Panel Meter-To-Bluetooth Hack Hijacks The Display Segments

September 21, 2016 by Jenny List 23 Comments

There are a proliferation of cheap digital meter modules available online for pocket money prices. Current, voltage, frequency, or combinations thereof can all be yours for just a few dollars and a wait for shipping. Unfortunately though these meters are all self-contained units. They do not have a serial port or other interface through which you can log their readings.

This failing was not an obstacle for [Scott Harden], though. He simply added a Bluetooth interface to his combined voltage and current meter module by using an ATmega328 microcontroller to capture the signals sent to the module’s display LEDs and interpret them into readings for his Bluetooth module. He details the process of reverse engineering the meter, and his build. The result is an intriguing mess of wires with a DIP ATmega hanging on their ends. But it performs the task requested of it admirably and when mounted in a project box you would not know what lurks within.

He has made his code for the project available in his GitHub repository, we can see that this could be a valuable technique for use with other similar displays. In the video below the break he gives us a full run-down, as if his comprehensive write-up was not enough.

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Portable Workbench Crams An Entire Workspace Into One Box

September 17, 2016 by James Hobson 7 Comments

Making on the go is sometimes required in today’s busy lives, and if you find yourself traveling — say, off to university like [ZSNRA] — then a convenient solution is required. To that end, a portable electronics workbench was built in the shape of a relatively nondescript plywood box.

Plywood and foam-core are the main materials used in building this maker’s bug-out box, with two fir runners along the bottom so the case is not resting on the hinges. Inside, [ZSNRA] has packed a staggering amount of hardware which results in an 11kg suitcase.

Here goes — deep breath now: wires, solder, resistors, transistors, capacitors, diodes, clips, switches, logic chips, non-logic chips, an Arduino, ATmegas, fuses, pliers, wire strippers and cutters, angle cutters, tweezers, a 66-piece screwdriver set, a desoldering pump, 12 needle files, a hacksaw blade, a multi meter, oscilloscope, power source, four outlets built into the case(!), steel wool, a third hand, a soldering station, two handbooks, and a breadboard.

Whew.

The work surface is an ESD mat on the inside of the case’s front face that is comfortable enough to work with, though we are surprised that it doesn’t also fold out somehow to create an even larger work-space.

For an elegant — if slightly less mobile — workbench solution, check out The Tempel. Now if you’re looking for ideas on how and what to carry we still think [Kenji Larsen] has the ultimate hacking kit.

[Thanks for the tip, Zaphod! via /r/electronics]

Yet Another Inductance Measuring Scheme

September 15, 2016 by Al Williams 13 Comments

How do you measure the value of an unknown inductor? If you have an LCR bridge or meter, you are probably going to use that. If not, there are many different techniques you can use. All of them rely on the same thing my Algebra teacher Mr. Harder used to say back in the 1970’s: you have to use what you know to get what you don’t know.

[Ronald Dekker] must think the same way. He took a 50-ohm signal generator and a scope. He puts the signal output to about 20kHz and adjusts for 1V peak-to-peak on the scope. Then he puts the unknown inductor across the signal and adjusts the frequency (and only the frequency) for an output of 1/2 volt peak-to-peak.

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Build Your Own Import Variable Lab Bench Power Supply

September 12, 2016 by Gerrit Coetzee 14 Comments

Does it ever just kill you that someone in a factory somewhere got to have all the fun of assembling your bench tools? There are a lot of questionable circuit boards floating around the Internet, and they can replicate practically any section of a circuit. When it comes to putting a prototype these days you can pretty much just buy each block of your system’s overview flowchart and string them together. [GreattScott!] combines a few of these into a relatively useful variable power supply with current limiting.

Admittedly, this is more of academic exercise if your only metric for success is monetary savings. Comparable power supplies can be purchased for the same amount of local currency as the parts in this build. However, there is something to be said for making it yourself.

The core of this build is based around the LTC3780, a bit of silicon from LT that offers both buck and boost converting along with a current control mode. It’s useful for a lot of things. The here is rated for up to 130 watts of power, which makes is a decent amount of power for a bench supply.

With a few modifications, like replacing the world’s most untrustworthy potentiometers and adding a nice ABS box, the build is completed. Along the way, [GreatScott!] offers a few tricks for testing and some reminders of how not to make yourself dead when playing with electricity.

The end is a working lab bench supply project that can easily keep a hacker entertained on a lazy Sunday afternoon.

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Safely Remove Drill Chuck; Receive Motor, Gearbox, And Clutch

September 8, 2016 by Donald Papp 34 Comments

There’s a treasure trove of usefulness inside of an electric drill. [Steven Dufresne], Hackaday writer and the mad scientist behind Rimstar.org, kindly documented how to safely and reliably remove the chuck from a drill motor. You may think this is easy, but once in a while you’ll come across a drill determined to hold onto all its bits. We certainly were entertained by the lengths [Steven] went to in the video below to get a Black and Decker to give up its chuck.

An understanding of how the chuck and gearbox are connected, combined with the right tools and a bit of force, gets you a motor, gears and gearbox, and a clutch. There’s not much left in the drill after that, and you can put some or all of those components to new use — like using them for the drive system of a BB-8 Droid.

Many projects (like this walking scooter) make use of cordless drills as motor sources. Being able to skip the chuck in order to interface directly to the shaft is useful for those projects where the drill is at least a semi-permanent part of the build. Ask your friends, neighbors, and at work. Cheap cordless drills and screw guns have been around for a long time. It’s usually the batteries that go and many people have the drills lying around and will be happy to part with them knowing you’re going to do something awesome with them.

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Tour De Force Battery Hacking

September 3, 2016 by Elliot Williams 23 Comments

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.

Battery 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.

Mini Plasma Cutter

September 2, 2016 by Al Williams 13 Comments

What do you get when you combine an arc cigarette lighter and some scrap glass and metal? [NightHawkInLight] created a simple plasma cutter project along with some hot glue and a few simple tools.

If you aren’t a smoker, an arc lighter uses a high voltage spark to light the cigarette. He essentially cannibalizes it for use as a power supply. Any similar high-voltage power supply should work just as well. He also uses the same cigarette lighter power supply for an arc pen, that we covered earlier.

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