Category Archives: geek

Considering tech and the home

I came across an interesting exercise in Barbara Sher’s I Could Do Anythng If I Only Knew What It Was: to pick a scenario and try fully committing to it, even just for a little while.

Let’s say that this current lifestyle is the thing that I’m going to fully explore. I’ve started thinking of it as blending technology and non-technology interests, building a little on the idea of exploring that future where tech is more integrated into the home. I’m not the only one exploring it (yay!), but there aren’t that many people with the opportunities to do so yet, so maybe I can bring some useful ideas and insights to it.

So: laser cutting and sewing, Emacs and cooking, days with the abundance of time that science fiction writers used to predict we’d enjoy.

What would this life look like, carried to its fullest extent? What steps can I take to move towards that? How would this life evolve as technology advances and my skills improve?

One direction people go with lives like this is that of homesteading: building up more independence by growing and making more things. I like being close to the library, subway, and supermarket, so maybe that lifestyle isn’t quite for me yet.

Another direction is to stay where you are, but improve the way you do things.

  • I want to make more customized things, like the way I like wearing the tops I’ve sewn. Who knows, I might even get good enough to sew things for other people. As I get better at imagining and constructing things, I might also be able to apply those skills to laser-cutting, 3D printing, and other manufacturing technologies.
  • I want to get better at repurposing things, getting more value out of stuff before we recycle or trash them.
  • I want to gradually swap out more of our consumables with reusables. For example, I can make produce bags out of mesh. Then we won’t need to use plastic bags for fruits and vegetables.
  • I want to cook a wider variety of recipes, and I want to prepare each recipe better. I also want to get better at transforming leftovers.

I feel a little odd about a life that seems so focused on such a small area (of interests, of geography, etc.). I feel some internal resistance around that. But hey, Emacs is a pretty niche thing too. Besides, it might be interesting to take notes and see where this goes.

Related sketches:

2015-03-27b Resistance to different dreams -- index card #resistance 2015-04-16a Imagining a week of taking it easy -- index card #relaxing #life 2015-04-16b What does my Resistance sound like -- index card #resistance 2015-04-16d What if I extrapolated this rest to awesomenss -- index card #life 2015-04-16e How can I cross-pollinate interests

Emacs Hangout 2015-04-15 show notes

We chatted about packages, packaging, databases, and the upcoming Emacs conference.

Event page: https://plus.google.com/events/c3igul0rj6cfc1qbcar91lrcj0s

What’s this Emacs Hangout thing about? This is an informal way for Emacs geeks to get together and swap tips/notes/questions. You can find the previous Hangouts or sign up for the mailing list at http://sachachua.com/blog/tag/emacs-hangout/ .

Upcoming Emacs Hangouts:

Emacs Lisp Development Tips with John Wiegley
April 28, 2015 Tue 4:00 PM Toronto time (8 PM GMT)

Emacs Hangout
April 30, 2015, at 2 PM Toronto time (6 PM GMT, 8 PM CET):

Want to find out about upcoming hangouts? You can sign up for notifications at http://eepurl.com/bbi-Ir or follow the Emacs conferences and hangouts page.

Timestamps are approximate since I was a little distracted. =)

  • 0:25:14 8:26 PM whoops, forgot to keep track of stuff. Before this: conversation about Unity/C#/etc. in Emacs; Spacemacs
  • 0:26:33 Howard demonstrates literate database queries with a remote SQL server. SSH tunnel + –protocol=tcp
  • 0:28:55 Naming the results of queries and then using them in a different calculation
  • 0:30:39 Hmm, might be a good technique for exploring old databases
  • 0:31:13 sx.el – StackExchange client
  • 0:34:16 howdoi-emacs
  • 0:34:57 sx setup, sx-tab-all-questions
  • 0:35:59 hydra sample use cases: opening files and directories, changing the quotation of strings, mode switching
  • 0:37:30 clone indirect buffers
  • 0:39:35 Cask
  • 0:43:27 use-package
  • 0:44:57 paradox
  • 0:49:11 packages
  • 0:56:02 Emacs conference stuff
  • 1:05:11 weird Emacs things =)
  • 1:07:43 Next up: literate config (Dylan, Sean)
  • 1:13:19 wrapped up

Text chat and links:

me 8:08 PM By the way, we can use this text chat as a backchannel. After the chat, I’ll copy it and share it with the show notes so that other people can grab links.
Howard Abrams 8:14 PM Here is my investigation of my save hooks in case you can kick off some sort of script: http://howardism.org/Technical/Emacs/save-hooks.html
me 8:15 PM External to Emacs, but possibly interesting: https://github.com/infospace/guard-java
Dylan Thiedeke 8:16 PM You said there was a ruby-guard? I will have to look into that for authoring and editing cookbooks and recipes for use with Chef
me 8:17 PM https://github.com/guard/guard ?
Dylan Thiedeke 8:18 PM Awesome! Will definitely be looking at that thanks Sacha
Swaroop C H 8:20 PM csharp layer – https://github.com/syl20bnr/spacemacs/blob/064a598bff56f7cef1ac2ddf1c43684357dde56a/contrib/lang/csharp/README.md ?
M. Ian Graham 8:21 PM Nice link Swaroop, I’ll see if I can pull it in
me 8:25 PM http://emacswiki.org/emacs/GnuGlobal
Swaroop C H 8:26 PM https://github.com/syl20bnr/spacemacs/pull/1169
Sod Oscarfono 8:32 PM +1 for being a bassist!
M. Ian Graham 8:32 PM https://github.com/vermiculus/sx.el
Howard Abrams 8:32 PM Here is the blog post about the literate database work: http://howardism.org/Technical/Emacs/literate-database.html
me 8:34 PM https://github.com/arthurnn/howdoi-emacs
Zachary Kanfer 8:48 PM There’s an Emacs song: https://www.gnu.org/fun/jokes/welcome-to-gnu-emacs.html and http://www.emacswiki.org/emacs/LyricMode
Samer Masterson 8:53 PM gimmie a sec, getting headphones
me 8:56 PM Question from a viewer: Why would someone use both Cask and use-package at the same time https://raw.githubusercontent.com/rejeep/emacs/master/init.el ?
Sod Oscarfono 8:57 PM i’m an ex-event manager… i’d be keen on helping get one happening in oceania
me 8:57 PM Oooooh
Sod Oscarfono 8:57 PM nz or aus maybe
Samer Masterson 8:57 PM https://goo.gl/forms/tv0sDuApd8
Dylan Thiedeke 8:57 PM Sod I’m in AU. Not qualified enough to present but would help out if I could
Sod Oscarfono 8:59 PM thanks Dylan. perfect/ any ideas on a rough idea of numbers of emacs users globally? by region? hard to quantify i realise but are we talking hundreds, thousands, hundreds of thousands do you think? keen as Samer… i’m nowhere near as proficient with emacs, or programming as most here but i have many other skills.. event management, audio engineer, graphic design and close connection with large format commercial printer
Dylan Thiedeke 9:03 PM Sod in Australia I couldn’t even imagine a number. Maybe poll the #emacs IRC channel on friend and the emacs group on G+
me 9:03 PM Sod: Woohoo! Awesomeness.
Dylan Thiedeke 9:04 PM Sod I’m not a programmer either but use emacs for documentations and starting to use it for project management with org-mode etc
Sod Oscarfono 9:04 PM community is the magic word when talking to me
Samer Masterson 9:04 PM emacsconf.github.io/emacsconf2015
Sod Oscarfono 9:05 PM feel free to add me Dylan we can fire some ideas back and forth. maybe a poll of interest in a local conf or meetup
me 9:06 PM Sod, Dylan: Neato!
Howard Abrams 9:07 PM I’m sorry, but I have to leave as well. Thanks for the fun and I will listen to the rest later.

Laser cutting update: Marvel version

I cut the Marvel-licensed fabric that I picked up from Affordable Textiles on Queen Street (near Spadina) on the laser cutter. It worked out beautifully. I reused the SVG I tweaked after last week’s experiments. As it turns out, even with a 45″ one-way design, 1.5 yards is enough for a top, enough bias strips to bind the neckline and armholes, and two pairs of liner squares. There will be small scraps that I can use for other projects, too.

2015-04-14 21.52.43

This will be my 12th top, and I have the fabric for a 13th if I wanted to. I’m currently wearing the top that I laser-cut out of 100% Italian cotton. 100% cotton seems much more comfortably breathable than the polyester-cotton blend in the broadcloth that I practised with. Maybe I’ll do a few more tops as I come across colours and patterns that I like, and I’ll also gradually branch out to other patterns as well.

A checklist of things to try, fabric-wise:

  • Cotton
    • Fabric ordered online – maybe this cute Dr. Seuss fabric or something else from Jo-Ann (or maybe this one), to remind me to have fun
    • Something from Etsy
    • Fabric using someone else’s design, maybe off Spoonflower
    • Fabric I design
  • Stretch knit
  • Silk or other slippery fabrics

Mwahahaha. =)

2015-04-14d Laser-cutting fabric is awesome -- index card #laser #hacklab

2015-04-14d Laser-cutting fabric is awesome – index card #laser #hacklab

Experimenting with spending more time at Hacklab

This week I experimented with making Hacklab my default location. I biked there on Monday and Tuesday because the weather was good, and I took the subway on Friday because I wasn’t sure about the forecast for rain.

On Monday, I laser-cut pieces for the simple tops that I’ve been sewing. I’ve been skipping the pleat, since it doesn’t make any difference to the fit of the garment and skipping it makes the top easier and faster to sew. The pattern fits the laser cutter if I cut it on a fold, and I can cut registration marks on a sheet of paper to make aligning that fold easier. I cut the pieces for one top out of the peach broadcloth that I’d salvaged from my box cushion prototype. (Waste not, want not!) I cut the pieces for another top from a black gingham check that I wanted to experiment with, since it’s supposed to be one of this season’s trendy patterns. I was delighted to find that the laser-cut pieces actually matched up – not just in terms of the notches (which I can take credit for), but even in terms of the pattern. (Probably more coincidence than skill.)

I didn’t pay attention to the direction of the gingham check because I assumed the stripes were the same visual weight. It turns out one direction is a bit heavier than the other, so now my shirt has horizontal stripes when it looks like most of the commercial gingham shirts I’ve seen had dominant stripes (if any) running vertically… Ah well! I cut bias strips and wrappers for another experiment out of my excess yardage, so I don’t think I have quite enough left to make a new shirt. I’ll finish and wear what I have. If I decide it’s worth doing another gingham thing, I might be able to get half a yard and do another one.

On Tuesday, I came early so that I could get some bread dough rising while I went for a massage. (Knead and be kneaded?) That worked out well, and we had some lovely crusty bread for the open house dinner. Eric and I also checked out this community garden in the neighbourhood. Our chances of getting a plot are probably pretty low (long waiting lists), but apparently they have a small herb area that could use more volunteers, so we might give that a try. Alternatively, Alex says it’s okay for us to set out planters in the back, and he even has an automated watering system. It would be great to grow lots of basil and other herbs for cooking.

Today I went to Hacklab to talk to a friend. Since I was in the area anyway, I also took the opportunity to pick up some bamboo fabric from Designer Fabrics so that I can look into making a pair of yoga pants.

I wanted to laser-cut the bias strips for the gingham check. I thought about using the 10″ square continuous method, but I settled for making long bias strips instead so that I could fit an extra square in there for another project I’m working on. While I was sorting that out, Alex came in with a MIDI keyboard, a laptop, and a projector. He proceeded to set it up to project the keyboard training program onto the keyboard itself, which was really nifty. We had fun playing around with different pieces.

Mmm. I like this. Going to Hacklab nudges me a little more towards making stuff and talking to people, I think. Let me see what next week is like. On the flipside, it means less time at home and less time preparing meals, but if I leave Hacklab earlier and I plan what to cook, I can probably still have that in place by the time everyone’s ready for dinner.

On another note, Designer Fabrics didn’t have any polyurethane laminate (PUL – waterproof, breathable, washable in hot water; often used for diapers, but good for general waterproofing and even making food-safe lunch bags and other containers). Fabricland has some, but it’s a bit pricy at $33/m. It seems people tend to order that online, so I might give online shopping a try.

2015-04-08 Emacs Lisp Development Tips with John Wiegley

You can find John Wiegley on Twitter (@jwiegley) or at http://newartisans.com/.

0:00:00 Paredit mode. Start with it from day 1! Matching pairs of parentheses, won’t let you delete one without the other. Inserts appropriate newlines, too
0:03:56 Emacs as a Lisp environment. (Also, Helm is what’s responsible for the display.) Evaluating a function makes it available in the global scope, which has all these functions and commands you can do. This makes it easy to iteratively develop your functions, because you can just execute things directly.
0:05:08 Without (interactive), you can’t call functions with M-x. You can use M-: or put the call in your scratch buffer.
0:06:00 command-log-mode
0:06:47 pp-eval-last-sexp. Check out http://github.com/jwiegley/dot-emacs for other config things
0:07:14 debugging. e to evaluate within the current context. Also, stepping, quit.
0:08:09 Edebug with C-u C-M-x. Interactive debugging. SPC moves you forward, one Lisp form at a time. It shows you results in the minibuffer. You can descend into Lisp forms or go into functions. ? shows keybindings. Check out the Emacs Lisp chapter on EDebug, highly recommendeg.
0:09:25 You can also use the (debug) form to go to the debugger.
0:10:26 eldoc: Seeing arguments in the minibuffer as you type, because no one remembers all the arguments anyway. eldoc-mode, or add (turn-on-eldoc-mode) to your config.
0:11:30 What functions should you call in the first place? What concepts? Emacs predates many standard terms, so that’s why things are a little confusing. Ex: “frames” and “windows” are not what you might think they are. OS window = frame. Area within Emacs = window. Opposite of HTML. Use the Emacs tutorial C-h t.
0:13:04 Read the Emacs Lisp intro, which you can get to with C-h i (which lists the manuals that are available). Read the Emacs Lisp manual too.
0:14:03 Other weird terms: point, mark, marker. (point) vs (point-marker).
0:15:35 C-h f (describe-function) shows the help for the function. Nearly all functions you’ll probably call are documented well. Lots of options. Check out C-h f for interactive, for example.
0:17:17 C-h v (describe-variable).
0:17:46 More in-depth documentation: C-h i, go to the Emacs Lisp manual, then use i to view the index.
0:18:22 info-lookmore shows you the Info documentation for the symbol under point. Works for other Lisps too (ex: Common Lisp)
0:19:46 Sanity-checking paired parentheses with M-x check-parens. Handy for adding to your after-save-hook in Emacs Lisp mode.
0:20:40 Paredit editing capabilities. Ex: C-k kills the current sexp. paredit-raise-sexp replaces the parent sexp with the following sexp. slurping and barfing. Barfing – spitting out an element from the list form. C-{ or C-} (with suggested keybindings). C-( and C-) are slurping, which pulls forms in. Works for strings, too.
0:22:38 Maximum barfage and slurpage. Useful for slurping everything in, for example. paredit-slurp-all-the-way-forward.
0:24:13 redshank (companion to paredit) for refactoring. Ex: redshank-condify-form converts an if to a cond for when you realize you’ve got more than two conditions.
0:25:05 M-1 M-( surround the next one thing with parens
0:25:25 redshank: wrap a let, change if to a when, etc.
0:25:52 C-h k (describe-key) shows what a keyboard shortcut or menu item will do.
0:27:26 Took a while to get used to paredit, but you eventually get into the zen of paredit.
0:27:54 Linter – M-x elint-current-buffer. Loads every module that your code depends on (so the first time is slow), and then shows you style notes.
0:28:50 C-q for manually inserting parentheses
0:29:10 Helm, which shows you all the other stuff that matches your query. Lets you select by regex, multiple patterns, etc. Much nicer and more interactive.
0:30:29 Profiler M-x elp-instrument-function, then call the function, then elp-results will show you the time it took to execute. Results aggregate, and are reset when you call elp-results.
0:32:30 Measuring memory consumption. Also, internal representation of lists. reverse vs. nreverse. Like nconc, nreverse, setcar, setcdr. This can greatly speed up your code, if you can avoid using the garbage collector. EmacsWiki – memory-use-counts, but not particularly helpful? Another package that extends the Emacs Lisp profiler? Avoid premature optimization.
0:38:55 elint and flycheck? flycheck’s designed for external processes, so that might be a challenge. Possibility: use async to spawn another Emacs? Doesn’t seem to be available yet.
0:40:40 ert
0:48:11 testcover, coveralls.io, undercover.el
0:48:13 Read Emacs Lisp manual, etc.
0:48:20 Creating a mode. You don’t have to make it from scartch – start by copying someone else, and then strip away everything you don’t want.
0:49:58 checkdoc – checks the style of your documentation strings.
0:51:30 defining a minor mode
0:56:08 when to define a major mode – structure of your buffer

Laser cutting registration experiments and cutting long pieces of fabric

(aka Things Other People Probably Already Knew About the Hacklab Laser Cutter But That I Wanted to Figure Out =) )

For sewing purposes, I want to eventually be able to accurately cut pieces that are larger than the laser bed (22×18″). The approach that other people had recommended for large cuts is to laser-cut a piece of paper, then position material on top of it. This works really well for acrylic and other clear materials, but it’s a bit trickier with fabric.

I was curious about the following questions:

  1. Do the cutting bounds coincide with the mat if the grid has been removed? If so, then placing material would be much easier.
  2. Can you use registration markers to make the process of shifting opaque material easier?
  3. Can you build pauses into laser programs to make it easier to reposition material or adjust power?
  4. Do you need to keep stroke width in mind when setting the X and Y locations for paths in Inkscape? That is, when you set the X and Y, does it use the path (which is what’s used for cutting), or does it use the stroke width?
  5. Is the lowest leftmost position stable? That is, if you rehome the laser and then use the joystick to move it to the minimum X and Y the hardware will let it reach, does that position stay the same even if you repeat the process?

To explore these questions, I created an SVG that had

  • L-shapes to define the corners
  • a couple of crosshairs for shifting, and an additional reference line that could be checked against the X=0 line
  • two half-circles that would become one circle after shifting

Since Inkscape’s Gcode tools export the path names, I used Path – Combine to group related paths and the Object Properties dialog to rename them. This allowed me to edit the resulting Gcode, move the path for the second half-circle to the end of the file, and add an M0 pause before it. I taped paper down to cover the four corners. After processing the file with the sed scripts used to tweak things for our laser, I ran it.

Here are the results:

1. The cutting area does not coincide with the rulers or the mat.

I homed the laser and then touched off at the minimum X and Y positions that the hardware would let me reach. The lines I cut for the upper corners are slightly skewed away from the built-in ruler, which means that it cannot be used for alignment.

2. Registration marks allow for reasonable precision in large cuts.

2015-04-06 12.40.222015-04-06 12.36.01

The circle above is formed from half-circles, cut in two passes separated by a reposition. I started with two sheets of paper taped to the lower left corner: one to move, and one to act as a reference. After I made the first cut, I repositioned the top layer of paper so that the crosshair on the right was on top of the crosshair on the left and the reference line I cut was aligned with the lower left corner. Folding the quarters of the crosshair back helped me verify its position. I taped the top layer of the paper down and proceeded with the second cut. This simple registration process produced a cut that’s not completely accurate, but which is manageable for the kind of work that I want to do. It could probably be refined with additional crosshairs, boxes, or other registration shapes.

(Update: Boxes work wonderfully.)

3. You can use the M65 P0 and M0 operations to add a pause to your G-code program, but the program will be reset if you raise the lid of the laser.

The M0 operation pauses the program, and you can continue it by clicking on the pause button in the controller. However, when you raise the lid of the laser to reposition material, the controller loses the connection to the laser. After you reestablish the connection, the controller is no longer in pause mode, and you need to start the program from the beginning.

Because my G-code was relatively simple, I chose to re-run the program with zero power. When I reached the pause, I set the power to level 1 and continued with the program. This may be a good way to handle larger cuts if you want to keep the design in a single G-code file. Here’s a snippet showing the pause code.

M63 P0

(End cutting path id: upperleft)

M65 P0
M0

(Start cutting path id: secondhalfcircle)
(Change tool to Default tool)

M63 P0

M65 P0 turns off the laser immediately (instead of being synchronized with motion), and M0 pauses the program until it’s continued from the controller.

If you don’t want to pause and rerun, you can always split your cuts into separate G-code files. Dividing your SVG into layers makes it easy to select all the paths on a given layer before running the G-code export tool.

4. Inkscape takes stroke width into account when you move paths using X and Y, so be consistent about your positions.

If your stroke width is 1 px, then a line drawn on top of a 1″ grid from (0,0) to (0,2) will start at (-0.006″, -0.006″) and have a height of 2.006 inches. This can still be cut. If you move it to (0,0), the actual line itself will be offset by a tiny bit, although I’m not sure how much difference it would make when cutting. Anyway, when creating registration marks, make sure you have a consistent offset between your registration marks and the path to cut, and that you use a consistent stroke width (even if the laser cutter ignores that width). Make sure you turn off the default preference that scales stroke widths whenever you resize something (Edit – Preference – Behavior – Transforms – Scale stroke width, or use the fourth icon from the right of the top toolbar).

5. The lowest leftmost position appears to be stable.

If you home the laser, then use the joystick to move to the minimum X and Y position you can reach in the lower left, and you use the GUI controller to touch off at that point so that all coordinates are relative to that position, then your cuts will be in the same place each time. This appears to be true even after you rehome the laser and re-touch-off, and even after you turn off the laser and restart Linux EMC2. This means we could probably mark off the outside limits of the cutting area on the mat using something that’s laser-safe, and then people could use those as reference lines. On the temporary side, there’s taping down paper and using that as a guideline, which people are used to already.

Whee! So with the results above, I should now be able to make decently-precise long cuts in fabric…

2015-04-06 15.10.27 2015-04-06 15.09.58

MWAHAHA. Behold the power of the laser cutter. The pattern pieces are about 23″. This is the picture of a cut after the piece has been shifted so that the registration squares on the right of the fabric is over the registration squares on the left on my reference piece of paper. There’s a barely-perceptible jog in the line, and since that’s in the seam allowance instead of in a design, it’s totally okay.

All right! See files at https://github.com/sachac/laser if you want to explore.

Accurately tracing and cutting patterns makes the rest of sewing so much easier because you can go by the seam allowances. Since long cuts on fabric turn out to be Not That Scary, I can use this for cutting the pieces to sew together. For fabric that is harder to handle or laser-cut, I can use the laser to cut pieces that I can then pin to the real fabric for hand-cutting (since fabric patterns can be easier to handle than paper). Mwahaha!