little-hands-01

I’ve been prototyping a little helping hands thing using some 3D printed parts and miscellaneous hardware, mostly #8-32 nuts and bolts, and a few springs.

little-arm-model

The 3D part is pretty simple, a cube with two holes. It’s based on my Camera Accessory Mounting System (CAMS).

little-hands-00

First version… still figuring out how to connect everything…

little-hands-02

Springs for tension were added, but I might try using small wingnuts to adjust tension as well…

little-hands-03

Tiny zip ties hold the alligator clips in place. They can still rotate freely and are somewhat tight…

little-hands-04

Hard to see in this one, but I stacked two blocks on top of each other to allow rotation in both directions. I’ll keep working on this to see where it goes.

press-knob-model

You may remember that I recently printed a press. While the press works quite well, the one thing I didn’t like about it was the fact that I needed a screwdriver to adjust the tension. That was a quick fix though. You see, I am not a newbie when it comes to knobs.

I had one other issue when assembling my press. While it calls for M5 bolts, I only had M3 and M6 on hand, so I did what any Imperialist would do, and used non-Metric hardware. A #6-32 bolt is smaller than a 5mm bolt, but it’ll do.

You can see above the quick model I made in OpenSCAD. The idea was to built a knob in two parts around the head of the bolt. A nut tight against it would keep it from spinning loose. (We just need to finger tighten it anyway, not torque it down hard.)

press-knob-01

Here is out bolt, nut, and two printed parts ready for assembly.

press-knob-02

We put the bolt through the hole in the bottom. It needs to be screwed in as it’s meant to fit tight to give it a little more “bite” into the plastic.

press-knob-03

There! Screwed in all the way. (Not pictured: the power screwdriver I used to drive it in all the way.)

press-knob-04

Now we put the nut on. You can spin this all the way to the end so it’s up against the plastic.

press-knob-05

Once the nut is at the end I hold it with some pliers and gently tighten the screw by hand. (Not pictured: screwdriver I used to tighten the bolt.)

press-knob-06

Now we snap the top part in place and that’s about it. I was pleased that both the Prusa i3 MK3 at work and my Monoprice Maker Select at home did a great job of printing these parts and they fit together perfectly.

press-knob-07

That’s it! Tiny knob is assembled. That was pretty easy, and it works quite well. I am pleased.

press-knob-08

In my mind, the beauty of a 3D printer (like any tool) is that it can help you solve problems. This may not be world changing, but the fact that I can solve a problem by making a computer drawing of an object and then telling a machine to “print out” that object is still some sort of magic. But as the saying goes “Any sufficiently advanced technology is indistinguishable from magic.” So, yeah…

sleepy-noise-machine

Now that summer is over and the cold months have arrived we no longer sleep with fans running, but that means we sleep without the sound of fan running, and who can sleep with all that quiet?

The wife asked if I could make something that sounded like a fan, which if you know me, is right up my alley. I grabbed a Raspberry Pi Zero and got to work. I found an audio clip of an oscillating fan (wow, there are tons of fan videos on YouTube!) and dropped it onto an SD card with Raspbian and mpg123 and had something working.

The Raspberry Pi Zero has no built-in audio output so in the past I’ve tried using a USB audio dongle, but the one I tested failed miserably in The Sonic Titan so I decided to go a different route. I used a 1080P HDMI Male VGA Audio Video Converter Adapter Cable for PC Laptop PS3 Xbox I got from eBay and then sent the audio out via HDMI so it would go to the adapter. I also needed a Mini HDMI adapter for that to plug into. It works fine, and I’ve not seen the same audio problems I did with the USB dongle.

As you can see from the photo I used a custom enclosure designed by SparkFun and modified with a stabby knife. ;)

I also used a set of powered speakers, and a dual USB power supply from Monoprice. This was hacked together rather quickly, but it all works quite well. We just plug it in before bedtime and within 30 seconds we’ve got our noise. (It also helps drown out the sound of my cat trying to wake us up at 6am.)

The thing I find most amusing about this project is that even though the Raspberry Pi Zero is a “$5 computer” it comes out to almost $30 when I add in the power supply, SD card, speakers, and HDMI audio adapter. Still, I think it’s a better option than running a full desktop computer or laptop with white noise all night. (Which apparently some people do. I’ve also heard that an old phone or tablet is a good option.)

The thing I like most about “Sleepy Noise Machine” is that is was something I could easily slap together with existing parts I had around the house. I mean, you can buy a white noise machine, but why bother when you can make your own?

roof-rack-05

I’ve come to love my Honda Element more than any previous car I’ve owned. The fact that I can pull out the back seats and use it to haul all sorts of things is awesome, but sometimes things still don’t fit, and need to go on the roof. The one advantage my Honda CR-V had was a roof rack, but luckily the Element was designed with a roof rack option in mind, and a DIY version is pretty simple.

template-01

This forum post got me started in the right direction, and gave me a template to use. There were also a few useful YouTube videos on DIY roof racks that helped a bit…

template-02

I used the PDF template to create my own template in Inkscape and then printed it on paper, which I found to be less than ideal in getting the holes precisely lined up, so I did what I often do…

template-03

I turned to 3D printing. I took the SVG file and exported it to a DXF that I could pull into OpenSCAD and extruded into a 2.5D shape. From there I printed a nice (solid) template that I could use to drill the holes for the pieces that would hold up the rack.

roof-rack-03

The parts that hold up the rack are some scrap pieces of HDPE plastic, which is very solid and resistant to wear from the elements. The template worked great (with a drill press) for making the needed holes. There’s a 6mm bolt that holds everything in place. Yeah, I ended up just using one bolt instead of three on each piece, so in the end the template didn’t matter as much.

I didn’t use stainless steel bolts, so I expect they may rust out, and I might replace them. The main reason was I bought a bunch of bolts from Bolt Depot in various lengths because I didn’t know which I would use. Now that I know the length I should probably replace them. I also used Aluminum washers which are left over from using a hole saw to drill out button holes from guitar pedal enclosures. (Long story!)

roof-rack-01

The rack itself was just some square steel tube I got from Speedy Metals. It’s 1-1/4″ SQ x 1.084″ ID x .083″ Wall, BTW. (I ended up painting the tube black with an enamel paint, which was supposed to stand up to the elements but has done a terrible job and the metal has rusted quite a bit since these photos were taken.) I’ve been told grill paint or marine paint might work better. At this point I’d need to pull everything apart and sand off the rust if I want to make things look better. (Which means I probably won’t.) The other nice thing about getting the square tube from Speed Metals was that I was able to just have them cut them to length, so I didn’t need to cut the metal precisely.

roof-rack-04

The other piece for the roof rack are the end pieces. Yes, they are green instead of orange or black, but that’s due to the filament I had loaded into the 3D printer at the time…

tube-end-01

Amazingly enough, they are printed in PLA and have held up quite well through one winter and one summer. They didn’t melt in the summer or get destroyed by the cold and wetness of winter.

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They are not held in place as securely as I’d like, and are easy to remove, but they’ve stayed in place without falling out for over a year now. I should really print some replacements in another color… though it does make it easy to spot my car when other orange Elements are nearby.

So how does it work? Well, it’s a roof rack, and it works fine. If anything, I’d consider raising it a bit higher, and to be honest, I think I use it a lot more frequently when I need to tie down the back window when hauling things that stick out the back, which is good enough for me. In total the cost with the square tube, hardware, and paint, was probably around $30, which is a lot cheaper than a roof rack purchased.

giant-led-cube-02

This year my “big” project for Maker Faire Milwaukee was a Giant LED Cube. In this post I’ll talk about designing it, and in a follow up post I’ll talk about building it.

I should mention that the idea for this started maybe three years ago. I think it was during a meeting for Maker Faire at Milwaukee Makerspace and I tossed out the idea of building a giant light sculpture using light bulbs. Lance and Chris talked about it a bit and Tom started looking up parts on Alibaba. Nothing came of it that year, and I sort of forgot about it for a while. In fact, I really didn’t think about it again until after we completed the DecaLight last year. Once the two dimensional relay controlled light bulb thing was done I thought going three dimensional would be a good idea.

I modeled the cube in OpenSCAD, and then animated it just for fun. I figured out how many pieces of each PVC joint I would need, and while I originally thought a 20′ cube would be a good idea, after some initial tests (and the unavailability of 10′ PVC pipe) I ended up going with a 10′ cube so the 5′ PVC pipe I could get would work.

I picked up Jordan Bunker’s book PVC and Pipe Engineer: Put Together Cool, Easy, Maker-Friendly Stuff last year and then ended up learning about FORMUFIT which allows you to build furniture using PVC pipe. I had a plan!

giant-led-cube-01

Here’s the first sketch of the Giant LED Cube. By now I had decided that I would use LED light bulbs and standard household lamp sockets. The nice thing about using such common parts is that they are very cheap. I found these Black Bakelite Fixture Socket with Terminals and ordered some so I could test the fit. It was close enough that it would work, and I just needed to make a small adapter. Well, at least 27 small adapters.

giant-led-cube-04

I designed and 3D printed over 30 of these using clear ABS, which is remarkably close to being white, and since you wouldn’t really see them, I was fine with the close match. I cranked these out so I’d be ready when they were needed. Like many parts of this project, they are just press fit into place. The entire thing was designed to be easily assembled and disassembled for making transport and storage an simple affair.

giant-led-cube-03

I had the basic design of the cube figured out, so I decided to work on the controller. Since we’d have 27 LED light bulbs I decided to use an Arduino Mega, which had plenty of I/O pins, along with two 16 channel relay boards. LED light bulbs are pretty lower power (compared to incandescent bulbs, anyway) so even though they’re 110 volts AC, 27 bulbs all on at the same time probably pulled less than 6 amps.

The image above represents my first attempt at layout out the controller, which I eventually abandoned. The screw terminals ended up not being a good idea. I would be pretty busy running Maker Faire so I assumed that I could find helpers able to strip wire, put them into the screw terminals, and get it all right. After attempting this myself on a small scale I decided that it needed to be even simpler, and clear enough that almost anyone could do the setup. So I scrapped the screw terminals. Around this time I also decided that running all of the power cords inside the PVC was going to be tedious and difficult, so with the decision to just run the cords on the outside (at least for this installation) I decided to just use standard household plugs. This would allow nearly anyone to just match up some numbers and plug things in. Simple wins!

The design process for the Giant LED Cube wasn’t too difficult. Doing this like this (designing, specifying parts, building, etc.) is pretty much my day job. The wiring was definitely tedious, and required at least one unexpected hour-long troubleshooting session due to a bad connection. I had a lot of help with the wiring of the lights from Adrian, and a lot of help with initial assembly from Becky. Without their help things would have taken me a lot longer. (Thank You!)

I think I’ve spewed enough about this project for one post (which I wanted to get out last month!) so I’ll end it here and get working on Part II ASAP.

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