Saturday, June 6, 2020

Oh, that's better

This is my third completed tesseract.  The second wasn't particularly successful, and not really worth talking about right now.



There are several changes from the previous one:
It's larger, to take the bulk of a rechargeable battery.
It's rechargeable.
I used a clear filament, so the whole thing glows with the LEDs, which is nice.
I added an ATTiny microcontroler to run RGB LEDs through the spectrum.


Man, am I happy with it.

Some process pics:

My first etched PCB!

Yes, it's small. Savvy observers will note that there are only three resistors for all eight LEDs; one each for red, green, and blue.  This isn't ideal, and the next will have each LED with its own resistor.


RGB LEDs wired in



The wires run up the spokes to the charging port and switch. They're fine enough that they more or less disappear inside the box.


I was constantly testing the LEDs to make sure wires hadn't wiggled themselves loose.



Thursday, April 16, 2020

Mass(k) production

I'm part of  a team organized by my employer to make a *lot* of masks for donation to area hospitals.  We're working in batches of 50.  I've streamlined the process with mass production in mind, and I'm documenting my shortcuts here.  Things to keep in mind about mass production: Tool changes are expensive, they cost time.  Figuring out what the next step is counts as a tool change.  Try to break your process down into the smallest possible steps, and do them for your whole batch before moving on to the next step.

With that in mind,

Step 1: cutting and material prep:

Wash and dry your fabrics on the hottest setting possible.  We want them as clean as possible, and to shrink as much as they're going to.  Iron all fabric before cutting.

You need:
 
  • 8" x 8" squares of your outer fabric, lining, and whatever inner fabric/filter/interfacing you're using. I'm using cotton quilting fabric, unbleached muslin, and Pellon non-woven sew-in interfacing.
    •  Tip: If you stack your fabrics before you cut, you'll spend less time adjusting and arranging things later.  Remember to put the face of the outer fabric against your lining, not the interlining.
  • Two 1 1/2" x 36" fabric strips, cut on grain. I'm using muslin here, too.
  • One nose stiffener, 4" finished, after the ends have been bent back.  I'm using a piece of 16(?) gauge aluminum wire I had lying around.

With your fabrics stacked, sew across the top with a 3/4" seam allowance, and then the bottom with 1/4".  (if mass-producing, do all of the tops, and then all of the bottoms.


Turn and press.  You'll get a neater edge if you press your seam allowances open first, and then turn them and press again. I'm not sure it's worth the extra time, for a little extra accuracy, though.
using a dowel, because I don't have a sleeve board


Next we're going to sew the channel for the stiffener.  I've given myself some guidelines on the bed of my sewing machine using blue washi tape.  They are 1 5/8" in front of the needle, 1 5/8 " to the left of the needle, and 1/2" behind the needle.

Make sure you have the side of the mask with the 3/4" seam allowance.


Match the left side of the mask to the left guideline, and stitch down until the top of the mask reaches the back guideline.
 
 With the needle down, lift the presser foot, and pivot.  Continue sewing a half inch from the edge, until the right edge passes the front guideline, and stop.  If you're only sewing one mask, you can put the nose wire in immediately, but for mass production purposes, I'd do this for all of the masks, then put all the wires in, then finish them all.

Insert the wire, making sure you're between the interfacing and its own seam allowance.  I found these long-nosed pliers handy.


Finish by sewing from the top edge down to where you stopped before, pivot, and stitch over the last few stitches to secure the seam.



Not quite clear?  Here's a video.

Next, we sew the pleats, and for that we're looking at the second set of guidelines: the pink tape 1" in front of the needle, and 1 1/4" behind.



Start sewing from the bottom edge of the mask and when that edge hits the guideline behind the needle, stop with the needle down.  Use a tool (I used a seam ripper, pretty much anything skinny will do) to lift the mask at the front guideline,

pinch it into a pleat,

and bring that fold under the presser foot and up against the needle.





Stitch 1/2 inch, and stop with the needle down.  For my machine, with its current settings, that's five stitches exactly.

 Lift the next pleat, pinch, position it under the presser foot and against the needle, stitch another half inch.  Repeat for the third pleat, and stitch to the end.



Once again, you deserve a video:



I've found it easier to move to the ironing board at this point rather than try to reproduce the pleats on the other side.  This takes some finesse, and improves with practice, but it's worth it.  I've found it easiest to take it as a gradual process.  First, make sure the three pleats form three waves on the other end, not just two. 


Pull the top and bottom edges so they're more or less parallel, and ease the pleats into position.



  Once you've got them more or less parallel, press,



and then stitch to secure them.

And again, especially because this is something my hands know more about than my brain does, video:



The ties are cut on the straight grain (not the bias!) because you don't need the stretch when binding straight edges, and you don't *want* the stretch for ties.

Make a little clip 2" on either side of the center of the tie. I did this folded, and in a large stack.


Actually sewing the ties is a bit too fiddly for me to take my own photos as I go, so I'm going to rely on the video, plus written instructions:



Take the end of the strip, fold down 1/4", and then fold the long edges to the center, and fold the whole thing in half.  Sew back and forth across the end a few times with the open side facing you, and the tie to the right of the needle. End with the needle down at the front corner, and pivot the tie to sew down the length.  Fold the edges in as you go, running a finger down the opening to encourage everything to stay straight and tucked and even.

When you get to the first notch, fold past it, but keep your finger on (or near) it, stopping sewing when you're just in front of the presser foot.

Fold in the edges for the next length of tie, and tuck the mask in between the layers.  Sew across the mask, and then continue down the second half, remembering to turn the last edge in.  Sew across the end, several times.

Repeat for the other side.

Trim all threads.



50 masks, approximately 16 hours, total

Thursday, March 26, 2020

Tesseract 1

To say that I was inspired  by Sean Hodgins' tesseract would be a massive understatement. I've spent the last three-ish weeks working on different ways of making one, for someone without easy access to tritium.

My first go is LEDs, using frosted acrylic rod to conduct the light along the length of the connectors.



One of the sides isn't glued in place, it pops out so I can access the switch on the inside.

Terrible photo! So sorry!

Similarly, one of the sides of the inner cube pops out, so I can replace the battery.  The battery is a 3V coin cell that's smaller than the standard 2032, and I'm not sure what I'm going to replace it with when it dies.  The 2032 won't fit in the box.  

I ran into a few issues.
I couldn't get mirrors as thin as his prints were designed for, and then the guys who cut my mirrors weren't very precise, so my mirrors didn't fit the prints I made from Sean's design.  So I dinked around on TinkerCad until I could make my own cubes.  I didn't plan for a switch on the outside (I didn't want visible wires running out from the center, but I think I know how to at least make it look intentional).  The acrylic rods didn't transmit light as well as I hoped.  Next time, I'll put something reflective on the far end, see if that helps.  I didn't really plan for a way to open it.  At the moment, the "door" side is held in place by just  a pressure fit, and is harder to get out than I expected.  Lastly, I was in a hurry to get it done, so I didn't give the super glue  enough time to cure, so the fumes frosted the acrylic slightly.

Overall, not bad for a first run, and I have a list of tweaks to make the next one better.

Friday, March 20, 2020

Electronics?!? What?

So, a few years ago, I spent a few years working part-time as a technician in an electronics shop.  I built cables, inspected circuit boards and replaced bad components, that sort of thing.  I gained a fair amount of technical skill, but while I knew what to do, I had no idea what I was *doing,* and that bothered me.

Years later, I'm finally doing something about it.

I worked through Make: Electronics and the Sparkfun Inventor's Kit (both editions; there was enough of a delay between when I decided to do this, and when I finally did it that the new edition was out, and an upgrade kit was available.  I do recommend the earlier edition of the SIK book if you're into that sort of thing, there are more different kinds of sensors covered.

And then I made some stuff.

I made a binary counter, that could theoretically be worn as a pendant, especially if you found a better means of power management!


I made digital dice!



And of course I did the whole range of usual intro to electronic projects, which weren't worth documenting.  It's fun!  And I have a much better foundation to build on.

What next?  Things get really fun.

Thursday, March 19, 2020

Not dead yet

I'm sure I'm not the only one who will be rebooting neglected blogs, in this time of social distancing.
I have plenty of projects to post updates on, and a massive backlog of photos, but I'm going to indulge my short attention span and focus on my current obsessions.  I am definitely still sewing; textile-related pursuits will not ever stop.  But right now, I'm focusing on electronics.  So this blog is going to be taking a bit of a turn, while I indulge my inner toymaker.









Stay tuned.

Oh, that's better

This is my third completed tesseract.  The second wasn't particularly successful, and not really worth talking about right now. There ar...