I finally, totally get 3D printing

I’ve been flopping back and forth about what equipment to get/build next, assuming I saved up a few thousand dollars: a CNC router? …a laser cutter? …a 3D printer?

This weekend I totally got what I would do with a 3D printer: print mechanical parts of machines.

In search of stepper motors in old, broken devices, I tore apart an ancient HP Deskjet inkjet printer – something like an 810C – I forget what model exactly. At any rate, disassembling that printer was an education in the mechanical design of moving parts.  It used normal DC motors (no steppers) to drive the printer head and paper, then used stripes on film sensed by photo-interrupters to determine where exactly the print head was and exactly how far the paper had advanced.  Very impressive!

In going over the design of this amazing machine, and in thinking about what parts I could salvage from it, it suddenly struck me: I could reuse many expensive parts if I could print my own mounting and connecting pieces – the application-specific parts that hold, for example, a linear rail or connect a print head to the bearings that ride on the rail, or even a piece that holds a tension spring and the sprocket that it tensions.

So many things in this printer are accomplished by little custom pieces of plastic – the sort of pieces you could print in a 3D printer.

This short video on open-top printing has some nice closeups of the sorts of mechanisms and parts that I’m talking about.

Adding A Finish to the Glockenspiel Case

Previously I finished the labels for the glockenspiel. In this post I literally Finish the case.

Last weekend and this weekend are nicely warm enough, so I’ve put a few coats of Minwax gloss polyurethane  finish on the Robotic Glockenspiel case.  In a few days the finish will be dry, and I can do the final fine-sanding (to remove dust captured in the Finish) and assemble the thing.

Finishing the Glockenspiel case
Finishing the Glockenspiel case

P.S., don’t copy my style of finishing – I’ve not learned how to do it well, and here I’ve not done most of what you want to do to make it come out right. I haven’t put down a drop cloth or newspapers to keep the surroundings from being Finished; I haven’t used pinpoint-tip stands to keep the work from sticking to the support table; I haven’t sanded between coats to remove dust/pollen; I’ve sprayed when it was breezier than it should be.

That said, I expect it will turn out well enough for this first-prototype, and functional enough to keep dirt from getting into the wood. (How many times have I said “the end is in sight”?) The end is in sight!

Next I complete the project at last!

Final labels for the glockenspiel buttons

Since trying out woodburned labels, I made another attempt at scrollsawing the button labels for the Robotic Glockenspiel, and am happy enough with the results that I’ve glued the labels to the glockenspiel box. I’m so happy to have finally made up my mind – whew!

So this blog is a sort of “how to scrollsaw” in a nutshell.

First, print out your pattern on paper. Make sure to print outlines rather than solid shapes, because the edges of solid shapes are hard to follow with the scrollsaw’s blade.

Next, use a glue stick and a roller to stick the printed pattern to the wood you want to cut. Some people like to use temporary adhesive, but I’m partial to glue stick.  For any closed spaces, drill a hole the size of your scrollsaw blade.

Pattern glued to the wood. Note the drilled hole in the O
Pattern glued to the wood. Note the drilled hole in the O

Next, cut the pattern out using your scrollsaw. For any closed spaces, unhook the blade, slide it through the hole you drilled earlier, reattach the blade, then cut the space. By the way, one of the things I love about my new saw (RBI Hawk) is that it’s made to do this sort of “pierced work” very quickly.

Cutting the wood. The circle interior is cut
Cutting the wood. The circle interior is cut

Once all the pieces are cut, admire your handiwork for a moment :-)

All the button labels cut out and lying on some scrap wood
All the button labels cut out and lying on some scrap wood

Next, remove the pattern paper from the cut pieces. If you used temporary adhesive you can peel the paper off. I prefer to sand off the paper because that sanding also removes any glue residue which would interfere with the Finish of the wood.

Sanding one of the cut labels
Sanding one of the cut labels

Once I sanded all the button labels I glued them to the glockenspiel box with white glue (carpenter’s glue) and clamped them down until dry.  Observe the lovely result!

Glockenspiel box with scrollsawed button labels glued on
Glockenspiel box with scrollsawed button labels glued on

Next I can (once the weather warms up) spray a clear finish on the glockenspiel box and reassemble all the hardware.

Wood-burned Glockenspiel labels

In my previous post, I scrollsawed labels for the glockenspiel buttons. This morning I tried out pyrography – wood-burning – to label the Robotic Glockenspiel buttons, using  a piece of scrap wood of the same material as the Glockenspiel box.

First I transferred the printed image to the wood using carbon paper and a stylus. I tried using an iron to transfer the pattern directly from the laser-printed paper, but found that works best (that is, at all) on inkjet prints rather than laser printing.

Pattern, carbon paper, and stylus
Pattern, carbon paper, and stylus

Next, I used a wood-burning iron to define the edges, then fill in the spaces. The result is pretty um…”rustic”, but not bad for having done almost no wood-burning before.  I’m still deciding whether I’ll go with this (pretty sloppy) or try thinner wood and my scrollsaw.

Woodburned glockenspiel labels
Woodburned glockenspiel labels

One advantage I just realized about raised, scrollsawn labels: the icons are simple enough that you can distinguish them with your fingers alone – great for people with visual impairments or for controlling it in the dark.

In my next post I return to scrollsawing the labels.

Scrollsawed button labels for the Glockenspiel

Since putting a lid on the glockenspiel case, I’ve been wrestling with exactly how to label the robotic glockenspiel buttons: If I had a laser engraver I probably would have engraved (woodburned) the labels on; sticking paper labels on could look pretty sloppy; decals sounded like a production of their own, with the risk of gumming up my printer; painting the labels would require a steady hand; woodburning by hand is another option; so is gluing on scroll-sawn raised labels.

So today I tried out my new (used) RBI Hawk 220 VS scrollsaw, that I’d cleaned up a few weeks ago.

Hawk 220 VS Scrollsaw
Hawk 220 VS Scrollsaw

Looking at the result,  I don’t think I’ll go with scrollsawn button labels: the labels look good, but I think they need to be more precise and on thinner wood. I’m also concerned that they could pop off the glockenspiel box pretty easily as I move the box about.

Scrollsawn button labels, laid on the box's wood
Scrollsawn button labels, laid on the box’s wood

By the way, the RBI Hawk is a sweeeet scrollsaw, far better than my old Sakura (knockoff of a Strong-brand saw). Even as old and worn as it is, it makes a really good cut.

The more I look at the scrollsawn labels, the better they look, but I think traced and woodburned labels will work better for the glockenspiel.

So next I’ll try transferring the labels’ pattern onto the wood  and woodburning it.

How to soften LED light with a ping pong ball

Some time ago I read that you can use a ping pong ball to soften the harsh light of an LED, so I thought I’d try it out.

Step 0: pick out a white ping pong ball.  I used a standard 40mm ball; I could have used a 35mm Foosball instead.

Step 1: make a hole in the ping pong ball to hold your LED. For a 5mm LED, an ice pick heated on a stove top is an handy tool for making that hole. I have’t tried a drill press, but that seems another possibility.

Ping Pong ball with hole for LED
Ping Pong ball with hole for LED

Step 2: set up a circuit to blink an LED, perhaps using an Arduino Pro Mini.

LED ready for the ping pong ball diffuser
LED ready for the ping pong ball diffuser

Step 3: press the ping pong ball onto the LED.  For a more permanent mechanical connection, you could glue the LED into the ping pong ball using a hot glue gun.

Step 4: Enjoy the magical, diffuse light of the LED in the ping pong ball.  You may need to turn out the lights to see it well. Have a look at my low-key YouTube video of the result.

So a ping pong ball really is a quick and easy light diffuser for your LEDs – disco time! …or you can paint pupils on them to create blinking night-creature eyes as in this video.

The glorious ping pong ball LED light diffuser
The glorious ping pong ball LED light diffuser

Arduino Pro Mini, and how to solder male headers

I recently decided to try out the Sparkfun Arduino Pro Mini 5V board.  It has almost all the I/O that an Arduino Uno has, in a much smaller board. It comes without connectors, so you can solder in whatever style connector you need. For my uses, I needed to solder on male headers that allow it to plug into a breadboard.

So I tried out a new way of soldering male header pins onto a board. First I snapped off two 12-long headers from a strip of break-away male headers. Then I plugged those headers into a breadboard and laid the Arduino Pro Mini board over them.  To keep the flux and solder spatter from getting into the breadboard holes, I put a piece of paper over the unused parts of the breadboard.

Male Pin soldering, step 1
Male Pin soldering, step 1
The paper keeps solder and flux spatter out of the unused breadboard holes
The paper keeps solder and flux spatter out of the unused breadboard holes

With the pins plugged into the breadboard, the Arduino Pro Mini dropped onto those headers, and the paper protecting the breadboard, I soldered the pins. I then unplugged the board from the breadboard, and  used my regular QuadHands to hold the programming pins to the board, because those pins point “up” instead of down.

The result was fine. I did have a little trouble with the solder, but I just need a little more practice, and I need to clean the soldering iron’s tip better.

The soldered Arduino Pro Mini, ready for use.
The soldered Arduino Pro Mini, ready for use.

Next I tested each of the pins. Notice in the picture that I’m using the Sparkfun 5V FTDI breakout to connect the Arduino to the laptop. It works like a charm!

Testing my soldered Arduino Pro Mini
Testing my soldered Arduino Pro Mini

Now all I need to do is decide what to build with this tiny, easily-battery-powered Arduino – whee!

CareSwears – an automatic Swear Jar

For some reason I like this crazy idea: an automatic swear jar that uses web voice-recognition to identify curses, and uses a BitCoin (ugh) API to pay $0.25 to the BitCoin-accepting (?) charity of your choice.

You have to admit, it’s cute. Disregarding the privacy and currency issues, it’s still different. Is it Gamifying behavior change? …or is it re-imagining an old and popular interaction?

http://challengepost.com/software/careswears describes the Hackathon project.

Putting hinges, lid on the Glockenspiel

Since fixing the sound of the chimes,  I’ve been finishing the software for the glockenspiel. Now all the buttons work: on/off, play/pause, skip back, skip forward, and shuffle. Woohoo!

Today I made the lid, attached the molding on the edges of the lid, attached the piano hinge and attached the side hinges. It’s not fine furniture, but I’m learning a lot about how to make The Real Thing. For example, don’t sand the wood with the sandpaper you used to remove rust from your new scrollsaw (ouch!).

All the hardware (except the front latch and the feet, which should install easity) is now installed.  So now I’ve taken all the hardware off so I can easily do the labels and spray the finish.

Next I plan to label the buttons – I plan to try woodburning – the end is in sight!

The lid is built
The lid is built