Hacking The Tesla Model S Rear Drive Unit

June 6, 2016 by Gerrit Coetzee 37 Comments

[Jason Hughes] is a big fan of Tesla, he’s spent a lot of time hacking on them to figure out what fancy things the automaker is up to. His most recent adventures are with the rear drive unit of a Tesla Model S.

[Jason] has had some fame in the Tesla community before; his most publicized hack was finding the model number for Tesla’s next edition of their car hashed away in the firmware. For this project he procured a rear drive unit from… somewhere, and with some help got it onto his bench at home.

His first steps were to hook it up to some power and start sniffing the CAN bus for commands. It took him a few hours but he was able to get the motor turning. He kept working at it until he had the full set of commands. So, he hooked up circulating water to the unit for cooling, and put it through its paces (at one point the unit announced it was now traveling at 117mph).

In the end he was able to get all the features working, including generation! He even made his own board for contrl. Just listening to the motor spin up is satisfying. Videos after the break.

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Robot Moth Is Learning To Fly Like A Real Moth

June 5, 2016 by Gerrit Coetzee 24 Comments

Harvard University has had the flying robot insect market covered for a long time. However, their robot bee, while cool, was starting to bum them out. They wanted to put the battery and brain on the robocritter and have it fly around without a tether. Technology just wasn’t moving fast enough for them, so they’ve picked a different bug, this time a moth.

The Wyss Institute for Biologically Inspired Engineering at Harvard University is known for its Flying Winged Micro Air Vehicles or FWMAV. Which is a pretty good example of what happens when you let engineers name things. This FWMAV, weighs in at a hefty 3grams and has a 16mm wingspan. It also has propulsion, sensors, communication, brains, and power on board. Pretty impressive, the heaviest item is the motor!

The moth can produce 4g of thrust, and they’ve shown it capable of staying aloft once launched with a small catapult. Since they’ve proven that it can at least fly, the next steps are to figure out the dynamics of moth-based flight. Right now it stays pointed in the right direction with a very tiny tail fin like on an airplane. Real moths manage this feat with independent wing control, which the robot doesn’t have yet.

It will be a while before a we’ll see robot moths bumping into our computer monitors a night, stealing our passwords, but it’s a really cool exercise in robot miniaturization.

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It’s Time To Finally Figure Out How To Use KiCAD

June 4, 2016 by Gerrit Coetzee 72 Comments

KiCAD has been making leaps and bounds recently, especially since CERN is using it almost exclusively. However, while many things are the same, just enough of them are different from our regular CAD packages that it’s hard to get started in the new suite.

[Chris Gammell] runs Contextual Electronics, an online apprenticeship program which goes from concept to assembled electronics covering everything in between. To take the course you pay a nominal fee, but [Chris] posted a very excellent ten-part video series made during the last run of classes which you can watch without charge. The videos go through the basics of KiCAD while hitting the major points to consider when designing and manufacturing your electronics.

The project [Chris] chose is a simple circuit that blinks an LED with a 555. The first videos cover navigating KiCAD’s component schematic editor and library system. Next comes creating circuit schematics and component footprint creation. [Chris] covers PCB layout, the generation of Gerber files, and finally ordering the design from OSH Park — the purveyors of purple boards we’ve come to know and love. The series finishes up with simulating the circuit in LTSpice, ordering the parts, and finally soldering and debugging of the board. If all goes correctly you should now have a single blinking LED.

If the bright summer sun is burning your delicate skin, and you’d rather be locked inside with solder fumes, add this to your watch list now!

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How Does A Buck Converter Work Anyway?

June 4, 2016 by Gerrit Coetzee 30 Comments

[Great Scott] should win an award for quickest explanation of a buck converter. Clocking in at five and a half minutes, the video clearly shows the operating principles behind the device.

It starts off with the question, what should you do if you want to drop a voltage? Many of us know that we can dim and brighten an LED using the PWM on an Arduino, but a closer inspection with an oscilloscope still shows 5V peaks that would be dangerous to a 3.3V circuit. He then adds an inductor and diode, this keeps the current from dropping too fast, but the PWM just isn’t switching fast enough to keep the coil energized.

A small modification to the Arduino’s code, and the PWM frequency is now in the kHz range. The voltage looks pretty good on the oscilloscope, but a filter cap gets it to look nice and smooth. Lastly, he shows how when the load changes the voltage out looks different. To fix this a voltage divider feeds back the information to the Arduino, letting it change the PWM duty to match the load.

In the last minute of the video he shows how to hook up off-the-shelf switching regulators, whose support components are now completely demystified as the basic principles are understood. Video after the break.

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Pi Zero Digital Frame Kiosk Uses OTG Right

June 3, 2016 by Gerrit Coetzee 14 Comments

USB On-The-Go (OTG) is one of the fun aspects of the USB standard. There are feelings about the other aspects, but that one is alright. Regardless, [Francesco] realized one day that the £3 digital picture frames he purchased at a charity sale really didn’t care if the files on the thumb drive mysteriously changed all the time. It would just keep pulling and displaying the latest file at a blistering 0.2 frames per second. That’s right, the concept [Francesco] went after is to show changing data, even animations, with an update of one frame every five seconds!

His initial tests showed good for the concept — the Pi can easily emulate a mass storage device, feeding in data whenever the picture frame looks for it. In addition to the Pi Zero board he added an Ethernet shield, a voltage regulator, a camera, and even some infrared LEDS. We suppose there are dreams for the future.

He has been developing scripts for this rig by logging in through a VNC. A cron job runs his scripts at regular intervals, grabbing useful data and making it available as an image. For example, one script opens up the weather in Epiphany (a web browser), takes a screenshot, and saves that screenshot to the mass storage being emulated using USB OTG. The digital picture frame blissfully updates, unaware of its strange appendages. Now the real limiting factor is how much you can accomplish with your mad Bash skills.

Paraffin Oil And Water Dot Matrix Display

June 2, 2016 by Gerrit Coetzee 17 Comments

In preparation for Makerfaire, [hwhardsoft] needed to throw together some demos. So they dug deep and produced this unique display.

The display uses two synchronized peristaltic pumps to push water and red paraffin through a tube that switches back over itself in a predictable fashion. As visible in the video after the break, the pumps go at it for a few minutes producing a seemingly random pattern. The pattern coalesces at the end into a short string of text. The text is unfortunately fairly hard to read, even on a contrasting background. Perhaps an application of UV dye could help?

Once the message has been displayed, the water and paraffin drop back into the holding tank as the next message is queued up. The oil and water separate just like expected and a pump at the level of each fluid feeds it back into the system.

We were deeply puzzled at what appeared to be an Arduino mounted on a DIN rail for use in industrial settings, but then discovered that this product is what [hwhardsoft] built the demo to sell. We can see some pretty cool variations on this technique for art displays.

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Mechaduino- Closed Loop Stepper Servos For Everyone

June 1, 2016 by Gerrit Coetzee 50 Comments

Is it something in the water, or have there been a lot of really cool servo projects lately? Mechaduino is a board that sits on a regular stepper motor and turns it into a servo with a closed loop control of 0.1degree.

Whenever we post something about using cheap brushless motors for precision control, someone comments that a stepper is just a brushless motor with a lot of poles, why not just control it like one. That’s exactly what the Mechaduino does. They also hint at doing something very clever with a magnetic encoder on the board which allows them, after a calibration routine, to get the accuracy they’ve promised.

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