Driving A Brushless DC Motor Sloooooooowly

Driving a brushless DC (gimbal) motor can be a pain in the transistors. [Ignas] has written up a nice article not only explaining how to do just this with an Arduino, but also explaining a little bit on how the process works. He uses a L6234 Three Phase Motor Driver, but points out that there are other ways to interface the BLDC motor with the Arduino.

warningA warning is warranted – this is not for the faint of heart. You can easily destroy your microcontroller if you’re not careful. [Ignas] added several current limiting resistors and capacitors as advised in the application note (PDF warning) to keep things safe.

Everything worked well at high speeds, but for slower speeds the motor was choppy. [Ingus] solved this riddle by changing over to a sine wave to drive the motor. Instead of making the Arduino calculate the wave, he used a look up table.

Be sure to check out his blog for full source and schematics. There is also a video demonstrating just how slow he can make the motor move below.

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Ask Hackaday: Is Amazon Echo the Future of Home Automation?

Unless you’ve been living under a case of 1 farad capacitors, you’ve heard of the Amazon Echo. Roughly the size of two cans of beans, the Echo packs quite a punch for such a small package. It’s powered by a Texas Instrument DM3725 processor riding on 256 megs of RAM and 4 gigs of SanDisk iNAND ultra flash memory. Qualcomm Atheros takes care of the WiFi and Bluetooth, and various TI chips take care of the audio codecs and amplifiers.

What’s unique about Echo is its amazing voice recognition. While the “brains” of the Echo exist somewhere on the Internets, the hardware for this circuitry is straight forward. Seven, yes seven microphones are positioned around the top of the device. They feed into four Texas Instrument 92dB SNR low-power stereo ADCs. The hardware and software make for a very capable voice recognition that works from anywhere in the room. For the output sound, two speakers are utilized – a woofer and a tweeter. They’re both powered via a TI 15 watts class D amplifier. Check out this full tear down for more details of the hardware.

circuit board

Now that we have a good idea of the hardware, we have to accept the bad news that this is a closed source device. While we’ve seen other hacks where people poll the to-do list through the unofficial API, it still leaves a lot to be desired. For instance, the wake word, or the word which signals the Echo to start listening to commands, is either “Alexa” or “Amazon”. There is no other way to change this, even though it should be easily doable in the software. It should be obvious that people will want to call it “Computer” or “Jarvis”. But do not fret my hacker friends, for I have good news!

It appears that Amazon sees (or had seen all along) that home automation is the future of the Echo. They now officially support Philips Hue and Belkin WeMo gadgets. The Belkin WeMo, which is no stranger to the hacker’s workbench, has a good handle on home automation already, making the ability to control things in your house with the Echo tantalizingly close. See the video below where I test it out. Now, if you’re not excited yet, you haven’t heard of the WeMo Maker, a device which they claim will let you “Control nearly any low-voltage electronics device“. While the WeMo Maker is not supported as of yet, it surely will be in the near future.

We know it sucks that all of this is closed source. But it sure is cool! So here’s the question: Is the Echo the future of home automation? Sure, it has its obvious flaws, and one would think home automation is not exactly Amazon’s most direct business model (they just want you to buy stuff). However, it works very well as a home automation core. Possibility better than anything out there right now – both closed and open source.

Do you think Amazon would ever open the door to letting the Echo run open source modules which allow the community to add control of just about any wireless devices? Do you think that doing so would crown Amazon the king of home automation in the years to come?

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Ask Hackaday: Quadcopter in Near Space?

Your mission, should you choose to accept it, is to send a quadcopter to near space and return it safely to the Earth. Getting it there is not that difficult. In fact, you can get pretty much anything you want to near space with a high altitude weather balloon. Getting it back on the ground in one piece is a whole other ballgame.

Why does someone need to do this? Well, it appears the ESA’s StarTiger team is taking a card out of NASA’s book and wants to use a Sky Crane to soft land a rover on Mars. But instead of using rockets to hold the crane steady in the Martian sky, they want to use…you guessed it, a quadcopter. They’re calling it the Dropter.

quadcopter on mars

At first glance, there seems to be a lot wrong with this approach. The atmosphere on Mars is about 100 times less dense than the Earth’s atmosphere at sea level. How do props operate in these conditions? Testing would need to be done of course, and the Earth’s upper atmosphere is the perfect place to carry out such testing. At 100,000 feet, the density of the stratosphere is about the same as that of the Martian surface atmosphere. AND 100,000 feet is prime high altitude balloon territory.  Not to mention the gravity on Mars is about 38% of Earth’s gravity, meaning a 5.5 pound model on Earth could accurately represent a 15 pound model on Mars.

With all of these facts taken into consideration, one can conclude that realistic testing of a scale model Martian quadcopter is within the grasp of the hacker community. We’ve seen some work on high altitude drones before, but never a quadcopter.

Now it’s your turn to do something no one has ever done before. Think you got what it takes to pull such a project off? Let us know what your approach to the challenge would be in the comments.

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Internet Knows Your Every Move Thanks to IKEA and ESP8266

[terenceang] got his feet wet with the ESP8266 WiFi module by hacking up an IKEA Molgan PIR light. The stock PIR light simply lights when motion is detected. [terenceang] added some extra functionality to it by making it send notifications to his phone as well.

The default configuration of the stock PIR light was to only work at night. This is done with a photo diode. It was removed to make it work in daylight, along with several other components. He removed a handful of current limiting resistors to disable the hi output LEDs. One was preserved as a visual indicator. The onboard voltage regulator didn’t supply enough current for the ESP8266. [terenceang] used some electronic wizardry and was able to solve the problem with an opto-coupler.

The one thing he would change is moving from battery to mains power, as expected battery life is less than two weeks.Schematics, source code and tons of great pictures are available on his blog. If you want to give it a try but need a crash course check out the recent news that the Arduino IDE works with ESP8266, or give direct programming a try.

Control Stuff With Your Muscles

[David Nghiem] has been working with circuitry designed to read signals from muscles for many years. After some bad luck with a start-up company, he didn’t give up and kept researching his idea. He has decided to share his innovations with the hacker community in the form of a wearable suit that reads muscle signals.

It turns out that when you flex a muscle, it gives off a signal called a Surface ElectroMyographic signal, or SEMG for short. [David] is using an Arduino, digital potentiometer and a bunch of op amps to read the SEMG signals. LEDs are used to display the signal levels.

The history behind [David’s] project dates back to the late twentieth century, which he eloquently points out – “Holy crap that was a long time ago”. He worked with the MIT Aero Astro Lab and the Boston University Neuromuscular Research Center where he worked on a robotic arm for astronauts. The idea being to apply an opposing force to the arm to help prevent muscle deterioration.

Be sure to check out [David’s] extensive and well documented work, along with the several videos showing his projects at various stages of completion. If this gives you the electromyography bug, check out this guide on detecting the signals and an application of the concept for robotic prosthesis.

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Get Blown Away by the Boominator

You have a greater chance of squeezing 5 amps through a 2N2222 than you do remembering the 1980s and not thinking about the legendary ‘boom box’. They could be seen perched on the shoulders of rockers and rappers alike – many sporting the Members Only or red leather jackets. The boom boxes visual characteristics can best be described as a rectangular box with two very large speakers on each end. It is no accident that The Boominator shares these features.

[Jesse van der Zouw] did a good job of showing how he created The Boominator. It has not two, but four 10 inch woofers that delivers 360 degrees of awesomeness at 115dB. The on board battery can sustain it for up to twenty hours, and the project is topped off with some blue LED rings the encircle each speaker.

We’ve seen boom boxes here before, but this is the first with some nice LED accents. Be sure to check out this build and let us know what you might have done differently.

[via Hackaday.io]

Brighten Your Day with Motion Controlled Cabinet Light

[Thomas Snow] found himself in a bit of a pickle. His kitchen lights didn’t adequately light his counter-tops. So instead of inventing a light bending device that could warp space-time enough to get the light where it needs to go, he decided to take the easy road and installed a motion controlled LED strip under the cabinets.

Now, these aren’t just any ‘ol motion control lights. Not only is [Thomas] able to turn the lights on and off with a wave of his hand, he can control the brightness as well. He’s doing the magic with an ultrasonic range sensor and PIR sensor. An ATTiny85 ties everything together to form the completed system.

The PIR sensor was incorporated because [Thomas] didn’t want to bug his pets with the 40kHz chirp from the ultrasonic sensor. So it only comes on when the PIR sensor sees your hand. Be sure to check out [Thomas’s] project for full source and schematics.

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