What Came First? The Chicken or the LASER?

If you’ve had a child in the last few decades, you’ve had a choice to make: if you want to know the sex of the baby ahead of time. With ultrasound you can find out or–popular these days–you can have the result sealed and have a baker create a reveal cake. Apparently, researchers at the Dresden University of Technology and the University of Leipzig wanted to do the same trick with unborn chickens.

You might wonder why anyone cares (we did). Apparently, chickens that are bred for egg laying don’t produce roosters suitable for food use. This leads to about half of the chicks being “culled” (a less ugly euphemism than gassed or shredded) and used in–among other things–animal feed. Worldwide, billions of chicks are culled each year and that’s not counting other similar situations like male turkeys and female ducks.

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Hackaday Prize Entry: Optical Experiments Using Low Cost Lasercut Parts

Experimenting with optics can be great fun and educational. Trouble is, a lot of optical components are expensive. And other support paraphernalia such as optical benches, breadboards, and rails add to the cost. [Peter Walsh] and his team are working on designing a range of low-cost, easy to build, laser cut optics bench components. These are designed to be built using commonly available materials and tools and can be used as low-cost teaching tools for high-schools, home experimenters and hacker spaces.

They have designed several types of holders for mounting parts such as lasers, lenses, slits, glass slides, cuvettes and mirrors. The holder parts are cut from ¼ inch acrylic and designed to snap fit together, making assembly easy. The holders consist of two parts. One is a circular disk with three embedded neodymium magnets, which holds the optical part. The other is the base which has three adjustment screws which let you align the optical part. The magnets allow the circular disk to snap on to the screws on the base.

A scope for improvement here would be to use ball plunger screws instead of the regular ones. The point contact between the spherical ball at the end of the screw and the magnet can offer improved alignment. A heavy, solid table with a ferrous surface such as a thick sheet of steel can be used as a bench / breadboard. Laser cut alignment rods, with embedded magnets let you set up the various parts for your experiment. There’s a Wiki where they will be documenting the various experiments that can be performed with this set. And the source files for building the parts are available from the GitHub repository.

Check out the two videos below to see how the system works.

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Don’t Take Photos of Your Arduino 101 Either, It’s Light Sensitive

Wafer level chips are cheap and very tiny, but as [Kevin Darrah] shows, vulnerable to bright light without the protective plastic casings standard on other chip packages.

We covered a similar phenomenon when the Raspberry Pi 2 came out. A user was taking photos of his Pi to document a project. Whenever his camera flash went off, it would reset the board.

[Kevin] got a new Arduino 101 board into his lab. The board has a processor from Intel, an accelerometer, and Bluetooth Low Energy out of the box while staying within the same relative price bracket as the Atmel versions. He was admiring the board, when he noticed that one of the components glittered under the light. Curious, he pulled open the schematic for the board, and found that it was the chip that switched power between the barrel jack and the USB. Not only that, it was a wafer level package.

So, he got out his camera and a laser. Sure enough, both would cause the power to drop off for as long as the package was exposed to the strong light. The Raspberry Pi foundation later wrote about this phenomenon in more detail. They say it won’t affect normal use, but if you’re going to expose your device to high energy light, simply put it inside a case or cover the chip with tape, Sugru, or a non-conductive paint to shield it.

EDIT: [Kevin] also tested it under the sun and found conditions in which it would reset. Videos after the break.

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Curiously Delightful Things Done with Lasers and Projectors

Seb Lee-Delisle has built a career around large installations that use powerful lasers and high-end projects to make people happy. It’s a dream job that came to fruition through his multi-discipline skill set, his charismatic energy, and a mindset that drives him to see how he can push the boundaries of what is possible through live interaction.

His talk at the Hackaday | Belgrade conference is about his Laser Light Synth project, but we’re glad he also takes a detour into some of the other installations he’s built. The synth itself involves some very interesting iterative design to end up with a capacitive touch audio keyboard that is lit with addressable LEDs. It controls a laser that projects shapes and images to go along with the music, which sounds great no matter who is at the keyboard thanks to some very creative coding. As the talk unfolds we also hear about his PixelPyros which is essentially a crowd-controlled laser fireworks show.

See his talk below and join us after the break for a few extra details.

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UV Photographic Printer Lets You Use Strange Chemistries

There is a family of old photographic chemistries based on iron compounds which, like the blueprint, are exposed using UV light. Ironically, the digital camera revolution which has made everything else in our photographic lives much easier, has made it harder to experiment around with these alternative methods. [David Brown] is making a UV photographic printer to change that.

[David]’s application has a lot in common with PCB printers that use a UV-sensitive resist, only [David] needs greyscale, and it might also be nice if it could work with wet paper. This makes it a more challenging project than you might think, but we like the cut of [David]’s jib.

Like some of the other UV exposer projects, [David]’s uses a rotating mirror to scan across the to-be photograph’s surface. Unlike the other ones that we’ve seen, the exposer hangs from two linear rails. Other printers move the paper underneath a stationary scanning head, which seems a mechanically simpler arrangement. We’re excited to see how this goes.

There’s a lot of interest in UV PCB printers right now. We’ve seen one made from junked CD-ROM drives on one end of the spectrum to one made by retrofitting a delta robot on the other. And don’t disregard the work done by folks interested in UV-curing 3D printers, either.

Evolving our Ideas to Build Something That Matters

When Jeffrey Brian “JB” Straubel built his first electric car in 2000, a modified 1984 Porsche 944, powered by two beefy DC motors, he did it mostly for fun and out of his own curiosity for power electronics. At that time, “EV” was already a hype among tinkerers and makers, but Straubel certainly pushed the concept to the limit. He designed his own charger, motor controller, and cooling system, capable of an estimated 288 kW (368 hp) peak power output. 20 lead-acid batteries were connected in series to power the 240 V drive train. With a 30-40 mile range the build was not only road capable but also set a world record for EV drag racing.

The “Electric Porsche 944” – by JB Straubel

The project was never meant to change the world, but with Tesla Motors, which Straubel co-founded only a few years later, the old Porsche 944 may have mattered way more than originally intended. The explosive growth between 2000 and 2010 in the laptop computer market has brought forth performance and affordable energy storage technology and made it available to other applications, such as traction batteries. However, why did energy storage have to take the detour through a bazillion laptop computers until it arrived at electro mobility?


You certainly won’t find that grail of engineering by just trying hard. Rather than feverishly hunting down the next big thing or that fix for the world’s big problems, we sometimes need to remind ourselves that even a small improvement, a new approach or just a fun build may be just the right ‘next step’. We may eventually build all the things and solve all the problems, but looking at the past, we tend to not do so by force. We are much better at evolving our ideas continuously over time. And each step on the way still matters. Let’s dig a bit deeper into this concept and see where it takes us.

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Sciencing DVD-RW Laser Diodes

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.

Laser Detector on 3D Printer Scrap
Laser Detector on 3D Printer Scrap

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!