Category Archives: Kv

What’s the Value of a Key-Value Store?

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A database back end for your application is vital, and odds are that your database is a relational database or a "not only SQL" (NoSQL) database. Relational databases have dominated the software industry for decades, even as other technologies have radically changed around it. A relational database management system (RDBMS) should be understood as though management system is in bold type, as you must actively manage the data contained within it. Continue reading What’s the Value of a Key-Value Store?→

What’s the Value of a Key-Value Store?

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A database back end for your application is vital, and odds are that your database is a relational database or a "not only SQL" (NoSQL) database. Relational databases have dominated the software industry for decades, even as other technologies … Continue reading What’s the Value of a Key-Value Store?→

Rewound and Rewired BLDC Makes a Half-Decent Generator

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What’s the best way to turn a high-powered brushless DC motor optimized for hobby use into a decent low-RPM generator? Do you take a purely mechanical approach and slap a gearbox on the shaft? Or do you tackle the problem electrically?

The latter approach is what [GreatScott!] settled on with his BLDC rewinding and rewiring project. Having previously explored which motors have the best potential as generators, he knew the essential problem: in rough terms, hobby BLDCs are optimized for turning volts into RPMs, and not the other way around. He started with a teardown of a small motor, to …read more

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Analyzing Hobby Motors with an Oscilloscope

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We always like finding new excuses reasons to use our test equipment, so we couldn’t help but be intrigued by this tip from [Joe Mosfet]. He uses the ever-popular Rigol DS1054Z to demonstrate the differences between a handful of brushless motors when rotated by his handheld drill at a constant RPM. Not only is he able to identify a blown motor, but it allows him to visualize their specifications which can otherwise seem a bit mystifying.

One wire from each motor is used as the ground, and channels one and two are connected to the remaining wires. Despite the DS1054Z …read more

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3D-Printed Halbach Motor Part Two: Tuning, Testing

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Building your own Halbach-effect brushless DC motor is one thing. Making sure it won’t blow up in your face another matter, and watching how [Christoph Laimer] puts his motor to the test is instructive.

You’ll remember [Christoph]’s giant 3D-printed BLDC motor from a recent post where he gave the motor a quick test spin. That the motor held together under load despite not being balanced is a testament to the quality of his design and the quality of the prints. But not wishing to tempt fate, and having made a few design changes, [Christoph] wisely chose to perform a static …read more

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Hand-Wound Brushless Motors Revive Grounded Quad

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You’re happily FPVing through the wild blue yonder, dodging and jinking through the obstacles of your favorite quadcopter racing course. You get a shade too close to a branch and suddenly the picture in your goggles gets the shakes and your bird hits the dirt. Then you smell the smoke and you know what happened – a broken blade put a motor off-balance and burned out a winding in the stator.

What to do? A sensible pilot might send the quad to the healing bench for a motor replacement. But [BRADtheRipper] prefers to take the opportunity to rewind his burned-out …read more

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