I2c Relay Expander Uses Nifty Card-Edge Connection

May 18, 2016 by 24 Comments

[Andrew Sowa] wanted to use an off-the-shelf relay board from Numato Labs. The board lacks a suitable computer interface, which meant that [Andrew] would have to build one, and its input connectors are screw terminals, which meant a lot of wiring. Undeterred, he created an i2c expansion board using an MCP23017 I/O port expander, and with a novel card-edge designed to mate with the screw terminals, solving both problems at once.
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Subsea ROV Has 6 Degrees Of Freedom + Autopilot

May 18, 2016 by 16 Comments

This is what happens when you give Norwegian engineering students half a year to develop an ROV for their class.

The team utilized 3D printing to design and print their own thruster propellers and ducts for the ROV. It’s powered by HobbyKing motors with VESC speed controllers. This allows them to get from 0.6 to 30N of thrust from each propeller at 12V. Because of this accuracy they’re able to use a PID system to do automatic pitch, roll and depth control!

The electronics are housed in a 200mm acrylic tube (15mm wall thickness) with aluminum end caps and o-rings — an exact pressure rating is not given, but the team could flood the chamber with non-conductive oil to increase that even more — they just don’t need to for tests in a swimming pool. The undersea wire connectors they use (Subconn) are rated for 700 and 600 bar!

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Navid Gornall Eats His Own Face

May 18, 2016 by 27 Comments

Navid Gornall is a creative technologist at a London advertising agency, which means that he gets to play with cool toys and make movies. That also means that he spends his every working hour trying to explain tech to non-technical audiences. Which is why he was so clearly happy to give a talk to the audience of hardware nerds at the Hackaday Belgrade conference.

After a whirlwind pastiche of the projects he’s been working on for the last year and a half, with tantalizing views of delta printers, dancing-flame grills, and strange juxtapositions of heat sinks and food products, he got down to details. What followed was half tech show-and-tell, and half peering behind the curtain at the naked advertising industry. You can read our writeup of the highlights after the video below.

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Flying With Proportional – Integral – Derivative Control

May 18, 2016 by 24 Comments

Your quad-copter is hovering nicely 100 feet north of you, its camera pointed exactly on target. The hover is doing so well all the RC transmitter controls are in the neutral position. The wind picks up a bit and now the ‘copter is 110 feet north. You adjust its position with your control stick but as you do the wind dies and you overshoot the correction. Another gust pushed it away from target in more than one direction as frustration passes your lips: ARGGGHH!! You promise yourself to get a new flight computer with position hold capability.

How do multicopters with smart controllers hold their position? They use a technique called Proportional – Integral – Derivative (PID) control. It’s a concept found in control systems of just about everything imaginable. To use PID your copter needs sensors that measure the current position and movement.

The typical sensors used for position control are a GPS receiver and an Inertial Management  Measurement Unit (IMU) made up of an accelerometer, a gyroscope, and possibly a magnetometer (compass). Altitude control would require a barometer or some other means of measuring height above ground. Using sensor fusion techniques to combine the raw data, a computer can determine the position, movement, and altitude of the multicopter. But calculating corrections that will be just right, without over or undershooting the goal, is where PID comes into play. Continue reading “Flying With Proportional – Integral – Derivative Control” →

Using Missile Tech To See Like Predator

May 18, 2016 by 30 Comments

[Artem Litvinovich] wanted to see by heat vision like in the Predator movies. He not only succeeded but went on to see in color, medium-wave IR, short-wave IR, and ultraviolet using a very unique approach since his effort began back in 2009.

He started with a box based on the basic pinhole camera concept. In the box is a physical X-Y digitizer moving a photodiode to collect the thousands of points needed to create a picture. First all he got, due to the high signal amplification, was the 60 cycle hum that permeates our lives. A Faraday cage around the box helped but metal foil around the sensor and amplifier finally eliminated the noise. Now he had pictures in the near infrared (NIR). Continue reading “Using Missile Tech To See Like Predator” →

The Art And Science Of Bending Sheet Metal

May 18, 2016 by 50 Comments

A motor mount. A sturdy enclosure. A 43.7° bracket. The average hack requires at least one angled metal part, and the best tool to make one is still the good ol’ press brake. Bending parts requires a few extra thoughts in the design and layout of the flat patterns, so if you want to know about bend allowances, bend deduction and how to bend accurate parts even without a press, read on.

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Hacking R/C Brushless Motor Controllers For Use In Big Robots

May 18, 2016 by 15 Comments

[professor churlz] wrote in to let us know his results with modifying radio control ESCs (Electronic Speed Controllers) for use in a large (250lb range) BattleBot’s drivetrain. It’s a very long and involved build log entry that is chock-full of details and background.

If you want something spinning hard and fast, brushless is where it’s at. Brushless motors offer much better power-to-weight ratios compared to brushed DC motors, but some applications – like a large robot’s drivetrain – are less straightforward than others. One of the biggest issues is control. Inexpensive brushless motors are promising, but as [professor churlz] puts it, “hobby motor control equipment is not well suited for the task. Usually created for model airplanes, the controllers are lightly built, rated to an inch of the components’ lives using unrealistic methods, and usually do not feature reversing or the ability to maintain torque at low speeds and near-stall conditions, which is where DC motors shine.” Taking into account the inertia of a 243 lb robot is a factor as well – the controller and motor want to start moving immediately, but the heavy robot on the other side of it doesn’t. The answer was a mixture of hardware and firmware tweaking with a lot of testing.

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