laptop sleeve… am i a hipster now

i acquired a new laptop (gently used by relatives)
consumerism ftw

i’m trying not to destroy this one

i impromptu decided I should make a laptop bag, having spotted a bag of cloth i picked up off reuse last semester, and deciding i need a laptop bag right now because two days is too long to wait

[x] img src

that made it seem so easy, like something i could finish in 15 minutes

i went to MITERS and turns out we don’t have fabric glue. so i decided this would be an excellent opportunity to learn to use the really cool sewing machine we have! i also picked up an old shirt and some strips of leather lying around MITERS (on top of the lathe — turns out we have a good selection of odds and ends of material)

This sewing machine is so amazing. It’s actually very clearly laid out, with instructions screenprinted right on the machine, and alkdjbnwet just amazing. It has this bobbin winder on top which works like a charm and maybe I will go back and take a picture of it. Actually no here’s a video: which shows how it will mechanically “automagically” stop winding when the bobbin is full.

The manual is very clear too.

anyway, in retrospect I cut the triangle very off-center. it looked roughly even at the time. whatever.

i also used the strips of leather for padding on the sides. I’m most worried about putting it in my bookbag and the corners/hinges getting damaged when I forget and set my bookbag none too gently. I don’t know if this is an actual cause of damage but for my own ease of mind…

i wish i’d found two shirts because i ended up only padding one side because I was getting tired of my emergency project. also lol it turned out so derpy but i am owning up to derpy projects because i feel like it would have encourage me as a beginning project doer ^__^

i made the strap with some velcro i sewed on.

one thing i would change going back is cutting it a little closer to form — it tends to slip so that the leather strips aren’t protecting the ends but rather the edges of the laptop.

project took 2.5 hours in total

Plotting a maker businesses meetup in Boston

A friend of mine suggested I find people to mentor me as I startup.

I naturally decided I should go Organize A Thing. To get a rough gauge of how many maker businesses / hardware startups there are in cambridge/boston, I skimmed through kickstarter by city (both cambridge and boston).
(sadly, you can’t sort by both “boston” and “technology”

The spreadsheet is here:

There will be edit privileges for the next few weeks or so for that link unless something terrible starts happening. Feel free to contribute notes.

The conclusion was that somewhere upwards of 30 companies, I think within the last 5 years, have been successfully fundedο»Ώ: (see google docs for links to the kickstarter pages) (accounting for there are probably companies I missed on my skim, and for instance Twine, founded by MIT Media Lab grads, would probably be willing to be part of the network even if they are not in Boston right now).

Additionally, I was linked to this site that already does data around kickstarter when I asked whether there was a graph of OneTesla’s funding:

The Companies:

  1. Fuel: The world’s smallest cell phone charger
  2. drive with dash
  3. monkeyoh
  4. 3doodler
  5. Carbon Fiber Jewelry Rings
  6. The Orbit Turntable
  7. Loud Bicycle: Car horn for your bike
  8. Mini Pouch for your iPad Mini, Nexus, Kindle and more
  9. Pocket Monkey: The Wallet Utility Tool
  10. iStrike Shuttle- iOS controlled drone
  11. Convertable Axis Bracket CAB / The Ultimate Cheese-Plate UCP
  12. The Pen Project
  13. The Kick – a pocket sized lighting studio for photo & video
  14. Knut: Stay Connected
  15. Corter Leather Bottle Hook
  16. Cam Crate: DSLR Life Proof Camera Case
  17. diFeltro Fold, Italian handcrafted bag for iPad
  18. The Retina Project
  19. The Clip by LittleBonsai
  20. FXdoctor 8-Bit Fuzz Pedal’s US Tour
  21. CEE: The USB analog electronics multi-tool
  22. WALdok :: Wall Plug-In Speaker/Charger for iPhone/iPods
  23. Modkit – Electronics (Arduino) for Everyone
  24. Lockpicks by Open Locksport
  25. Inevitable: dystopian tabletop gaming
  26. BrickItUp!
  27. Twine
  28. Olopede
  29. onetesla

The meetup would be something like “share one lesson you learned” sort of lightning talk deal to create a supportive ecosystem of maker businesses.
As for whether an actual Meetup will happen… somewhere in my copious spare time…

[edit 3/31] some ones i missed: sprout pencil

Setting up the open source Mechanical MOOC, part one

Step 2 for dumb demo, set up a site where I can post content and syllabi.
For this, I am following the popular Learning Creative Learning course and using Mechanical MOOC, and open-source version of the massive open online course software used by Udacity and Coursera and EdX and others. Their github page is well-documented and made this process a breeze — maybe 30 minutes because I had to install basic things (this is starting from a clean xubuntu installation, well, running on liveusb actually).

anndd it’s live! for the next few hours/days, at least.

Sentences highlighted are the non-liveblog, what you actually want to do steps.

  • Spin up an xubuntu liveusb… I really don’t want to try to do webdev on a windows machine
step 1: git clone

  • Install git
  • It’s a fairly old xubuntu liveusb (12.10 from lsb_release -a) so some repository 404s initially

sudo apt-get install git

Failed to fetch  404  Not Found [IP: 80]
E: Unable to fetch some archives, maybe run apt-get update or try with –fix-missing?

sudo apt-get update –fix-missing
sudo apt-get install git
okay works now.
git clone

step 2: Spin up a new instance of the heroku cedar stack

  • Needs CLI

step 3: git push to heroku instance

  • git push
    Permission denied (publickey).
    fatal: The remote end hung up unexpectedly
  • Right, I need to do the remote key thing
    cd ~/.sshssh-keygen -t rsa -C ""


  • Copy paste into and hit “Add new key”
  • cd ~/mechanicalmooc/
    git push
    fatal: ‘master’ does not appear to be a git repository
  • lol not a valid command. okay time to refresh flaky memory
    enh that is too manpage like for me to understand, try this instead
  • Well this works, hope it doesn’t mess anything up.
    git remote add heroku
    git push heroku master
  • visit site

Hrm, okay, now to fix things up

Laser-etched Sushi (nyansushi?) (aka, lasercutter settings for seaweed)

inspired by Designer Nori except theirs turned out a lot better (how did they get their seaweed to burn so white and not be affected by the humidity of the rice?)

Designer Nori.  img src [x]

recently made some sushi for the excellent cathy wu

lasercutter settings epilog 120w: raster, 600dpi, 100% speed, 5% power

step 1. coreldraw + clipart I borrowed from the internet

step 2. print to lasercutter using aforementioned settings
(without taping the seaweed down, it would go flying everywhere thanks to air assist constantly pulling air out of the lasercutter)

step 3. make all the ingredients for sushi
(rice with white wine vinegar seasoning, some raw bell pepper, a lightly boiled green onion strand, egg, and some carrots blanched for two minutes, where I learned blanche = immediately quench in cold water to stop cooking from continuing)
I didn’t try any so +Cathy Wu will just have to let me know how it tastes.

words facing up just for show! obviously no one will read something on the inside of the sushi roll…

step 4. roll it up
rice goes on 2/3 of the roll. make sure to spread the rice in the right place (just think about it carefully) and that the words are facing down unlike the previous picture which is just for show or else the words will be covered up.
Seems to fair worse when the humidity of the rice affects the seaweed.

i’m wearing a chaihuo tshirt — it’s a makerspace in shenzhen, china

Obligatory nyancat related laser thing.

Servo repair with 4-40 tap, no thanks to silly proprietary servo hardware

Hexapod now has 18 working servos again! yay.

Servo Failure modes
I didn’t strip the gears* on one of my servos from applying to much load to it (the way I expected my servo to fail), but rather stripped the threads on the servo to servo horn coupler.

*see for a good video of designing a robot, having the gears strip, and solving that problem with rubber “shock absorbers.” This video is shown near the very beginning of 2.007 Design and Manufacturing I, a sophomore build-robots mechanical engineering class.
@28:30 you see a good picture of stripped servos gears, where the missing teeth means that the servo can’t turn correctly:

Anyway, I had some issues because I thought maybe I was using the wrong size screw. The servo horns and screws and splines are all some dumb not inter-compatible between manufacturers proprietary design.

So I ordered some replacement servos off of ebay.
“Vigor VS-2 standard analog Servo VS 2 vs2”
$9.98 for 2, or $4.99 each.
Probably I paid way too much but whatever. At the time I thought $5 was really cheap for a servo (now I think $3 is more reasonable price for this servo). Bought 2/9 and delivered 2/19, not bad.

At first I thought I got ripped off and the servos were stripped, but then I looked more closely and realize that there are no threads cut into the servos:

So you can use the proprietary self-tapping screws, but I realized you can just tap them with regular ol’ 4-40 threads and use normal 4-40 screws instead of, if you ever lose the pack of proprietary servo stuff, hunting around for ages looking for an appropriate size screw.
left: 4-40 screw mates fine with servo horn. top: a 4-40 tap. right: A proprietary screw with mysterious thread count and pitch next to a nylon 4-40 screw.
Works well!

Hunt for cheap steppers cont’d: VID teardown, datasheets

Steppers I mentioned in previous post came within a few days! They’re not as small as I’d thought, but they are very flat. I bought them off of amazon by searching for “stepper motor gauge”:
6 Stepper Motor Chevy AVALANCHE V8 5.3 8.1 2003-2006 Gauge Cluster Speedo Speedometer x6
$16.5 for 6, or $2.75 each.

The inscription says VID29-02P.

Well, I decided to take one apart.

They’re geared steppers and you can see the end stop (top right) that prevents the gear from rotating and this stepper from being continuous. It has 315deg of travel according to the datasheet.

If you take it apart, you see that the four leads of the stepper go to the four poles of two coils of wire, switching the electromagnet on and off.
That’s all there is to it!

Time to find a datasheet.
Here is one for a similar one, the MR series:
which is where I get my guess of VID’s “Angle of rotation of motor with internal stop” as equal to 315 degrees from.

Here’s a note of the rather obscure manufacturers:
For instance, in our case:

Hong Kong based VID also manufacture a range of similar motors. Their motors are black, and have a black model number starting with β€œvid”.

Well, anyway.
I also decided to buy (off of ebay) some less strangely shaped and hopefully easier to couple to stepper motors. They turn out to be cheaper too!

[x] img src, ebay iawoo
28BYJ-48 – 5V Stepper Motor Datasheet
“New 1pc 5V 4-phase 5-wire Stepper Motor Gear Motor 28BYJ-48”
$8.72 for 4, or $2.18 each.

Those should get here in two weeks. It’s nice to just order fun things ahead of time and feel like I am getting good deals.

That’s all for now.

References “Quick Start for Beginners to Drive a Stepper Motor”

2dof minimalistic servo arm, now with mapped values + code

values actually mapped correctly = some semblance of control. mapping painstakingly / experimentally determined
the setup

actually very difficult to write words even with the arm controller (versus twiddling some potentiometers to control the arm), because the potentiometer to servo mapping isn’t precise and there’s a lot of slop (e.g. look at the dead space around the screwdriver)

time elapsed: probably 1 hr including trying to figure out how to draw things and documenting ^^ (~40 minutes to code this and map the values)

 * @file: RC control of servo
 * @description
 * theta1 = bottom joint pot value, theta2 = top joint pot value
 * these were experimentally determined,
 * I had one leg of pot connected to sig5v, the other to a voltage
 * divider setup with a 1kohm=R2 and being read to A0 or A1 respectively

#include <Servo.h>
Servo servo1;
Servo servo2;

int theta1;
int theta2;

int map1;
int map2;

void setup()
//    pinMode(1, INPUT);
//    pinMode(2, INPUT);

void loop()
  theta1 = analogRead(A1);
  theta2 = analogRead(A0);
//  map1 = map(theta1, 163,380, 0,130);
  map1 = map(theta1, 163,360, 0,130);
//  map2 = map(theta2, 1017,275, 0,160);
  map2 = map(theta2, 1017,264, 3,150);
  Serial.print(“theta1 “); Serial.print(theta1);
  Serial.print(” map1 “); Serial.print(map1 );
  Serial.print(” theta2 “); Serial.print(theta2);
  Serial.print(” map2 “); Serial.print(map2);

Continued thoughts on online edtech startlols

Formalizing why my idea is a valid one (a good plan before spending several months / hundreds of dollars on it).

Maker culture isn’t turning to Sand Hill funding because this experience doesn’t scale or grow at Paul Graham rates. The experience, for each child, will personal and meandering. Great mentors can guide, good materials can enable, but there’s nothing to automate.
I’ve felt the incredible rising tide of Maker-Ed over the last 10 months, but that hasn’t made my work with actual kids move any faster.
LittleBits, MakeyMakey, and other funded projects in this space have found success producing a discrete tool/play kit that a learner can continually and non-linearly poke at. If someone shows me a graduated sequence of LittleBits learning targets and an web quizzes for assessing them, I will build a banana triggered junk kicking robot just for them. –andrew carle

Hmm. This criticism is super-concerning to me, because I’ve heard a lot of similar sentiment (fully kitted / canned labs) from friends of mine (e.g. from hall alum feldmeier, founder of openmusiclabs (hackaday)) I respect.
Maybe this is true. On the other hand, I can’t count the number of people I’ve had approach me or MITERS who are interested in making things but not quite enough and seem to just need a little guidance. Similarly, for myself, I found it useful to build something cool/awesome in order to learn the skills (not just technical skills, but also skills like how to find resources online, finding the courage to ask questions, how to ask questions coherently… okay still working on that last one) I needed to go forth and build my own cool projects. For learning, there’s no shame in copying as long as you credit your sources. No need to reinvent the wheel just yet.

[edit: 3/24/13] After talking a bit with +Josh Gordonson (blog / working on olopede), I have some further thoughts:
“Just do it.” So what. So it’s not a kit that empowers people to build everything ever. So what if by its very nature the kit is rather formulaic. There is still value in exposing people to cool things and showing people they’re capable of building and understanding these things. So maybe it’s not the most innovative / experimental online learning platform out there (right now I’m planning on following the learning creative learning’s path of not writing my own platform and really on tools existing out there). And even if I fail (to make a sustainable business), I will still have accomplished something useful to other people and to myself. Better than sitting here and fretting — even if I fail, less of a waste of time to have attempted to engineer this than to constantly research.

What troubles me about many of the criticisms of Khan Academy is that they are positioned against alternatives that are relatively scarce in the real world. Are Khan’s videos essentially lectures? Sure. But they’re better lectures than many students will ever get from their classroom teachers. Are there more effective ways of teaching some students? Sure. But many students (many, many, many students worldwide) will never have access to those teaching methods at any price, never mind for free.  —Michael Feldstein

I’ve been working in a public classroom for one of my classes, and teaching is hard. More on that in later posts, but doing things like asking kids “what do you think that is” (engaging them) versus “this is what’s going on” (lecturing them) is something that takes effort. Is this something that is transferable to the online world (because currently I only have udacity-style in mind, which is basically lecture based with “finger questions,” mid-lecture questions that check understanding and you raise your finger to show your asnwer)? Does it matter if you don’t have 30 kids compelled to be there and instead are addressing self-directed learner? Not sure.

I’m learning toward KISS — keep it stupidly simple. Do a bare-minimum, replica of existing work just cobbled together, for Aug 31. Hopefully that will give me enough momentum / convince people to help me to make it seem definitive that I can do this instead of landing a job.

Also, such an excellent image from that article:

obama marshmellow canon

Also, today I talked to Prof. Mitch Resnick when Dale Stephens (Uncollege) came to give a talk at the media lab. More about that later too! Briefly, there were some provocative comments, such as 
  • “If/When will an unschooler ever get a Nobel Prize in Science, and how do we get there?”
  • And I asked the same question mentioned earlier by another blog: where do we stand, university’s value to students versus university’s value to society? (university as public good)
  • Education becoming like a game, with loopholes, for premed and finance students
  • and a key thought that was surprising to me back when I first heard of it: common core (more rigid curricula) as a detriment to self-motivated learning. This is because the teachers don’t have time to be flexible and accommodate things, for instance some people from Harvard/MIT/Wellesley coming in and teaching about engineering and the design process.
Also, LOL, a comic about the increasing frenzy surrounding Massive Open Online Courses:

MIT summer housing research

$160/week for a single (one person, one room)
$140/week for a walk-though single (one person, one room)*
$120/week per person for a double (two people, one room)

 * A walk-through single is a room that is accessed by walking through someone else’s room, or that someone must walk through to get to her room.

-> 12 weeks = $2160 to $1680
Single 2171
Double 1910

It will cost $722 or $622 per month, depending on the room. You do not need to rent for all three months.
$1866 to $2166 for 3 months


These approximate prices are for the entire summer and include food. πŸ™‚
Quad: $1050 
x2 = 2100, except pika has a waiting list and probably only I can get in, not my friend (not from MIT)…?
Triple: $1200
Double: $1450
x2 = $2900, again kind of risky
Single: $1800

rough it out: free
TAing @ $16/hr, 20hr/wk, Jun10-Aug10 = 61 days not including end date (9 weeks) = $2880. Eek. Haha. Time to start selling things on etsy or something…
Possibly factors: novelty (not stay in same place again)
I’ve been spending this week mostly on applications and looking for funding. In one way, mathematically, this is a good idea — spend a bit of time to get thousands of dollars versus work all summer to get the same amount of money. However, I am wary that I’m spending too much time on this — time is money too.
Alternative ways to make money: finish persistence of vision yoyo and sell some. This would happen at the end of May. Con: takes up precious time, again.

Update 4/18/13: Got on the pika waitlist, so… time to look for other options
EC undergrad housing, 2171/summer, May 28 – August 11 (75 days).
~870/month (30 days)

MIT Guest housing, $38.50 per night,
$1154/30 days

x12 weeks, 120/wk, $1440 (480/month)
x2 people, $2880

Frat housing
Looks like about $1700 each for the summer for a double. $1350 ea. if we are okay living in a quadruple.