Hackaday Prize Entry: Waterspace, A Floating Hackerspace Lab

June 9, 2016 by Elliot Williams 7 Comments

It’s a boat! It’s a hackerspace! It’s a DIY research platform and an art gallery! It’s Boat Lab!

[Andrew Quitmeyer] lead a project in the Philippines that was nominally charged with making an art and technology space. After a few days brainstorming, four groups formed and came up with projects as wide-ranging as a water-jet video screen and a marine biology lab. What did they have in common? They were all going to take place on a floating raft hackerspace in a beautiful body of water in Manila.

This is a really crazy meta-project, and any of the sub-projects would be worth their own blog post. Even more so is the idea itself — building a floating hackerspace is just cool. The write-up on Hackaday.io linked above is pretty comprehensive, and the “Waterspace” book talks a bit more about the overarching process. Boat Lab is a great entry into the Citizen Science phase of the Hackaday Prize 2016.

But we also love the idea of hackerspaces in non-traditional places. The Cairo Hackerspace is working on a van-based space. And now we’ve seen a boat. What other mobile hackerspace solutions are out there? We’d love to hear!

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DIY Vacuum Chamber Proves Thermodynamics Professor Isn’t Making It All Up

April 26, 2016 by Gerrit Coetzee 34 Comments

[Mr_GreenCoat] is studying engineering. His thermodynamics teacher agreed with the stance that engineering is best learned through experimentation, and tasked [Mr_GreenCoat]’s group with the construction of a vacuum chamber to prove that the boiling point of a liquid goes down with the pressure it is exposed to.

His group used black PVC pipe to construct their chamber. They used an air compressor to generate the vacuum. The lid is a sheet of lexan with a silicone disk. We’ve covered these sorts of designs before. Since a vacuum chamber is at max going to suffer 14.9 ish psi distributed load on the outside there’s no real worry of their design going too horribly wrong.

The interesting part of the build is the hardware and software built to boil the water and log the temperatures and pressures. Science isn’t done until something is written down after all. They have a power resistor and a temperature probe inside of the chamber. The temperature over time is logged using an Arduino and a bit of processing code.

In the end their experiment matched what they had been learning in class. The current laws of thermodynamics are still in effect — all is right in the universe — and these poor students can probably save some money and get along with an old edition of the textbook. Video after the break.

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Sciencing DVD-RW Laser Diodes

April 18, 2016 by Elliot Williams 16 Comments

If you’ve played around with laser diodes that you’ve scavenged from old equipment, you know that it can be a hit-or-miss proposition. (And if you haven’t, what are you waiting for?) Besides the real risk of killing the diode on extraction by either overheating it or zapping it with static electricity, there’s always the question of how much current to put into the thing.

[DeepSOIC] decided to answer the latter question — with science! — for a DVD-burner laser that he’s got. His apparatus is both low-tech and absolutely brilliant, and it looks like he’s getting good data. So let’s have a peek.

First up is the detector, which is nothing more than a photodiode, 100k ohm load resistor, and a big capacitor for a power supply. We’d use a coin-cell battery, but given how low the discharge currents are, the cap makes a great rechargeable alternative. The output of the photo diode goes straight into the scope probe.

He then points the photodiode at the laser spot (on a keyboard?) and pulses the laser by charging up a capacitor and discharging it through the laser and a resistor to limit total current. The instantaneous current through the laser diode is also measured on the scope. Plotting both the current drawn and the measured brightness from the photodiode gives him an L/I curve — “lumens” versus current.

Look on the curve for where it stops being a straight line, slightly before the wiggles set in. That’s about the maximum continuous operating current. It’s good practice to de-rate that to 90% just to be on the safe side. Here it looks like the maximum current is 280 mA, so you probably shouldn’t run above 250 mA for a long time. If the diode’s body gets hot, heatsink it.

If you want to know everything about lasers in general, and diode lasers in particular, you can’t beat Sam’s Laser FAQ. We love [DeepSOIC]’s testing rig, though, and would love to see the schematic of his test driver. We’ve used “Sam’s Laser Diode Test Supply 1” for years, and we love it, but a pulsed laser tester would be a cool addition to the lab.

What to do with your junk DVD-ROM laser? Use the other leftover parts to make a CNC engraver? But we don’t need to tell you what to do with lasers. Just don’t look into the beam with your remaining good eye!

Experiments With A Bowden Extruder Filament Force Sensor

February 9, 2016 by Gerrit Coetzee 20 Comments

We were excited to learn that someone had started working with force sensors on filament extruders, especially after we posted about a recent development in filament thickness sensors.

[airtripper] primarily uses a Bowden extruder, and wanted to be a little more scientific in his 3D printing efforts. So he purchased a force sensor off eBay and modified his extruder design to fit it. Once installed he could see exactly how different temperatures, retraction rates, speed, etc. resulted in different forces on the extruder. He used this information to tune his printer just a bit better.

More interesting, [airtripper] used his new sensor to validate the powers of various extruder gears. These are the gears that actually transfer the driving force of the stepper to the filament itself. He tested some of the common drive gears, and proved that the Mk8 gear slipped the least and provided the most constant force. We love to see this kind of science in the 3D printing community — let’s see if someone can replicate his findings.

VHS-Tape-Plasma Mirror Drives Tiny Particle Accelerator

February 9, 2016 by Elliot Williams 28 Comments

When you think of a particle accelerator, you’re probably thinking of tens of kilometers of tube buried underground, at high vacuum, that uses precisely timed electromagnetic fields to push charged particles like electrons up to amazing speeds (and energies). However, it’s also possible to accelerate electrons in other ways, and lasers are a good bet. Although a laser-based particle accelerator can push electrons very effectively for a few centimeters, they top out at a relatively low maximum “speed” of a couple billion electron-volts, as opposed to the trillions of eV that you can get out of a really big traditional accelerator.

If only you could repeat the laser trick again, “hitting” the already-moving electrons from behind with another beam, you could boost them up to even higher energies. Doing so would take something like a one-way mirror that lets the electrons pass through, but that you could then bounce a laser beam off of. In a fantastic mixture of science and mother-of-invention-style hacking, these scientists from Lawrence Berkeley National Labs use plain-old VHS tape to make plasma mirrors to do just that. Why VHS tape? Because it’s cheap, flexible, and easy to move through the apparatus at high speeds.

The device works like this: a first laser beam passes through a jet of ionized gas and pulls some electrons with it. These electrons are then focused into a beam and pass through some (moving) VHS tape. The electrons punch a hole through the tape. In their wake they leave a hot plasma of mid-90s TV shows you never got around to watching. The second laser beam is then bounced off this plasma mirror and further accelerates the electron beam from behind. In principle, you could repeat this second stage enough times to build up the energy you needed, but for now the crew is working to characterize their single-stage beam. Getting the timing right on the second-stage beam is, naturally, non-trivial.

Anyone who has spent some time in a science lab knows that there are millions of these tiny get-it-done-quick hacks behind the scenes, but it’s nice to see one take center stage as well. If you’ve got stories of great lab hacks that you’d like to see us cover, post up in the comments!

Thanks [Bruce] for the tip, via Science Daily.

The Toy Maker

January 22, 2016 by Anool Mahidharia 8 Comments

A large part of the world still educates their kids using a system that’s completely antiquated. Personal choices and interests don’t matter, and learning by rote is the norm. Government schooling is woefully inadequate and the teachers are just not equipped, or trained, to be able to impart useful education. [Arvind Gupta], a science educator, is trying to change this by teaching kids how to build toys. His YouTube channel on Toys for Science and Math Education has almost 100,000 subscribers and over 44 million views. It’s awesome.

[Arvind] graduated from one of the finest engineering schools in India, the Indian Institute of Technology in Kanpur, and joined the TATA conglomerate at their heavy-vehicles plant helping build trucks. It didn’t take him long to realize that he wasn’t cut out to be building trucks. So he took a year off and enrolled in a village science program which was working towards changing the education system. At the weekly village bazaar, he came across interesting pieces of arts and crafts that the villagers were selling. A piece of rubber tubing, used as the core of the valve in bicycle tubes, caught his eye. He bought a length and a couple of matchboxes, and created what he calls “matchstick Meccano”.

This was in the 1970’s. Since then, he has been travelling all over India getting children to learn by building fun toys. The toys he designs are made from commonly available raw material and can be easily built with minimum resources. These ingenious DIY toys and activities help make maths and science education fun and interesting for children at all levels of schooling. All of his work is shared in the spirit of open source and available via his website and YouTube channels. A large body of his work has been translated in to almost 20 languages and you are welcome to help add to that list by dubbing the videos.

Check out the INK Conference video below where he shares his passion for education and shows simple yet entertaining and well-designed toys built from trash and recycled materials.

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Drawn In By The Siren’s Song

January 21, 2016 by Elliot Williams 31 Comments

When I say “siren” what do you think of? Ambulances? Air raids? Sigh. I was afraid you were going to say that. We’ve got work to do.

You see, the siren played an important role in physics and mathematics about 150 years ago. Through the first half of the 1900s, this fine apparatus was trivialized, used for its pure noise-making abilities. During the World Wars, the siren became associated with air raids and bomb shelters: a far cry from its romantic origins. In this article, we’re going to take the siren back for the Muses. I want you to see the siren in a new light: as a fundamental scientific experiment, a musical instrument, and in the end, as a great DIY project — this is Hackaday after all.

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