MDF Omniwheel Uses No Metal Or Plastic

February 20, 2016 by Al Williams 16 Comments

What’s better than a caster? An omniwheel. These wheels are like a big wheel with little wheels at different angles that can roll in any direction. [Sonodera] built an omniwheel out of laser cut MDF. MDF–or Medium Density Fiberboard–makes up all the parts of the wheel. There’s no plastic or metal at all.

[Sonodera’s] wheel is more of a passive design like a caster. It would be possible to drive the wheel through the center in two directions, but the right-angle rollers are passive.

We’ve seen several robots with omniwheels before. In fact, this tripod-inspired robot also has passive rollers and the three-legged design takes advantage of them (the so-called Kiwi drive). Some schemes combine multi-directional wheels with conventional wheels (usually the standard wheels are in the center). There are other multi-directional wheel designs out there, including the Mecanum wheel. You can see a video of the MDF wheel in action, below.

Waiting For China To Re-Open, From Huaqiangbei

February 20, 2016 by Brandon Dunson 24 Comments

The Chinese New Year is something we keep in mind at least half of the year, and probably still don’t plan for properly. In case you’re new to the situation: The Chinese New Year celebration empties out Shenzhen of its more than 12 million residents for the better part of a month. It’s the one time of year that manufacturing sector workers (and everyone that supports that ecosystem) travels home to visit family.

For those involved in manufacturing goods in Shenzhen, this part of the year leaves us cut off from one of our vices and we count the days until our tracking numbers and order confirmations start to show signs of life. It’s an inconvenience of an entirely different nature if you are one of the lonely few that stays in the city during the holiday. [Ian] over at Dangerous Prototypes wrote a blog post from his office in Huaqiangbei which is a sub-district of Shenzhen, China to share the experience with us.

Shenzhen is uniquely a migrant-worker city, and when emptied of the factory employees there are not enough people to patronize local services like markets and restaurants so they also shut down. But an empty city offers its own interesting entertainment like wicked fireworks sessions. As always, [Ian] does a great job of sharing this peculiar part of Shenzhen culture. He also kindly points out some of the offensive offers that come through the inter-webs from desperate customers who have poorly planned around the holiday.

Good Vibrations In 3D-Printed Clay

February 20, 2016 by Elliot Williams 16 Comments

An engineer with a 3D printer wants everything to be rigid and precise. Wobble induced by flex in the z-axis feedscrews, for instance, makes telltale wavy patterns in the surface that match exactly the screw pitch. Nobody likes those, right? Certainly not an engineer!

But one man’s surface irregularity is another man’s ornamentation. The details we have are sparse, but from looking at the video (also inlined below the break) it’s clear enough: [Olivier van Herpt] and [Ricky van Broekhoven] stuck a vibrating woofer underneath the print bed of their ceramic printer, and use it to intentionally ruin their smooth surface. And they do so to great artistic effect!

We’re not suggesting that you give up entirely on your calibrations, but we do appreciate a little out-of-the-box thinking from time to time. But then our internal engineer raises his head and we wonder if they’re linking the pitch of the woofer to the feed rate of the print head. Your thoughts in the comments?

Continue reading “Good Vibrations In 3D-Printed Clay” →

Hacklet 96 – Pi Zero Contest Projects Week 3

February 20, 2016 by Adam Fabio 3 Comments

The calendar is rolling through the third week of the house that Hackaday and Adafruit built: The Raspberry Pi Zero Contest. We’re nearly at 100 entries! Each project is competing for one of 10 Raspberry Pi Zeros, and one of three $100 gift certificates to The Hackaday Store. This week on The Hacklet, we’re going to take a look at a few more contest entries.

[Phil “RzR” Coval] is trying to Port Tizen to the Raspberry Pi Zero. For those not in the know, Tizen is an open source operating system for everything. Billed as a go-to OS for everything from wearables to tablets to smartphones to in-vehicle entertainment systems, Tizen is managed by the Linux Foundation and a the Tizen Association. While Tizen works on a lot of devices, the Raspberry Pi and Pi 2 are still considered “works in progress”. Folks are having trouble just getting a pre-built binary to run. [Phil] is taking the source and porting it to the limited Pi Zero platform. So far he’s gotten the Yocto-based build to run, and the system starts to boot. Unfortunately, the Pi crashes before the boot is complete. We’re hoping [Phil] keeps at it and gets Tizen up and running on the Pi Zero!

Next up is [shlonkin] with Classroom music teaching aid. Guitar Hero has taught a generation of kids to translate flashing lights to playing notes on toy instruments. [Shlonkin] is using similar ideas to teach students how to play real music on a harmonica. The Pi Zero will control a large display model of a harmonica at the front of the classroom. Each hole will light up when that note is to be played. Harmonica’s have two notes per hole. [Shlonkin] worked around this with color. Red LEDs mean blow (exhale), and Blue LEDs mean draw (inhale). The Pi Zero can do plenty more than blink LEDs and play music, so [shlonkin] plans to have the board analyze the notes played by the students. With a bit of software magic, this teaching tool can provide real-time feedback as the students play.

[Spencer] is putting the Pi Zero to work as a $5 Graphics Card For Homebrew Z80. The Z80 in this case is RC2014, his DIY retro computer. RC2014 was built as part of the 2014 RetroChallenge. While the computer works, it only has an RS-232 serial port for communication to the outside world. Unless you have a PC running terminal software nearby, the RC2014 isn’t very useful. [Spencer] is fixing that by using the Pi Zero as a front end for his retro battle station. The Pi handles USB keyboard input, translates to serial for the RC2014, and then displays the output via HDMI or the composite video connection. The final design fits into the RC2014 backplane through a custom PCB [Spencer] created with a little help from kicad and OSHPark.

Finally we have [txdo.msk] with 8 Leaf Pi Zero Bramble. At $5 each, people are scrambling to build massively parallel supercomputers using the Raspberry Pi Zero. Sure, these aren’t practical machines, but they are a great way to learn parallel computing fundamentals. It only takes a couple of connectors to get the Pi Zero up and running. However, 8 interconnected boards quickly makes for a messy desk. [Txdo.msk] is designing a 3D printed modular case to hold each of the leaves. The leaves slip into a bramble box which keeps everything from shorting out. [Txdo.msk] has gone through several iterations already. We hope he has enough PLA stocked up to print his final design!

If you want to see more entrants to Hackaday and Adafruit’s Pi Zero contest, check out the submissions list! If you don’t see your project on that list, you don’t have to contact me, just submit it to the Pi Zero Contest! That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

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.

Continue reading “Turn Your $10 Dollar Mouse Into A Fancy $10 Dollar Mouse With CNC” →

Home-Made Solenoid Motor

February 19, 2016 by Richard Baguley 28 Comments

Want to really understand how something works? Make one yourself. That’s the approach that Reddit user [Oskarbjo] took with this neat electric motor build. He made the whole thing from scratch, using an Arduino, 3D printing, and ample quantities of wire to create a solenoid motor. This transforms the linear force of a solenoid, where a magnet is moved by a magnetic field, into rotary force. It’s rather like an internal combustion engine, but driven by electricity instead of explosions. Hopefully.

[Oskarbjo]’s engine seems to work, including a rather neat mechanism to detect the rotation of the shaft and relay that back to the controller. He hasn’t posted much detail in the build process, unfortunately, but did say that “If you’d want to build something similar I can probably help you out a bit, but half the fun is coming up with your own solutions.” Amen to that. We’ve seen a few neat solenoid motor builds, but this one wins points for starting from scratch. There is an Instagram video of the motor running after the break.

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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!