[Davide Gironi] shows us how to implement a sensorless brushless DC motor controller (sensorless BLDC) using an ATmega8 microcontroller. In order to control a BLDC motor you need to know its rotational sequence position and speed so you can calculate and apply the correct current phase sequence to the motor windings at just the right time.
Simply said, sensorless BLDC means you’re not using a purpose built sensor to determine the motor’s position and speed, however, you are sensing the motor’s sequence position using the back EMF signal coming from one of motor’s coils that is not currently receiving power. When this back EMF signal crosses zero voltage a microcontroller can calculate the rotational speed and when to switch to the next power sequence. This technique is not good for position control motors but is great for continuous motors like computer fans and drives were the slightly reduced wiring costs make this type of BLDC control favored.
If you want to build a BLDC controller we recommend starting with [Davide’s] last project on sensor controlled BLDC motors. You can also checkout these interactive demonstrations for more understanding on the different BLDC configurations.
Follow along after the break to watch the video demonstration of [Davide’s] sensorless BLDC controller controlling a motor from CD-ROM drive.
Continue reading “Build a Sensorless Brushless DC Motor Controller”
Turntable photography has seen a rise in popularity driven by online shopping. If you can’t hold it in your hand at least you can see what it looks like from all angles. From the still image, [Petteri Aimonen’s] roll-your-own turntable looks great. It’s completely enclosed and has a very nice paint job. But when you see it in action it appears to suffer from a stutter.
Continue reading “Fail of the Week: Photography Turntable”
You know when you see something like this it’s just going to be awesome, and we weren’t disappointed by our first impression. [Davide Gironi] built a brushless motor controller from the ground up using an ATmega8 as the brain. If you want to understand every aspect of a subject this is how to do it. Lucky for us he explains what each portion of the prototype does.
Brushless motors have no brushes in them (duh). But what does that really mean? In order to spin the motor a very carefully crafted signal is sent through the motor coils in the stationary portion (called the stator), producing a magnetic field that pushes against permanent magnets in the rotor. A big part of crafting that signal is knowing the position of the rotor. This is often accomplished with Hall Effect sensors, but can also be performed without them by measuring the back EMF in the coils not currently being driven. The AVR-GCC compatible library which [Davide] put together can be tweaked to work with either setup.
Get a good look at the system in action after the break.
Continue reading “Building a brushless motor controller around an ATmega chip”
Here’s [Tom Parker] showing off a brushless motor gimbal stabilizer for his GoPro camera. We saw a similar project a couple of weeks back that featured a 3d printed quadcopter mount. This offering is meant to be held in your hands. It keeps the subject in frame even if the cameraman’s hands pitch and roll (we figured aeronautical terms were best here). This image shows him demonstrating a level camera as he quickly rolls the frame from one side to the other. It doesn’t compensate for yaw, which is something he may change in the next iteration. We already like the results he’s getting with it.
About 3:15 into the video demo below we get a very quick description of the build itself. He started it as a project at University. Fabrication included work on a 3D printer, laser cutter, and vacuum forming machine. The grips are bicycle handlebar components. To overcome the stabilization system the operator has access to a joystick. Without this you’d never be able to aim the camera up or down because of auto-leveling.
Continue reading “Showing off a high-performance brushless motor camera gimbal”
It’s been a long time coming, but efforts to create Open Source brushless motor controller are finally paying off.
The Open-BLDC project aims to create an open source motor controller for the brushless motors usually found in remote control airplanes, helicopters, and quadcopters. Normally, these motor controllers – usually called electronic speed controllers – can’t supply more than a few dozen amps, and are usually only controllable via a servo signal.
The Open-BLDC goes far beyond the capabilities of off-the-shelf ESCs with up to 200 amps of output, TTL level serial input, and the ability to use regenerative breaking.
While the Open-BLDC project is far from complete, the team working on the hardware hopes to add I2C, CAN, and PPM interfaces, along with speed and torque control.
There is no word on when, or even if, the Open-BLDC will ever be available for sale, but with the features it has it would be welcomed by just about any builder constructing a gigantic RC vehicle.
Ever wonder what CPU dev boards look like?
In the realm of highly confidential hardware, it doesn’t get much more secret than upcoming CPUs coming out of Intel. Somehow, a few CPU dev boards wound up on eBay, and [Leon] was cool enough to save all the pictures (Polish, Google translation, or translate in the sidebar). There are a few ongoing auctions right now, but we’d settle for this LGA 1156 breakout board. So cool.
No, we’re not linking directly to the free stuff
TI is giving away a brushless motor controller powered by a Stellaris ARM processor. [Chris] says he’s ordering one to figure out how to make a Stellaris dev board out of the giveaway. This controller is designed for e-bikes, so at the very least we see a few ginormous UAVs in someone’s future.
More rocket stuff!
One of [Bill]’s older hacks was taking a CVS disposable digital camera (remember that?) and stuffing it into the nose code of an Estes D-powered rocket. There’s a ton of videos of the flights [Bill] put up on YouTube.
On another note, [CyberPunk] built a half-scale model of a swing-wing rocket launched glider (pics: 1, 2, 3, 4). He’s currently building the full-size version capable of carrying RC and video gear and wants some feedback.
So, CAD on a tablet?
[spuder] caught wind of a tablet-based engineering notebook a few people are working on. They’re looking for some feedback on their demo video. We think it’s cool – especially the ability to share stuff between devices – but CAD on a tablet makes us extremely skeptical. Tell them what you think; we’d love to see this make it to our phone.
Now if they only made one for editing WordPress posts….
Test-driven development just got cooler. Here’s a Tamagotchi for Eclipse that you ‘feed’ by going from red to green and refactoring your code. Be careful, because having the same code test as red twice will kill your little code ninja.
And now I’ll rant about you.
A few days ago, I posted [Becky Stern]’s light-up handlebars project, and one comment surprised me. Who says guys can’t sew? It’s time to confront the gender roles that show up whenever sewing is used in a project. I’m doing a tutorial on how to sew a parachute, but I need your help. It’ll be a two-parter: one on how to actually use a sewing machine, and another for how to make a ‘chute. Is there anything else you’d like to see?
In the quest for a diy laser cutter made from DVD burner parts (that hack’s still in the works) this guy ended up with a junk box full of optical-drive leftovers. He put some of that surplus to good use by building this stroboscope. As the media spins, the white LED just out of focus in the foreground strobes to freeze the little black figure in the same place. The effect, as seen in the video after the break, is a dancing figure created by the optical illusion.
This is the same concept as that amazing 3D rowing skeleton build, but scaled down greatly. Each of the silhouettes seen above are slightly different, showing one pose that makes up a frame of the overall animation. They’re laser cut, but some careful paper-craft could probably accomplish the same thing. Assuming you could keep them from warping when spinning at high speeds.
Continue reading “Stroboscope project uses optical drive motor and Arduino”