Kicking The Tires Before You Buy: 3d Printers

February 22, 2016 by Gerrit Coetzee 103 Comments

So you’re looking to buy your first 3D printer, and your index finger is quivering over that 300 US Dollar printer on Amazon.com. Stop! You’re about to have a bad time. 3D printing has come a long way, but most 3D printers are designed through witchcraft, legends, and tall tales rather than any rigorous engineering process. I would say most 3D printer designs are either just plain bad, or designed by a team of Chinese engineers applying all their ingenuity to cost cutting. There are a few that are well designed, and there is a comparatively higher price tag attached.

I’ll start by going through some of the myths and legends that show up in 3D printers. After that I’ll go through some of the common, mostly gimmick, features that typically hinder your printer’s ability, rather than adding any useful function. Next I’ll go onto the things that will actually make your printer better. Finally, I’ll add some special consideration if you’re a beginner buying your first printer.

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Mid Century Modern Speaker From 90s Road Trash

February 21, 2016 by Gerrit Coetzee 22 Comments

[BarryAbrams] found some 90s speakers on the side of the road. At first he thought he might have made a real score, but his coworker who knows about this sort of thing (we all have one) let him know they were merely average. Undaunted, he removed the speakers from their MDF housing, fixed a small dent in one of the tweeters, and got to work.

He cut a new frame for the speakers out of plywood. He adorned the plywood box with maple and walnut from a local supplier. The box then got a coat of urethane. His skill at sign making showed in the final finish, and the wood looks very good. Our only complaint is the straight legs instead of the slightly angled and tapered ones common to mid-century modern furniture style.

The electronics are a Chinese amp and a Sonos knock-off. [Barry] only needed to control the volume and power for the speaker set. He came up with a clever 3D-printed knob and switch configuration. When the volume is turned all the way down the speaker set turns off.

The end result sounds and looks better than anything he could get for the $125 US Dollars he spent on the project. We certainly wouldn’t complain if this were a fixture in our living space.

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Turn Your $10 Dollar Mouse Into A Fancy $10 Dollar Mouse With CNC

February 19, 2016 by Gerrit Coetzee 20 Comments

We feel it’s healthy to cultivate a general desire for more neat tools. That’s just one of the reasons we like [doublecloverleaf]’s retro PC mouse. It certainly meets the requirement, the first computer mouse was wooden, and the mouse he used as the guts for this is so retro it belongs in the dollar bin at the thrift store.

To begin with, [doublecloverleaf] took a picture of the footprint of his aged, but trustworthy laser mouse. Using the photo in SolidWorks he built a model of the circuit board, and with that digitized, a mouse that suited his aesthetics around it. The final model is available on GrabCAD.

Edit: Woops, looks like we accidentally slandered a great Slovenian community CNC project. Check out the comments for more info. Original text in italics.

Next came the CNC. It looks like he’s using one of those Chinese 3040 mills that are popular right now. The electronics are no good, but if you luck out you can get a decent set of mechanics out of one. He did a two side milling operation on a wood block, using four small holes to align the gcode before each step, and then milled the bottom out of aluminum. Lastly, he milled the buttons out of aluminum as well, and turned a knurled scroll wheel on his lathe.
The end result looks exceedingly high end, and it would be a hard first guess to assume the internals were equivalent to a $10 Amazon house brand mouse.

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What Can We Learn From A Cheap Induction Cooktop?

February 19, 2016 by Gerrit Coetzee 16 Comments

Sometimes tearing down a cheap appliance is more interesting that tearing down an expensive one. A lot of the best engineering happens when cost is an issue. You may not solve the problem well, but you can solve it well enough for a discount shelf.

[openschemes] purchased a 1.8kW induction hot plate at a low price off Amazon. The reasons for the discount soon became apparent. The worst of which was a fully intolerable amount of high frequency switching noise. Wanting to know how it worked, he took it apart.

After he had it apart on his desk, he deciphered the circuit, and wrote about it clearly. As usual with extremely cheap electronics, some clever hacks were employed. The single micro-controller was used for monitoring, and generated a PWM signal that was instantly converted to DC through some filters. All the switching was done the old fashioned way, which explained why the hotplate seemed so brainless to [openschemes] when he first turned it on.

Lastly, he did some work on manually controlling the cooktop for whatever reason. The good news? He managed to figure out how to control it. Unfortunately he also destroyed his unit in the process, via a misapplication of 1200 volts. A fitting end, and we learned a lot!

Thanks [David Balfour] for the tip!

The OpenR/C Project

February 19, 2016 by Gerrit Coetzee 12 Comments

[Daniel Norée] started the OpenR/C project back in 2012 when he bought a Thing-O-Matic. In search of a project to test out his new printer, he set his sights on a remote controlled car, which as he put it,”… seemed like the perfect candidate, as it presents a lot of challenges with somewhat intricate moving parts along with the need for a certain level of precision and durability.”

After releasing his second design, the OpenR/C Truggy, he realized a community was forming around this idea, and needed a place to communicate. So, he created a Google+ group. Today, the Truggy has been downloaded over 100,000 times and the Google group has over 5,000 members. It’s a very active community of RC and 3d printing enthusiasts who are testing the limits of what a 3d printer can do.

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Adorable Matchbox Robot

February 19, 2016 by Gerrit Coetzee 9 Comments

[wattnotions] has been playing with matches, well the box they come in anyway. One day he was letting synapses fire unsupervised, and wondered if he could build a robot inside of a matchbox. His first prototype was a coin lithium battery and scrounged motors from those 3 US Dollar servos you can buy by the dozen. It scooted around just fine, but it drained the battery instantly and was a little boring.

Next, he etched a board. It had a little PIC micro, a connector for a mini LiPo, and an H bridge. It fired up just fine, and even though it drained the battery way too fast, at least it wasn’t brainless anymore. In our experience, robots tend to discard all the useful data they collect anyway, so being blind wasn’t too much of a problem.

Inspired and encouraged, with synapses gloriously undeterred, [wattnotions] set out to make a version 2. This time he ordered a board from OSHPark, made a 3D model in SketchUp, and proceeded to lock himself out from his own chip. Without a high voltage programmerhe was out of luck. The development was unfortunately put on hold.

It was fun to read along with [wattnotions] as he went on a small robot adventure. We hope he’ll complete a version 3 and have a swarm of the little fellows scooting around.

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A 3D Printed Jet Engine Appears To Function

February 15, 2016 by Gerrit Coetzee 24 Comments

[amazingdiyprojects] has been working on a 3D printable jet engine. You may remember seeing a 3D printed jet engine grace our front page back in October. That one was beautiful didn’t function. This one flips those values around. [amazingdiyprojects] seems to make a living from selling plans for his projects, so naturally most of the details of the build are hidden from us. But from what we can see in the video clips there are some really interesting solutions here.

Some of the parts appear to be hand-formed sheet metal. Others are vitamins like bearings and an electric starter. We really liked the starter mechanism, pressing in the motor to engage with a spline, or perhaps by friction, to give the starting rotation.

What really caught our attention was casting the hot parts of the printer in refractory cement using a 3D printed mold. It reminds us of the concrete lathes from World War 1. We wonder what other things could be built using this method? Flame nozzles for a foundry? A concrete tea-kettle. It’s pretty cool.

We’re interested to see how the jet engine performs and how others will improve on the concept. Video of it in action after the break.

UPDATE: [amazingdiyprojects] posted a video of the engine being disassembled.

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