Easy, Modular Alphanumeric Displays are Full of Flappy Goodness

There are plenty of ways to make large alphanumeric displays that are readable at great distances. LED signboards come to mind, as do big flat-screen LCD displays. But such displays feel a little soulless, and nothing captures the atmosphere of a busy train station like an arrivals and departures board composed of hundreds of split-flap displays.

In a bid to make these noisy but intriguing displays practical for the home-gamer, [Scott Bezek] has spent the last couple of years on a simple, modular split-flap display unit, and from the look of the video below, it’s pretty close to ready. The build log details the design process, which started with OpenSCAD and took advantage of the parametric nature of the scripting language to support any number of characters, within reason. Costs are kept low with laser-cut MDF frames and running gear, and cheap steppers provide the motion. Character cards are just PVC ID badges with vinyl letters, and a simple opto-sensor prevents missed steps and incorrect characters. The modules can be chained together into multi-character displays, and the sound is satisfyingly flappy.

[Scott] has put a lot of thought into these displays, and even if it’s not the simplest split-flap display we’ve seen, it’s really worth checking out.

Continue reading “Easy, Modular Alphanumeric Displays are Full of Flappy Goodness”

Bartop Arcade Cabinet Build Skips the Kit

An arcade cabinet is one of those things that every gamer wants at home, but few ever get. Getting a real arcade cabinet is usually expensive, and building one yourself is no small feat. There are kits you can get now which help the process along, generally taking the form of pre-cut cabinet parts, but with them comes the quiet shame of kit-building. What if your friends found out you used a kit instead of designing it yourself? The drama is almost too much to think about.

That’s how [Bogdan Berg] felt about it, at least. Not content with just getting a pre-cut cabinet kit from eBay, he decided to design and build his own bartop arcade machine in just one week: fast enough for him to fit the whole thing into his Christmas vacation. We don’t know what Christmas was like for his friends and family this year with him toiling away on this beautiful build the whole time, but we can confidently say his Christmas was awesome.

He designed the cabinet in Fusion 360, working around the limitation that the laser cutter he had access to had a work area of 24 inches by 18 inches. Some interesting design choices were made here, including going with a tab and slot construction method. While [Bogdan] admits that this aesthetic isn’t always popular, he liked how sturdy it makes the final product.

He was originally going to use plywood for the cabinet, but owing to the fact that he couldn’t find any pieces that weren’t warped locally, he switched over to MDF. Using MDF did mean he had to seal all the cut pieces with shellac before painting, but in the end he’s happy with the final lacquer paint job; even if it did take more work and materials than he anticipated.

The hardware is pretty much the standard for DIY arcades these days: a 17 inch LCD monitor he had laying around is used for the display, a two player joystick and button kit from Amazon provides the user interface, and emulation is provided by a Raspberry Pi 3 running RetroPie. A recessed door in the rear allows him to get into the machine will still maintaining a finished look on the backside.

While the size of them may vary wildly, DIY arcade cabinets are always a popular project. Whether shamelessly emblazoned with our logo or playing host to glorious LED lighting, it seems like the design of these cabinets provide as much entertainment as the games they play.

Continue reading “Bartop Arcade Cabinet Build Skips the Kit”

Homemade E-Drums Hit All The Right Notes

In our eyes, there isn’t a much higher calling for Arduinos than using them to make musical instruments. [victorh88] has elevated them to rock star status with his homemade electronic drum kit.

The kit uses an Arduino Mega because of the number of inputs [victorh88] included. It’s not quite Neil Peart-level, but it does have a kick drum, a pair of rack toms, a floor tom, a snare, a crash, a ride, and a hi-hat. With the exception of the hi-hat, all the pieces in the kit use a piezo element to detect the hit and play the appropriate sample based on [Evan Kale]’s code, which was built to turn a Rock Band controller into a MIDI drum kit. The hi-hat uses an LDR embedded in a flip-flop to properly mimic the range of an actual acoustic hi-hat. This is a good idea that we have seen before.

[victorh88] made all the drums and pads out of MDF with four layers of pet screen sandwiched in between. In theory, this kit should be able to take anything he can throw at it, including YYZ. The crash and ride cymbals are MDF with a layer of EVA foam on top. This serves two purposes: it absorbs the shock from the sticks and mutes the sound of wood against wood. After that, it was just a matter of attaching everything to a standard e-drum frame using the existing interfaces. Watch [victorh88] beat a tattoo after the break.

If you hate Arduinos but are still reading for some reason, here’s a kit made with a Pi.

Continue reading “Homemade E-Drums Hit All The Right Notes”

“Smilemachine” Helmet is a Delightful Mixture of Tech

smilemachine-square-animPart performance art and part social experiment, [mocymo]’s Smilemachine V6 helmet is as delightful as it is expressive. The helmet is made primarily from laser-cut MDF assembled around parts from a safety helmet. The display is an Android tablet with fine operation controlled by a Bluetooth mini keyboard, and the helmet cleverly makes use of the tablet’s ability to adjust the display to compensate for head tilt angle. It recently made an appearance at Maker Faire Tokyo, where the creator says the reception (especially by children) exceeded expectations.

There are several interesting things done with this device. One is the handheld controller, which is essentially a mini Bluetooth keyboard. To help allow fine control without needing to look down at the controller, the keyboard sits in a frame with some nuts and bolts used as highly tactile button extensions. By allowing the user to change the physical button layout (and setting up keyboard shortcuts on the device to match) the arrangement can be made more intuitive for the user. Some photos of this assembly are in the gallery after the break.

Geared mirrors to allow seeing out the front of the helmet.

Another interesting bit is that despite a tablet being right in front of your eyes, it is possible to see out the front of the helmet while wearing it. The solution is completely low-tech: two mirrors form a periscope whose angle can be adjusted by turning a knob on the side of the helmet.

Version 1 of the helmet was started back in 2012; this is version 6 and [mocymo] is already filling out a to-do list for refinements. The nose area is uncomfortable, the angle of periscope is slightly off and the gearing needs to be reworked, among other things. We can’t wait to see Version 7. Video and gallery are embedded below.

Continue reading ““Smilemachine” Helmet is a Delightful Mixture of Tech”

Feeding The Cat, Reinventing the Wheel

There are few projects that we see as many iterations of as the pet feeder or the plant waterer. (What is it with you people? Are you all as forgetful as we are?) Still, the fun is in the details of the implementation. Or at least that’s the case with [Emmaanuel]’s cat feeder.

The writeup is split into three parts: the worm-drive, the electronics, and the housing (here in English: worm, electronics, housing). And of course, there’s a video inlined below.

The auger and motor housing make great use of PVC pipe and 3D printing, and the dispenser unit looks quite professional. There’s not all that much to say about the electronics — an Arduino clone, an LCD, and a cheap gear motor do just about what you’d expect.

The CNC’ed case with spring-fit tabs steals the show, however. It’s made out of MDF, which doesn’t take well to screwing or glueing. With carefully routed pins and tabs that have a little spring in them, [Emmaanuel] was able to take the pieces off the mill table and just snap them together. Awesome.

Continue reading “Feeding The Cat, Reinventing the Wheel”

I’m Sorry Dave, I Only Say 28 Phrases

A few years ago, you could buy an IRIS 9000 Bluetooth speaker. Its claim to fame was that it looked like the “eye” from the HAL 9000 computer on 2001: A Space Oddessy. There’s something seductive about the idea of having a HAL eye answer your queries to Google Now or Siri. The problem is, it still sounds like Google or Siri, not like HAL.

[Badjer1] had the same problem so he decided to build his own eye. His goal wasn’t to interface with his smartphone’s virtual assistant, though. He settled on making it just be an extension cord with USB ports. As you can see in the video below, the build has HAL-style memory units, a key, and can speak phrases from the movie (well, 28 of them, at least). The key is like the one Dave used to deactivate HAL in the movie.

Continue reading “I’m Sorry Dave, I Only Say 28 Phrases”

Materials to Know: Medium Density Fiberboard

MDF is the cheapest and flattest wood you can buy at local hardware stores. It’s uniform in thickness, and easy to work with. It’s no wonder that it shows up in a lot of projects. MDF stands for Medium Density Fiberboard. It’s made by pressing materials together along with some steam, typically wood, fibers and glue. This bonds the fibers very tightly. Sometimes MDF is constructed much like plywood. Thinner layers of MDF will be made. Then those layers will be laminated together under glue and steam.The laminated MDF is not as good as the monolithic kind. It tends to tear and break out along the layers, but it’s hard to tell which kind you will get.

Proper way to attatch a fastener to MDF.
Proper way to attatch a fastener to MDF.

MDF is great, but it has a few properties to watch for. First, MDF is very weak in bending and tension. It has a Modulus of Elasticity that’s about half of plywood. Due to its structure, short interlocking fibers bound together by glue and pressure, it doesn’t take a lot to cause a crack, and then, quickly, a break. If you’d like to test this, take a sheet of MDF, cut it with a knife, flip it over, and hit the sheet right behind your cut. Chances are the MDF will split surprisingly easily right at that point.

Because of the way MDF is constructed, fasteners tend to pull out of it easily. This means that you must always make sure a fastener that sees dynamic loads (say a bearing mount) goes through the MDF to the other side into a washer and bolt. MDF also tends to compress locally after a time, so even with a washer and bolt it is possible that you will see some ovaling of the holes. If you’re going to use screws, make sure they don’t experience a lot of force, also choose ones with very large threads instead of a finer pitch. Lastly, always use a pilot hole in MDF. Any particle board can split in alarming ways. For example, if you just drive a screw into MDF, it may appear to go well at first. Then it will suddenly jump back against you. This happened because the screw is compressing the fibers in front of it, causing an upward force. The only thing pressing against that force is the top layer of laminate contacting the threads. The screw then jumps out, tearing the top layer of particle board apart.

Continue reading “Materials to Know: Medium Density Fiberboard”