Humanity Creates A Cloud Of Space Garbage, Again

April 9, 2019 by Tom Nardi 75 Comments

With the destruction of the Microsat-R reconnaissance satellite on March 27th, India became the fourth country in history to successfully hit an orbiting satellite with a surface-launched weapon. While Microsat-R was indeed a military satellite, there was no hostile intent; the spacecraft was one of India’s own, launched earlier in the year. This follows the examples of previous anti-satellite (ASAT) weapons tests performed by the United States, Russia, and China, all of which targeted domestic spacecraft.

Yet despite the long history of ASAT weapon development among space-fairing nations, India’s recent test has come under considerable scrutiny. Historically, the peak of such testing was during the 1970’s as part of the Cold War rivalry between the United States and then Soviet Union. Humanity’s utilization of space in that era was limited, and the clouds of debris created by the destruction of the target spacecraft were of limited consequence. But today, with a permanently manned outpost in low Earth orbit and rapid commercial launches, space is simply too congested to risk similar experiments. The international community has strongly condemned the recent test as irresponsible.

For their part, India believes they have the right to develop their own defensive capabilities as other nations have before them, especially in light of their increasingly active space program. Prime Minister Narendra Modi released a statement reiterating that the test was not meant to be a provocative act:

Today’s anti-satellite missile will give a new strength to the country in terms of India’s security and a vision of developed journey. I want to assure the world today that it was not directed against anybody.

India has always been against arms race in space and there has been no change in this policy. This test of today does not violate any kind of international law or treaty agreements. We want to use modern technology for the protection and welfare of 130 million [1.3 Billion] citizens of the country.

Further, the Indian Space Research Organisation (ISRO) rejects claims that the test caused any serious danger to other spacecraft. They maintain that the test was carefully orchestrated so that any debris created would renter the Earth’s atmosphere within a matter of months; an assertion that’s been met with criticism by NASA.

So was the Indian ASAT test, known as Mission Shakti, really a danger to international space interests? How does it differ from the earlier tests carried out by other countries? Perhaps most importantly, why do we seem so fascinated with blowing stuff up in space?

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Portable Pi Power Pack Makes For Petite Projects

April 9, 2019 by Brian Benchoff 24 Comments

Since the Pi Zero was released, there have been many attempts to add a power bank. Cell phone batteries are about the same size as a Pi Zero, after all, and adding a USB charging port and soldering a few wires to a Pi is easy. The PiSugar is perhaps the cutest battery pack we’ve seen for the Pi Zero, and it comes in a variety of Hats compatible with the Pi, capable of becoming a small display, a keyboard, or any other thing where a small, portable Linux machine is useful.

The core of this build is a small circuit board the size of a Pi Zero. Attached to this board is a 900mAh battery, and the entire assembly is attached to the Pi Zero with a set of two spring clips that match up with with a pair of pads on the back of the Pi. Screw both of these boards together, and you have a perfect, cableless solution to adding power to a Pi Zero.

But the PiSugar doesn’t stop there. There are also cases, for a 1.3 inch LCD top, a 2.13 inch ePaper display, an OLED display, a camera, a 4G module, and something that just presents the pins from the Pi GPIO header. This is an entire platform, and if you print these parts in white plastic, they look like tiny little sugar cubes filled to the brim with electronics and Linux goodness.

Yes, you’ve seen 3D printed Pi cases before, but nothing in the way of an entire platform that gives you a Pi Zero in an extensible platform that can fit in your pocket and looks like sweet, sweet cubes of sucrose.

Arduino Drives Seventeen Stepper Motors, Carefully

April 9, 2019 by Tom Nardi 27 Comments

It’s fair to say that building electronic gadgets is easier now than it ever has been in the past. With low-cost modular components, there’s often just a couple dozen lines of code and a few jumper wires standing between your idea and a functioning prototype. Driving stepper motors is a perfect example: you can grab a cheap controller board, hook it up to a microcontroller, and the rest is essentially just software. But recently [mechatronicsguy] wondered if even that was more hardware than was technically necessary to get the job done.

It’s not that he was intentionally looking to make things more complicated for himself, of course. His rationale was entirely economic; if you’re looking to drive a dozen or more stepper motors, even the “cheap” controllers can add up. So he started to wonder if he could skip the controller entirely and connect the stepper motor directly to the digital pins of an Arduino. Generally speaking this is a bad idea, but if you’re careful and are willing to take the risk, [mechatronicsguy] is living proof it’s possible

So what’s the trick to running a whopping seventeen individual stepper motors directly from the digital pins of an Arduino Mega? Well, to start with you’re not going to be running the beefy NEMA 17 motors like you might find in a 3D printer. [mechatronicsguy] is using the diminutive (and dirt cheap) 28BYJ-48, a light duty stepper used in many consumer products. Even with this relatively tiny motor, you need to crack open the case and cut a trace on the PCB to switch it from unipolar to bipolar.

Beyond that, you need to be careful. [mechatronicsguy] reports he’s had success running as many as ten of them at once, but realistically the fewer operating simultaneously the better. This is actually made easier due to the relatively poor specs of the 28BYJ-48 motor; its huge eleven degree step size means its not really susceptible to the same kind of slippage you’d get on a NEMA 17 when powered down. This means you can cut power to all but the actively moving motor and be fairly sure they’ll all stay where you left them.

With as popular as the 28BYJ-48 stepper is, there are several projects this “quick and dirty” method of interfacing could potentially work with. This small “barn door” star tracker is an obvious example, but we’ve also seen some very nice robotic arms built with these low-cost motors which could benefit from the technique.