Plant Biology Is A Gateway

May 23, 2018 by Brian McEvoy 7 Comments

Too many college students have been subject to teachers’ aids who think they are too clever to be stuck teaching mere underclassmen. For that reason, [The Thought Emporium] is important because he approaches learning with gusto and is always ready to learn something new himself and teach anyone who wants to learn. When he released a video about staining and observing plant samples, he avoided the biggest pitfalls often seen in college or high school labs. Instead of calling out the steps by rote, he walks us through them with useful camera angles and close-ups. Rather than just pointing at a bottle and saying, “the blue one,” he tells us what is inside and why it is essential. Instead of telling us precisely what we need to see to get a passing grade, he lets our minds wonder about what we might see and shows us examples that make the experiment seem exciting. The video can also be seen below the break.

The process of staining can be found in a biology textbook, and some people learn best by reading, but we haven’t read a manual that makes a rudimentary lab seem like the wardrobe to Narnia, so he gets credit for that. Admittedly, you have to handle a wicked sharp razor, and the chance of failure is never zero. In fact, he will tell you, the opportunities to fail are everywhere. The road to science isn’t freshly paved, it needs pavers.

If a biology lab isn’t in your personal budget, a hackerspace may have one or need one. If you are wondering where you’ve heard [The Thought Emporium]’s voice before, it is because he is fighting lactose intolerance like a hacker.

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SpaceX’s Next Giant Leap: Second Stage Recovery

May 23, 2018 by Tom Nardi 62 Comments

With the successful launch of the Bangabandhu-1 satellite on May 11th, the final version of the Falcon 9 rocket has finally become operational. Referred to as the “Block 5”, this version of the rocket is geared specifically towards reuse. The lessons learned from the recovery and reflight of earlier builds of the F9 have culminated into rocket that SpaceX hopes can go from recovery to its next flight in as few as 24 hours. If any rocket will make good on the dream of spaceflight becoming as routine as air travel, it’s going to be the Falcon 9 Block 5.

While there might still be minor tweaks and improvements made to Block 5 over the coming years, it’s safe to say that first stage recovery of the Falcon 9 has been all but perfected. What was once the fodder of campy science fiction, rockets propulsively lowering themselves down from the sky and coming to rest on spindly landing legs that popped out of the sides, is now a reality. More importantly, not only is SpaceX able to bring the towering first stage back from space reliably, they’re able to refuel it, inspect it, and send it back up without having to build a new one for each mission.

But as incredible a technical accomplishment as this is, SpaceX still isn’t recovering the entire Falcon 9 rocket. At best, they have accomplished the same type of partial reusability that the Space Shuttle demonstrated on its first flight all the way back in 1981. Granted they are doing it much faster and cheaper than it was done on the Shuttle, but it still goes against the classic airplane analogy: if you had to replace a huge chunk of the airliner every time it landed, commercial air travel would be completely impractical.

SpaceX has already started experimenting with recovering and reusing the payload fairings of the Falcon 9, and while they haven’t pulled it off yet, they’ll probably get there. That leaves only one piece of the Falcon 9 unaccounted for: the second stage. Bringing the second stage back to Earth in one piece might well be the most challenging aspect of developing the Falcon 9. But if SpaceX can do it, then they’ll have truly developed humanity’s first fully reusable rocket, capable of delivering payloads to space for little more than the cost of fuel.

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Blowing Rings With Cannons, Fogs, And Lasers

May 23, 2018 by Sven Gregori 11 Comments

In today’s healthy lifestyle oriented world, blowing smoke rings won’t impress too many people anymore. Unless of course you are [NightHawkInLight] and blow them with a vortex cannon and add lasers for visual effects. Although, his initial motivation was to build a device that could shoot lost frisbees out off the trees in his backyard disc golf course, and as avid enthusiast of shooting things through the air using a propane torch, he opted for a vortex cannon to avoid the risk of injuries shooting a projectile may cause.

With safety in mind from the beginning, [NightHawkInLight] chose to build the cannon in ways that won’t expose him or people following his footsteps to any toxic fumes. The barrel is formed by securing a roll of terrace board and simply pulling it into a cone. A series of PVC pipes and adapters build the combustion chamber that fits the terrace board barrel on its one end, and the propane torch nozzle on its other end. For easier aim and stability, he also adds a tripod mount.

Since air vortices are, well, air, and therefore not visible by themselves, they don’t offer the most visual excitement. [NightHawkInLight] solved this with a fog machine attached to the barrel, and a laser line module, which you can see for yourself in his build video after the break. In a previous vortex cannon project we could also see a more outdoorsy approach to add visibility to it.
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Automatic I2C Address Allocation For Daisy-Chained Sensors

May 23, 2018 by Jenny List 23 Comments

Many readers will be familiar with interfacing I2C peripherals. A serial line joins a string of individual I2C devices, and each of the devices has its own address on that line. In most cases when connecting a single device or multiple different ones there is no problem in ensuring that they have different addresses.

What happens though when multiple identical devices share an I2C bus? This was the problem facing [Sam Evans] at Mindtribe, and his solution is both elegant and simple. The temperature sensors he was using across multiple identical boards have three pins upon which can be set a binary address, and his challenge was to differentiate between them without the manufacturing overhead of a set of DIP switches, jumpers, or individual pull-up resistors. Through a clever combination of sense lines between the boards he was able to create a system in which the address would be set depending upon whether the board had a neighbour on one side, the other, or both. A particularly clever hack allows two side-by-side boards that have two neighbours to alternate their least significant bit, allowing four identical boards each with two sensors to be daisy-chained for a total of eight sensors with automatic address allocation.

We aren’t told what the product was in this case, however it’s irrelevant. This is a hardware hack in its purest sense, one of those which readers will take note of and remember when it is their turn to deal with a well-populated I2C bus. Of course, if this method doesn’t appeal, you can always try an LTC4316.