them have ranged from nearly usable to total rubbish. While using a popular butane powered model and pondering if it was really any better than a copper wire and a candle a thought occurred to me. A regular old Weller station runs on 24 volts AC and performs all of its temperature regulation in a magnetically activated thermostatic fashion and all of that goodness occurs within the hand piece itself. It stood to reason that it could perform just as well with a DC source.

In this instance we are ignoring the negative effects of switching DC current over AC current on mechanical contacts. After all we are “In the Trenches” wherever we might have need for such a device. Using a couple of gel cell 12 volt 7 amp hour batteries freshly removed from a UPS I strung them up, and there you have it, a totally battery operated  iron with performance equal to that of the one at my bench.

Connecting SMPS to the Weller Iron
Connecting Power to the Weller Iron

Right at 24 volts the iron Thermocycles at the same rate as it would be while using the bench top supply for it. Just sitting under no load it cycles about every ten seconds and there was no perceptible difference in heat capacity or performance. A fully charged pair of batteries will last all day. The on state current draw from a full charge (13.5 volts on each of the batteries) yielded about a 2 amp draw. As the voltage began to decrease the current off cycle would get shorter as one would expect, but no drop in heat transfer was noticed until the batteries were well depleted and that took most of a work day.

For this instance I used the hand piece from the venerable Weller WTCPT station. For ongoing use I would not recommend this due to the use of a mechanical contact within the unit and switching of DC can reduced the life of most mechanical switches. Currently I am awaiting the arrival of some cheap eBay Hakko handpieces; I am sure they are knockoffs, but fine to experiment with a simple PWM with a feedback loop controller as the basic Hakko design also utilizes a 24 volt source. An automatic shut off timer would also be handy to avoid premature battery abuse due to a forgetful operator.

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Roomba Now Able to Hunt Arnold Schwarzenegger

Ever since the Roomba was invented, humanity has been one step closer to a Jetsons-style future with robots performing all of our tedious tasks for us. The platform is so ubiquitous and popular with the hardware hacking community that almost anything that could be put on a Roomba has been done already, with one major exception: a Roomba with heat vision. Thanks to [marcelvarallo], though, there’s now a Roomba with almost all of the capabilities of the Predator.

The Roomba isn’t just sporting an infrared camera, though. This Roomba comes fully equipped with a Raspberry Pi for wireless connectivity, audio in and out, video streaming from a webcam (and the FLiR infrared camera), and control over the motors. Everything is wired to the internal battery which allows for automatic recharging, but the impressive part of this build is that it’s all done in a non-destructive way so that the Roomba can be reverted back to a normal vacuum cleaner if the need arises.

If sweeping a just the right time the heat camera might be the key to the messy problem we discussed on Wednesday.

The only thing stopping this from hunting humans is the addition of some sort of weapons. Perhaps this sentry gun or maybe some exploding rope. And, if you don’t want your vacuum cleaner to turn into a weapon of mass destruction, maybe you could just turn yours into a DJ.

Semisolid Lithium Ion Batteries Promise Better Cars, Solar

Lithium-ion batteries make possible smaller and lighter electronics. Unfortunately, they are also costly to produce. In a conventional lithium-ion battery, many thin layers create the finished product much like filo dough in baklava. A startup company called 24M thinks they have the answer to making less expensive lithium-ion batteries: a semisolid electrode made by mixing powders and liquid to form an electrolyte goo.

Not only will the batteries be cheaper and faster to create, but the cost of the factory will be less. Currently, 24M has a pilot manufacturing line, but by 2020 they expect to scale to produce batteries that cost less than $100 per kilowatt hour (today’s costs are about $200 to $250 for conventional batteries). Under $100, the batteries become competitive with the cost of internal combustion engines, according to the article.

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Incredible Luminosity in a Portable Package

If you’ve ever wanted to bring the brightest day into the blackest night, this flashlight shall give you sight. With a 100W LED array powered by up to 32V, this thing is exceedingly bright — it clocks in at about 9000 lumens! But the best part is that all every little detail of the build was documented along the way so that we can tag along for the ride.

The all-aluminium case houses the LEDs and their heat sink, voltage regulator and display, the AD and DC adapter and converter boards and their connectors, and fans to ensure adequate ventilation. It’s powered by a custom-assembled 6400 mAh 11.1V lipo battery or DC 20V 10Amp power supply via XLR for rugged, locking connection. The battery pack connection was vacuum formed for quick-swapping, and the pack itself will sound off an alert if any of the three batteries inside the pack run out of power. A nifty added feature is the ability to check the remaining charge — especially useful if you’re looking to bring this uncommonly powerful flashlight along on camping trips or other excursions.

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Refurbishing Armored Tablets

Who can resist the insane deals on bizarre hardware that pop up on auction websites? Not [Dane Kouttron], for sure. He stumbled on Armor X7 ruggedized tablets, and had to buy a few. They’d be just perfect for datalogging in remote and/or hostile locations, if only they had better batteries and were outfitted with a GSM data modem… So [Dane] hauled out his screwdrivers and took stuff apart. What follows is a very detailed writeup of the battery management system (BMS), and a complete teardown of this interesting tablet almost as an afterthought.

First, [Dane] tried to just put a bunch more batteries into the thing, but the battery-management chip wouldn’t recognize them. For some inexplicable reason, [Dane] had the programmer for the BMS on-hand, as well as a Windows XP machine to run the antiquated software on. With the BMS firmware updated (and the manufacturer’s name changed to Dan-ger 300!) everything was good again.

Now you may not happen to have a bunch of surplus X7 ruggedized tablets lying around. Neither do we. But we can totally imagine needing to overhaul a battery system, and so it’s nice to have a peek behind the scenes in the BMS. File that away in your memory banks for when you need it. And if you need even more power, check out this writeup of reverse-engineering a Leaf battery pack. Power to the people!