[Fran] & [Bil]‘s Dinosaur Den

DinosaurI suppose I can take credit for introducing the super awesome [Fran Blanche] to Hackaday’s very own crotchety old man and Commodore refugee [Bil Herd]. I therefore take complete responsibility for [Fran] and [Bil]‘s Dinosaur Den, the new YouTube series they’re working on.

The highlight of this week’s episode is a very vintage Rubicon mirror galvanometer. This was one of the first ways to accurately measure voltage, and works kind of like a normal panel meter on steroids. In your bone stock panel meter, a small coil moves a needle to display whatever you’re measuring. In a mirror galvanometer, a coil twists a wire that is connected to a mirror. By shining a light on this mirror and having the reflected beam bounce around several other mirrors, the angle of the mirror controlled by the coil is greatly exaggerated, making for a very, very accurate measurement. It’s so sensitive the output of a lemon battery is off the scale, all from a time earlier than the two dinosaurs showing this tech off. Neat stuff.

One last thing. Because [Bil] and [Fran] are far too proud to sink to the level of so many YouTube channels, here’s the requisite, “like comment and subscribe” pitch you won’t hear them say. Oh, [Bil] knows the audio is screwed up in places. Be sure to comment on that.

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Laser Spirograph exhibit repair and upgrade

[Bill Porter] continues finding ways to help out at the local museum. This time he’s plying his skills to fix a twenty-year-old exhibit that has been broken for some time. It’s a laser spirograph which had some parts way past their life expectancy.

He started by removing all of the electronics from the cabinet for further study in his lair. He examined the signal generator which when scoped seemed to be putting out some very nice sine waves as it should. From there he moved on to the galvos which tested way off of spec and turned out to be the offending elements.

A bit of searching around the interwebs and [Bill] figured out an upgrade plan for the older parts. But since he was at it, why not add some features at the same time? He rolled in a port so that just a bit of additional circuitry added later will allow shapes and logos to be drawn on the screen. One of his inspirations for this functionality came from another DIY laser projector project.

Take a look at the results of the repair process in the clip after the break.

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Laser light show features full XY control via homemade galvanometers

laser_light_show

[Rich] over at NothingLabs has put together a really cool laser light show that you really must see in an effort to win a laser cutter from Instructables.

His walkthrough discusses the mechanics of laser light shows – specifically how galvanometers are typically used to precisely aim mirrors in order to draw images and write text. Commercial galvanometers tend to be pretty expensive, so he opted to build his own, using relatively cheap and easy to find parts.

The galvanometers were constructed using a pair of old speaker woofers, a few Lego bricks, and some acrylic mirror squares. The mirrors were mounted on the speakers, which were then wired to an Arduino. He removed the batteries from a cheap red laser pointer and permanently wired it to the Arduino, which it now uses as a pulsed power source. Once he had everything built, he positioned the laser using a fog machine for guidance.

As you can see in the video below, the laser show is quite impressive. His homemade galvos provide a somewhat rough quality to the final projected image, and we like that a lot. It looks almost as if all of the text and images were hand drawn, which is a pretty cool effect.

Just as [Rich] mentions, we hope to see some cool hacks based off his work in the future.

If you are interested in some of our previous laser features, check these out.

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Another home-built laser projector

[Jarrod] sent us a link to this home-built laser projector after seeing a different projector that we featured yesterday. This system is fundamentally different. [ChaN], who finished the project several years ago, didn’t use a loudspeaker to move the mirrors, but instead build his own closed-loop Galvanometers. Two of these are controlled by an ATmega64 to produce incredibly clean and accurate vector images. It’s not just the images that are impressive, his hardware is laid-out with skill and forethought that make hiding it in a case a sacrilege.