## Sunday, March 31, 2013

### 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

http://www.ispydiy.com/2012/08/my-diy-envelope-laptop-case.html
 [x] img src
that made it seem so easy, like something i could finish in 15 minutes

well
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: http://youtu.be/lDiTi6C-66Q?t=2m16s 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

## Saturday, March 30, 2013

### 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).
http://www.kickstarter.com/discover/cities/cambridge-ma/funding?ref=more#p1
(sadly, you can't sort by both "boston" and "technology"

http://goo.gl/0092S

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 funded﻿: (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:
http://www.kicktraq.com/projects/onetesla/onetesla-a-diy-singing-tesla-coil

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
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

## Thursday, March 28, 2013

### 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! http://cryptic-sea-7936.herokuapp.com/ 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
https://github.com/p2pu/mechanicalmooc/wiki/Getting-it-Running#wiki-heroku
step 1: git clone https://github.com/p2pu/mechanicalmooc
• 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

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 https://github.com/p2pu/mechanicalmooc

step 2: Spin up a new instance of the heroku cedar stack
• https://devcenter.heroku.com/articles/cedar Needs CLI
• Install heroku command-line interfact
https://devcenter.heroku.com/articles/heroku-command
https://toolbelt.herokuapp.com/
wget -qO- https://toolbelt.heroku.com/install-ubuntu.sh | sh
• heroku create
• I get this instance spit out at the end:
http://cryptic-sea-7936.herokuapp.com/ | git@heroku.com:cryptic-sea-7936.git
step 3: git push to heroku instance
• git push git@heroku.com:cryptic-sea-7936.git
Permission denied (publickey).
fatal: The remote end hung up unexpectedly
• Right, I need to do the remote key thing https://help.github.com/articles/generating-ssh-keys
cd ~/.sshssh-keygen -t rsa -C "your_email@example.com"
cat id_rsa.pub
• Copy paste into https://dashboard.heroku.com/account and hit "Add new key"
• cd ~/mechanicalmooc/
git push git@heroku.com:cryptic-sea-7936.git
fatal: 'master' does not appear to be a git repository
• lol not a valid command. okay time to refresh flaky memory
http://gitref.org/remotes/
enh that is too manpage like for me to understand, try this instead
http://git-scm.com/book/ch2-5.html
• Well this works, hope it doesn't mess anything up.
git push heroku master
• visit site http://cryptic-sea-7936.herokuapp.com/
Hrm, okay, now to fix things up

## Wednesday, March 27, 2013

### list of hackerspaces, 2012 vs 2013

 2013
 2012
Not as dramatic growth as I would've expected :)

 something interesting to compare to -- people taking Learning Creative Learning as of the third week  of class or something

## Tuesday, March 26, 2013

### 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

Nyansushi?
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 http://techtv.mit.edu/videos/10523-what-is-design-an-example 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!

Anyway.
Time to find a datasheet.
Here is one for a similar one, the MR series: http://clearwater.github.com/gaugette/resources/mcr/2010410104720473.pdf
(mirror)
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 “vid”.
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

http://electronics.stackexchange.com/questions/60969/stepper-motors-stride-angle
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

http://www.freescale.com/files/microcontrollers/doc/app_note/AN2974.pdf "Quick Start for Beginners to Drive a Stepper Motor"

## Thursday, March 21, 2013

### 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);
Serial.begin(9600);
servo1.attach(2,500,2400);
servo2.attach(3,500,2400);
}

void loop()
{
//  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);
servo1.write(map1);

servo2.write(map2);
Serial.print("theta1 "); Serial.print(theta1);
Serial.print(" map1 "); Serial.print(map1 );
Serial.print(" theta2 "); Serial.print(theta2);
Serial.print(" map2 "); Serial.print(map2);
Serial.println();

delay(20);

}

### 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).

http://hackeducation.com/2012/11/21/top-ed-tech-trends-of-2012-maker-movement/
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:
 http://info.p2pu.org/2013/03/16/open-learning-webinar-the-proof/

## Sunday, March 17, 2013

### braindump, 3D Printing Research (from a year ago)

Last summer (while I was an intern at fitbit) I did a bit of research on 3d printers while considering getting a solidoodle, so this is about year-old information

### miniature things research (tiny steppers!) / start-lolling, start-trolling, start-rolling

stepper motors
I started looking into how tiny and cheap steppers can get, since micro servos are in the $2-3 range, and holy lady hexapods they can get tiny. More info here. Turns out most tiny steppers come from vehicle dashboard instrumentation. To actually buy them you don't turn to mcmaster http://www.mcmaster.com/#stepper-motors/=lwy84g Instead, a search for "nano stepper motor" reveals this: More info here, including the fact that this stepper can be driven directly by an Arduino. On amazon, these cost ~$2-3 each as well. (search for "stepper motor gauge").
I just order 6 for $16.50 to have some hand to play with (randomly ordering the micro-servos a while back turned out well); we'll see how this goes. So, upcoming tiny stepper gantry? Some more reasonable 15 cm ones cost ~$15 (vs the price on mcmaster...)

flying things

### weekend project: minimalistic servo arm

There's a video of it in its final state, with its multitude of issues. *sigh* one day I will actually finish a project. Only the first and last 5 seconds or so are interesting. Cost: ~$6 for the two microservos (!! so cheap), plastic is free, then the board+microcontroller battery is$25+$15+free (probably$10?).

After building hexa-rideablepod, I have definitely been more inclined to daydream about small or fold-able or compact project.

I should update my project todo list.

Anyway,
I started at ~8pm on Saturday and finished ~3:30 pm on Sunday (and yes, I did sleep a bit, as well as watch an anime movie (Summer Wars) ...

 what the cloud looks like in the future

... and spend a lot of time reading about inverse kinematics and poking at IK code I never ended up using).

I was inspired by http://www.instructables.com/id/Robotic-Arm-with-Servo-Motors/?ALLSTEPS

The code looks pretty straightforward.
 
// Given theta1, theta2 solve for target(Px, Py) (forward kinematics)
void get_xy() {
  actualX = a1*cos(radians(theta1)) + a2*cos(radians(theta1+theta2));
  actualY = a1*sin(radians(theta1)) + a2*sin(radians(theta1+theta2));
}
I was a bit confused by the definitions of the variables, since I haven't done kinematics in a while. In the forward kinematics part it is essentially saying:

 measuring the servo spline outer diameter in order to create lasercut female splines on my parts instead of using the proprietary servo horns. I started around this time. I swear I spent like 30 minutes trying to figure out how many divots it has (21) before just trial-erroring it, lol.

It gets to be pretty late in the day after I try to struggle to remember kinematics.
Here are some beautifully written kinematics notes I found linked from stackexchange question on drawing robots (robotics stackexchange! i'm excited).

Well, crap. I hesitate -- do I want to try to get something done and present a project or not? I eventually decide (and with some support from the awesome Jessica Artiles) that I may as well get more feedback on my ideas. What is there to lose?

Thus, I emergency hot-glued some potentiometers onto pieces of plastic and used that as my control ( a simple mapping of potentiometer values to servo values is all that's needed) instead of writing IK code. This arm controller design was inspired by http://www.maxjusticz.com/a-miniature-robotic-arm-controller/.

 img src my design inspiration, except mine was jankier and used more hot glue

 near the end of the designathon
I didn't even have time to map things correctly, because I thought the presentations began at 5pm but actually they began at 3pm.

The lasercutter files looked like so:
It's hard to see the cuts. But the pots have flats on their shafts, so the pot arms have semicircular holes that are tightly fit onto the pot shaft to couple rotationally. And for a minimalistic design, the robot arms have servo splines cut into them so they mate directly to the servo.

I had the most issues trying to make a press-fit bracket for the servo so that I could couple it to a base. The sides of the servo weren't particularly flat so the rectangular brackets always broke on installation; I ended up with a C-shaped bracked design.

 a frontal image
Also, the servos are amazingly torque-ful. I thought the base would be enough to hold it down but I ended up adding tape so that the servo arm wouldn't swing itself around.

Also to fix, I actually need to build a platform so that the base is heavy enough that the servos don't push it around and high enough that at zero degrees the width of the servo arm doesn't cause it to hit the ground.

I also actually did calculations for the servo, or rather used a calculator online, to verify the servos would handle the sharpie weight. Not that I had different servos or anything. (screenshot below)

Oh, another issue I ran into, the servo.write() arduino library uses modulation from 544us to 2400us, while the microservos used 500-2400 us, which gave me this issue where the servos wouldn't go all the way down to zero degrees when I used myservo.write(0). I took a quick look at "arduino-1.0\libraries\Servo" and found out thatyou can specify these min/max values when you initialize the servo, e.g.

 attach(pin ) - Attaches a servo motor to an i/o pin. attach(pin, min, max ) - Attaches to a pin setting min and max values in microseconds 

There was some other funky issue with trying to read a sensor while the servo was drawing power. Turns out I just need more delay in my loop.

Can't think of anything else for now.

Material Costs
ebay $11.88 "4x SG90s 9G CYS micro servo motor RC Robot Helicopter Airplane Car Boat + Horns" so about$3 per servo

The servo specs: http://www.servodatabase.com/servo/towerpro/sg90
 Pulse Width: 500-2400 µs sg90

Current Status:
I lost the code, and I broke some of the lasercut pieces, (the usb port for programming the arduino also seems to create a lot of sensor noise and the servo arm kind of did crazy robot arm thing and killed itself) so right now I re-lasercut  pieces and am re-writing the code. Should be up within a week.

===================================

#### Follows is a live blog of me working on drawbot:

===================================

ebay $11.88 "4x SG90s 9G CYS micro servo motor RC Robot Helicopter Airplane Car Boat + Horns" so about$3 per servo

confirmation that 9g micro servo can indeed make robot arm:

okay yay let's do some math
thanks society of robots

alright, now let's see some real specs on these micro-servos:
Stall Torque at 4.8 volts = 22.2 oz/in (1.6 kg/cm)
aww... so cute (compare to the 7 to 15 kg/cm ones used in "small" robot arms: http://www.nex-robotics.com/robotic-arm/robotic-arm.html)

So what are the tradeoffs? With a longer robot arm length, I get more range, but then I suffer torque-wise.

Also, need 4 dof -- one for the pen to move up and down.

===
7:47pm
some research into simulating robot arms online..
http://wps.aw.com/aw_young_physics_11/0,8076,898588-nav_and_content,00.html

my initial thought was to use processing, but oh hexapods java applets >__<

okay the guy next to me at the hackathon, idk his name, says i should just write it in html5
[edit: it may have been vincent xue]

excellent plan, learn html5

mmm kinematics libraries http://kineticjs.com/

wah html5 games
http://raptjs.com/
okay let's not get too distracted

hrm kinematics in flash
===
http://www.societyofrobots.com/robot_arm_tutorial.shtml

frick
i should catch up in 18.06, perhaps
http://commons.bcit.ca/math/examples/robotics/linear_algebra/index.html

==
okay, assume some weights
1.18 g/cm³

okay let's make up some dimensions for a link length
4x16x3 = 192 cm^3 * 1.18 g/cm^3 =
226.56
thanks dot-gridded metric notebook and google

hrm, so about 1/5th of a kg. Wait what? that seems wrong.

oh units -> 0.3cm thick, so = 22.7 grams.

(from actual measurements:
15g for a 3*50*76 mm chunk, or 1.32 g/cm^3

okay now for
pre-built calculator!
:P
 okay not operating near stall torque, that is good
(conversion N m to kg cm is about x10, if you let gravity ~10 m/s/s)
==
8:30
okay, screw this, I am going to CAD some stuff
later: end up not CADing anything
==
3:18
One anime later, and back to staring at robots.
i start watching youtube stanford lectures but am too sleepy
http://www.cs.unc.edu/~jeffi/c-space/robot.xhtml mmm canvas, 2010 2d robot arm simulator

hmm GUI via processing
http://luckylarry.co.uk/arduino-projects/arduino-modifying-a-robot-arm-part-2/

oh! excellent written documentation

===
day 2
haha, still here. i'm so sloowwww at building things, all the other teams are so cool
okay i'm working by myself because i'm weird like that

eww, the servos are doing funky things where servo.write(0) doesn't seem to go all the way to zero. let's compare. hitec311 and sg90.
http://www.servodatabase.com/servo/hitec/hs-311
 Pulse Width: 500-2400 µs sg90

 Pulse Width: 900-2100 µs hitec311

hrmmm.

bam,
arduino-1.0.3\libraries\Servo\Servo.h

attach(pin, min, max  ) - Attaches to a pin setting min and max values in microseconds
default min is 544, max is 2400

==
Adam Libert, DIY waterjet and crazy grad student, drops by and shows me cool robots:
http://medesign.seas.upenn.edu/index.php/Courses/MEAM520

==
serial monitor output:
º’j¤ º’jP ºŠjR ºŠjR º’jT ºŠjR ºŠjR ºŠjT ºŠjR º’jR ºŠjP º’jP º’jT º’jR º’jP º’jR º’jP º’jR º’jR ºŠjR º’jR º’j

Exciting, when I am commanding a servo, it pollutes the analogRead.
Well then.

Oh, I just needed to increase the delay (was using 1). Hmm. I'm not even writing to the servos. I wonder why initializing the servo means the serial loop can't run fast enough.

==
how the heck does a kit for this not exist already?
$250, wow. == whee it's 3 pm and i decided to pitch because I HAVE NO SHAME. :D It's amazing what having the support of a friend can do for you. ### MIT Founders' Skills Accelerator 2013 application in non-form format Ugh, the Founders' Skill Accelerator application is in this dumb form format, where you have to fill out required questions on each page before seeing the rest of the application. I put in dummy answers and then compiled all the questions the application asks as of now. In neat google doc form: https://docs.google.com/document/d/1dgtuI_cpWE-TWoLtpPvW_wsbbLbqRnEQJoWFkgohl-c/edit?usp=sharing I copied it below as well, but too lazy to fix the formatting. == #### http://entrepreneurship.mit.edu/fsa/faqhttp://www.tfaforms.com/forms/resume/275181 Teams should commit to work in the FSA office space for the duration of the summer (June 1-August 31), and present at the Demo Day on September 7. Page 1 Deadline: Friday, April 5, 2013 at 5pm EST Bio (2-3 students) for each of us How long have you known each other, and what have you worked on in the past? (Include past work done on this project, if applicable.) Will the team member work in the FSA space Room E40-160 in Cambridge, Mass. for the duration of the summer (June 1 - Aug 31)? Page 2 Your Project We call each team's work a "project" to emphasize the educational nature of the accelerator. • What problem are you trying to solve through your project? • Tweet us your elevator pitch -- give us your elevator pitch in 140 characters or less. • Page 3 Proposed Milestones (aka how your team earns up to$20K!)
What do you want to achieve this summer? We will work with you to create rigorous yet achievable milestones, but we'd first like to hear from you. Where do you want your team to be by mid-September regarding customers, product, team, and finances? (list 2-5) For more explanation about milestones, including examples, please go to http://entrepreneurship.mit.edu/fsa

Proposed Customer Milestones (list 2-5 for each)

• customers
• product
• team
• finances

http://entrepreneurship.mit.edu/fsa/milestones
Page 4
What inspired your team to get together and work on this project?

Who do you view as your competitors, and how do you differ from them?

Who is your target customer? (Hint: "Everyone" is not the right answer.)

Have you received any funding (including angels, family/friends, personal dollars invested, etc.)? Do you have any customers? (These two questions help us gauge your starting point, so don't worry, there is no "wrong answer.")

We will have a lot of applications for this program, so choosing our final teams will be tough. Why do you think you should rise to the top? What sets you apart from other teams?

==
Can I work out of IDC space instead (the MIT-SUTD international design center is a co-sponsor of this) of the E15 space?
Incorporation of media (e.g. video) into application?
Alternative resources (because way to hang by a thread until May 1st)?

Key dates:

• Due Friday, April 5 at 5pm. (week after spring break)
• Notified by May 1st.
• Work in space for duration of the summer (June 1-August 31), and present at the Demo Day on September 7.

Notes:
A select number of teams (in 2012, there were 26) will be interviewed in person during the week of April 22. Of the teams interviewed, we expect to select 8 teams for FSA 2013, but the FSA organizing team has full discretion over the number of teams selected.

So... odds are not great. Stipends are nice. Stipends will feed me. Maybe I should look into trying to get no-strings attached grants from places?

## Saturday, March 16, 2013

### Hexapod conference? how to plan a conference budget?

I applied to the deFlorez Fund for Humor at MIT. The application deadline for grants over \$1000 was due at midnight, and at around 10pm I decided to apply for funds for a hexapod conference.

I should hear back by the end of MIT spring break (the 30th).

Funding decisions will be made approximately two weeks following the application deadline. If an award is made, disbursement of the award will take place once sufficient funds have been secured to hold the event.

If they fund this, it will be hilariously awesome. However, the application is so hilariously rushed and badly written that I am actually really embarrassed. It was so much fun writing it though. The coherent parts were written by the lovely +Julia Hopkins (http://fluidarchive.blogspot.com/), including this beautiful part:

Please explain in one or two paragraphs how exactly this event fits the de Florez Humor Fund mission of "impressing students with the importance of humor in all aspects of life, both personal and business."

Let’s face it. An MIT student’s personal life is their work life. Too few are prepared to find the humor in this, or prepared to acknowledge such humor exists. This conference epitomizes silliness in research, silliness in personal projects, and silliness in how we envision the technical world around us evolving. Moreover, it highlights the importance of this silliness in a student’s daily life. The concept of a hexapod, the concept of investing time and resources into something that, in the end, probably won’t change the world (unless you build it several stories tall and figure out how to give it a Godzilla complex), resonates with many an MIT student. This conference is to help them both acknowledge and celebrate all of the things in their research, classes, personal lives (for those that persist in imagining they have one, in any case), and business which have not gone the direction they anticipated, or which did not provide as much of an impactful result as they were envisioning.

I would try and explain the humor of wrapping all of this up in a metaphor of hexapods and then go on to wax eloquently (or perhaps just wax) about the philosophical implications of how a project which has gone nowhere can still impart necessary skills and life lessons, but that’d be spoiling the fun of it. You should come see for yourself the wonders of dancing hexapods, the hours of toil put into this utterly silly contraption, and experience your nervous laughter as this parody evolves into genuine humor acknowledging all of the ridiculous things humans do which, somehow, make the world a better place. We’re just not sure how yet.

Well, anyway.  How do you plan a conference?

Well, you decide on a mission (yes, conferences have missions) and then make a budget. This is a most excellent guide on missions and general conference thoughts: http://ctb.ku.edu/en/tablecontents/sub_section_main_125.aspx

e.g.
The field needs a conference.  There are several possible reasons for this:
• The field may be a new one, and still lack a clear identity.  A conference could bring together the people who are building it, and help to define it.
• The field may not be cohesive.  People in it may not know one another, may disagree on methods or other issues, or may simply not realize how many others have similar interests.  A conference could bring them together and create networks that would expand and improve the work.

The mission of this conference would be to promote silliness at MIT.

Here is the budget I ended up with:

 . Item Cost Comments . venue rental fee connections (held in the N52 IDC space, using equpiment there) . food and beverage fee 300 (can be acquired from dumpsters but kind of sketchy) . transportation & lodging scholarships 500 to help people make it here . A&V, recording, livecasting equipment 150 . speaker fee bribe with cookies . activity fee 100 (lasercut hexapod material - bristol board) . miscellaneous fee 100 . prizes from reuse . . Total 1150

(budget table in neater formatting here)

And here is my (rambling because I had no time) proposal:

The conference schedule (tentatively planned for May 4th) would be

9 - 9:30 registration, breakfast
9:30 - 10 keynote speaker
10:15 - 11:15, break, 11:30 - 12 five-minute lightning talks (+ 5 minutes questions), nine total
12 - 13 eat food and make hexapods (invite general public, including kids)
13 - 14 hexapod dance-off, other hexapod competitions (e.g. fastest?)
14 - 17 conference talks about specific topics (e.g. the use of hexapods in educational kits, in adaptive terrain traversing (climbing trees, over rough ground), in millirobotics)
17 - 18 pm Poster session and demonstrations, appetizers

For reference, prior work:

http://youtu.be/pXMnbNoccgA?t=49s

http://ieee.scripts.mit.edu/urgewiki/index.php?title=S2012_-_Hexapods_and_Other_Cool_Things

http://katygero.wordpress.com/2012/07/17/hexapods/
The rapid fabrication hexapods we made during the last reading group session.

Hexapod Demonstration II from Katy Gero on Vimeo.

## Tuesday, March 12, 2013

### Khan Academy has hands on projects now / general web roundup

Hands-on projects at Khan Academy? So it begins.

In fact, there's even a "lead of applied learning" position at Khan Academy (ran across this while browsing the SXSWEDU schedule)  who is "focused on leading and supporting a variety of strategic initiatives and creating project based learning content.
==
Vibrobots / brushbots: an alternative to using toothbrushes (and cutting up new ones or something) for a class is to use business cards! See howtoons: "Introducing Gami-Bots!". Pretty awesome.

==
In other news, I am going to linkdump from facebook because it's hard to search through facebook posts.

There's actual less-derpy flying hexapods now:
Now they just need to write the code to make it dance... Also apparently going to be on kickstarter soon, like everyone else's projects ever.

==
Additionally, there's a simulation game for making robots covering things like drivetrain tradeoffs now/soon/in-the-making! Exciting.
http://www.kickstarter.com/projects/647436241/logicbots

==
I discovered pinterest, or rather pinterest for hexapods:
http://pinterest.com/search/pins/?q=hexapod
2009? How did I miss this? ^^

http://pinterest.com/search/pins/?q=lasercut+mechanism
 it actually walks! http://www.kineticcreatures.com/pages/modding-with-lego
==
That same term, lasercut mechanism, on google pops up a BS in MechE thesis by one of my classmates, @JoshRamos
http://dspace.mit.edu/bitstream/handle/1721.1/68917/773695779.pdf?sequence=1
It's a paper about trying to make a lasercutter. Has good background information, so goes on my toread list.
According to +peter krogen on facebook,
Peter Krogen · mmm laser cutter made of legos Its a shame he didn't build it in 2012, then he could have used the new 2w 445nm diodes (which have much better beam quality) that were available a few weeks after he turned in his report.
==
Additionally, discovered this on a list of startups at the ongoing San Francisco Hardware Meetups, a folding portable kayak:
http://www.orukayak.com/
 origami kayak!
==
Finally, I am going to be addicted to this site, I just know it. There is now a robotics StackExchange site:
robotics.stackexchange.com