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!

AVR vs PIC, Round 223: Fight!

Get ready to rumble! [Thierry] made the exact same Hello-World-esque project with two microcontrollers (that are now technically produced by the same firm!) to see how the experience went.

It’s not just an LED-blinker, though. He added in a light-detection function so that it only switches on at night. It uses the Forest Mims trick of reverse-biasing the LED and waiting for it to discharge its internal capacitance. The point is, however, that it gives the chip something to do instead of simply sleeping.

Although he’s an AVR user by habit, [Thierry] finds in favor of the PIC because it’s got a lower power draw both when idling and when awake and doing some computation. This is largely because the PIC has an onboard low-power oscillator that lets it limp along at 32 kHz, but also because the chip has a lower power consumption in general. In the end, it’s probably a 10% advantage to the PIC on power.

If you’re competent with one of the two chips, but not the other, his two versions of the same code would be a great way to start familiarizing yourself with the other. We really like his isDarkerThan() function which makes extensive use of sleep modes on both chips during the LED’s discharge period. And honestly, at this level the code for the two is more similar than different.

(Oh, and did you notice [Thierry]’s use of a paper clip as a coin-cell holder? It’s a hack!)

Surprisingly, we’ve managed to avoid taking a stray bullet from the crossfire that occasionally breaks out between the PIC and AVR fans. We have covered a “shootout” before, and PIC won that round too, although it was similarly close. Will the Microchip purchase of Atmel calm the flames? Let’s find out in the comment section. We have our popcorn ready!

Minimal MQTT: Power and Privacy

In this installment of Minimal MQTT, I’m going to cover two loose ends: one on the sensor node side, and one on the MQTT server side. Specifically, I’ll tackle the NodeMCU’s sleep mode to reduce power and step you through bridging MQTT servers to get your data securely out of your home server and into “the cloud”, which is really just other people’s servers.

If you’re just stepping into this series now, you should really check out the other three posts, where I set up a server, then build up some sensor nodes, and then flesh-out a few ways to control everything from your phone or the web. That’s the coolest material, anyway. This last installment just refines what we’ve built on. Let’s go!

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Safely Creating A Li-Ion Pack From Phone Cells

[Glen], at Maker Space Newcastle Upon Tyne, is refreshingly honest. As he puts it, he’s too cheap to buy a proper battery.

He needed a 1AH battery pack to power his quadcopter controller and FPV headset, and since inadequate discharge warnings had led him to damage lithium polymer cells with these devices, he wanted his pack to use lithium-ion cells. His requirements were that the cells be as cheap, lightweight, and small as possible, so to satisfy them he turned to a stack of mobile phone cells. Nokia BL-4U cells could be had for under a pound ($1.46) including delivery, so they certainly satisfied his requirement for cheapness.

It might seem a simple procedure, to put together a battery pack, and in terms of physical wiring it certainly is. But lithium-ion cells are not simply connected together in the way dry cells are, to avoid a significant fire risk they need to have the voltage of each individual cell monitored with a special balanced charger. Thus each cell junction needs to be brought out to another connector to the charger.

[Glen]’s write-up takes the reader through all the requirements of safe lithium-ion pack construction and charging, and is a useful read for any lithium-ion newbies. If nothing else it serves as a useful reminder that mobile phone cells can be surprisingly cheap.

Lithium cells have captured our attention before here at Hackaday. Our recent Hackaday Dictionary piece provides a comprehensive primer, we’ve featured another multi-cell build, and an interesting app note from Maxim for a battery manager chip.

Nanowire Batteries Never Need Replacing

In this day and age we’re consistently surrounded with portable electronic devices. In order for them to be called “portable”, they must run on batteries. Most, if not all, use rechargeable batteries. These batteries have a finite lifespan, and will eventually need to be replaced. UCI chemist [Reginald Penner] and doctoral candidate [Mya Le Thai] have been hard at work on making rechargeable batteries that last forever.

Nanowires are great candidates for rechargeable battery technology because the wires, thousands of times thinner than a human hair, are great conductors of electricity. The problem is repeated charging and discharging makes them brittle, which causes them to eventually fail. Typically, the researchers at UCI could get 5000 to 7000 cycles in before they failed. After some trial and error, they found that if they coat a gold nanowire with an acrylic-like gel, they can get up to 200,000 charge/discharge cycles through it before failure.

We’ve seen rechargeable battery hacks before, but making a battery that never needs replacing is sure to get everyone excited.

White Oak Illuminated Bluetooth Speaker

Besides being common tools available to most hackers and makers out there, 3D printing, CNC machines, and cheap Chinese electronics have one more things in common: they were all used by [Nick] to build a bluetooth speaker system that has some interesting LED effects built into the case.

This is fresh on the heels of another hack that used similar construction methods to build a “magic” wood lamp. [Nick] takes it a step further, though. His case is precisely machined in white oak and stuffed with the latest China has to offer: a bank of lithium-ion batteries, a DC-DC converter to power the amplifier, and a Bluetooth module. After some sanding, the speakers look professional alongside the blue light features hiding behind the polycarbonate rings.

Of course you’ll want to visit the project site for all the details of how [Nick] built his speaker case. He does admit, however, that the electronics are fairly inefficient and need a little work. All in all though, it’s a very refined set of speakers that’ll look great on a bookshelf or on a beach, workshop bench, or anyplace else that you could take them.

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