Category Archives: Hexapods

hi 2016 (2 servo drawing robot arm, tripod gait 12 servo hexapod, visit to NASA, quadcopter tuning, etc.)

hm, haven’t updated in a while.

i built a lot of robots with parents over the winter break. i built a robot arm and refreshed on inverse kinematics; more specifically, make sure your servos are rotating as you expect: IK goes counterclockwise since angles increase that way, but your servos may increasing in a clockwise direction… a simple map(theta, 0, 180, 180, 0) will fix your problem if you catch it.

2016-01-01

processing takes in x,y coordinates drawn on the screen and spits them out to arduino over serial, which does the inverse kinematics and spits out the theta values to the servo

https://github.com/NarwhalEdu/CopyCat/blob/master/Code/basicsIK/basicsIK.ino

or for the one where it draws what you draw on the screen, https://gist.github.com/nouyang/b312b9ea5c67baa0c914

also tried to face.

it does not face well, in part i have derpy three year old code

face3

this processing code takes a lot of processing libraries. thresholds image, performs canny edge detection, then a walking algorithm (look at each black pixel by scanning image in x and y, see if neighbors are black as well, then walk along that pixel) to turn the edges into vectors. then output to robot, but robot is limited in resolution (arduino servo library) and cheap hobby servo overshoot.

below you can see preview in python.  (basic code, I basically copied the output from processing into a text file and  added some python code to that to plot the values)

is to check image is within the working envelope of the arm. IK is fixed with arm “up”.

face2

faceservo

problem of walking algorithm: adds a box around the image. irritating. need to rewrite code. looking into open cv.

i also rehashed my hexapod project with 12 servos and popsicle sticks

hexapod

basically this https://github.com/nouyang/18-servo-hexapod/blob/master/arduino_may13_2011.pde

but modified to work with the servo configuration on the rectangular robot, and added code to allow you to step through the gait with “j” and “k”: https://gist.github.com/nouyang/d9b6474e3ee412b9b05b

need to implement the other gaits; also, this moves so smoothly, envious, but they have lasercutter :3

worked on quad, now stuck at calibration stage 😡 because i have not built quad before, i could not push through this in a day or two unlike the drawing arm and hexapod.

quad

 

made from a sad clothes drying rack we took apart

 

 

 

transmittercable

we couldn’t find the original cable for the transmitter, so we connected the ports up with a FTDI -> USB cable as per http://psychoul.com/electronics/how-to-make-your-own-usb-cable-for-hk-t6a-calibration

zero

used http://www.sgr.info/usbradio/download.htm and calibrated my servos to zero… took a while to realize it *can* and *should* read the current values, guess my wires were loose, but the values because a lot easier to input. used the kk2 screen to fix some controls that were reversed from what the kk2 expected (left = left and not right, etc.). zeroed all the values on the kk2. turns out (minus the flipping controls) I could zero just as well on using the trim knobs on the controller itself.

went to visit NASA space museum in houston. they had little robot that made and served you froyo. adorable.

nasaicecream

also, some regal looking hexapods in the actual NASA workplace.

 

nasarobot

at MITERS I got a robot arm working with lots of help from MITERS / London Hackerspace / john from BUILDS. For robot arm competition. http://robotart.org/

i’m now robot art-ing. here is using Fengrave on a black and white image with appropriate offsets to produce gcode (well, limited to G0 and G1 commands)

fengrave

robotdrawing

face code still derp. (streaks are because i wrote gcode translator, and it goes to x,y,z position instead of x,y and then z). too many x,y points. draws slowly.

face

michael made crayon extruder (=metal tube + power resistor) and also pen mount. crayons = hard to control flow rate. started making square, then pooped out a lot of melted crayon. alas.

crayonextrusion

learned a lot of patience dealing with old manuals, 20 year old operating systems / controllers. main issue turned out to be a dumb calibration assumption (robot had arrows; should have ignored them and used indentations instead).

https://github.com/miters/gdmux gcode -> V+

also, i learned about oscilloscope rs232 decoder! had to invert to get it working properly (zeros are high in rs232?). scope ground, tx line. bam, now you can check whether you are actually transmitting all the carriage return and line feeds you need…

2016-01-13

currently: reading up on image processing. openCV. http://web.cs.ucdavis.edu/~ma/SIGGRAPH02/course23/notes/S02c23_3.pdf

terse update. more details available if questions exist.

many thanks to my parents for being excited and not jaded

boston winter 2015: it snowed a lot.

snopocalypse? snowmaggedon?

Jan 27 2015 snow
Jan 27 2015 snow

Here in Boston, it didn’t snow at all the last few months, and then suddenly it snowed a lot (90” over the last 30 days).

Here are some sweet graphs from http://weather.ou.edu/~splillo/misc.html

http://weather.ou.edu/~splillo/misc.html Samuel Lillo
Source: http://weather.ou.edu/~splillo/misc.html Samuel Lillo
BOS30snowp
Source: http://weather.ou.edu/~splillo/misc.html Samuel Lillo

On the plus side, I’ve now met my neighbors (since they’re outside shoveling for hours). At this point, we just throw the snow up as high as we can onto piles of snow. There’s nowhere to shovel to snow to…

20150211_030924
when the snowbanks are higher than you, where do you shovel snow to?

I’ve also made new friends and spent quality time with my roommates. We all co-work, since everyone is working from home because our city cannot handle the snow. *

20150209_185702

* I come from Georgia. My Boston friends were laughing last year about Atlanta shutting down due to a few inches of snow. WHO’S LAUGHING NOW HUH? 😛 My Alaskan friends tell me our Boston snowfall is normal for them, but their cities are built to handle it.

Here is a large icicle.

20150210_151307

It later fell and broke the railing/steps on our side-access porch. o__o Apparently, falling icicles do kill people. I’m glad no one died from our icicles.

Here are some more pictures of my poor bike. <3 bike, I will spend $$ and give you a professional tune-up after winter is over.

20150215_004425

Biking in boston is a struggle right now. The major streets are passable, but all the bike racks are very buried. For instance, at wework south station, they admonished me for locking to the railing I didn’t need to step in chest-high snow to reach. To add insult to injury, when I got out of work the railing was blocked anyway by trash bags. :/

bike at work on top of bike racks
bike at work on top of bike racks that are buried in snow

Here is my bike after the valentine’s weekend snowstorm. i left it overnight on top of a snowpile in order to lock it to something. When I left, I had a “where did I lock up?” moment. It was well-camouflaged.

20150216_202551

here are some pictures from my friends

mt. albany street snow farm

mt. mit, mt. simmons, mt. albany
back when it was “just” 3.5 stories tall.

mt. mit, mt. simmons, mt. albany, mt. cambridge, who knows

view from the top
view from the top

miters

There were some silly snow vehicles: fansled aka meloncraft, ebike-ski, and scooter-ski

For technical details / build reports, see

around the web

our mayor is flummoxed

Walsh: “I don’t know what to say to anybody anymore. Hopefully it will stop eventually”

Turns out the National Weather Service meteorologists are humans and not computers

“NEXT CHANCE OF WARMTH: SOMETIME SPRING INTO SUMMER:

Source: https://twitter.com/stannenb/status/566975835316690947/photo/1
Source: https://twitter.com/stannenb/status/566975835316690947/photo/1

“SADLY JUST CONTINUED EXCEPTIONALLY COLD WEATHER … NO END APPEARS IN SIGHT”

Source: https://twitter.com/BostInnoCity/status/567379898059485184
Source: https://twitter.com/BostInnoCity/status/567379898059485184

(i wonder why they have ellipses… AND ALL CAPS… is it for maritime radio, which I’ve now spent hours listening to … for their text-to-speech synthesizer… trivia, maritime radio weather reports have three voices since 2002… here are some voice samples via NOAA “Voice Improvement Processor” … listening to it brings up salty memories for me)

weather is happening

https://www.facebook.com/weatherishappening
https://www.facebook.com/weatherishappening

He just appeared on WMBR too. http://wmbr.org/m3u/Brainworms_Radio_20150213_1900.m3u at 24 mins in. If you want your daily dose of Angry Boston Weather Preacher Dude.

train through snow

https://vine.co/v/OP9YFebzX27

everyday i’m shovelling

MBTA quick reference map

Source: https://twitter.com/SaraMorrison/status/567111295552335873/photo/1
Source: https://twitter.com/SaraMorrison/status/567111295552335873/photo/1

Note: I dug out some of this from https://twitter.com/hashtag/BOSnow

highway signs with a boston accent

Source: 5wcvb ABS news? http://www.plengegen.com/blog/genetic-forecasting-cell-biology-experimentally-validates-functional-mutations-complex-disease-sequencing-studies/
Source: 5wcvb ABS news?

build a snow igloo, then rent it out on airbnb?

https://www.airbnb.com/rooms/5195545

Screenshot from 2015-02-17 00:54:51

PSA: Be careful. Turns out collapsing snow caves can kill you by asphyxiation. This happens when snow plows don’t realize it’s a snow cave instead of a snow bank and dump tons of snow on top of your cave. Then you die. So make sure to stick a flag with a picture of a human on top of your snow cave, and don’t make it on the side of the street.

weather forecasts

predicting the future is hard. here are some good websites to help you

howmuchwillitsnow.com

howmuchwillitsnow.com
howmuchwillitsnow.com

wunderground.com (great UI, graphs temperature forecast for you and you can hover over it for instance to check out the likelihood it will be raining at 1pm on Tuesday)

wunderground.com
wunderground.com

Add Media

weather.gov (links to the national weather forecast broadcasts)

Screenshot from 2015-02-16 23:37:42

sailing.mit.edu/weather/ (comes with webcams! very clean and detailed)

sailing.mit.edu/weather
sailing.mit.edu/weather

weatherishappening.com (if you like a dose of snarky with your forecast)

weatherishappening.com SNOBLOBS
weatherishappening.com
SNOBLOBS

here is a narwhal on a narwhal

to end on a happier note, here is some cuteness for you

narwhals on narwhals
narwhals on narwhals

I finished a hexapod instructables, get featured, and then mope some more

I finished my second instructables ever! This one was a lot more “successful” than my first one — it was featured on the front page for a day or two. 😀 yay!

This is the instructables for my 18 degree of freedom (18 servo) hexapod:
www.instructables.com/id/Simple-18dof-Hexapod-Arduino-nano-optionally-wit/

It probably took slightly less time than my 7 minute video on the design process (which took at least 2 or 3 full days) yet garnered about 10x the views. The little star in the upper right hand corner stands for featured.

All that it means is that your instructables gets put on the front page for a little while. At least it did much better than CNC nyancake. Apparently nyancat is a thing of the past for everyone except me XD;

day 1
day 2

It was featured within hours of posting, crazy moderators.

instructables published jun 24th

It is gratifying to see that at least some of the thousands of people who visited that instructables clicked through to my took-ages-to-make design process of a hexapod video. See spike in traffic at the end of June.
I still don’t know the secret to getting comments though. I want to interact with people virtually! At least for now.
As usual — then I mope about how I focus too much on these sorts of stats instead of going out and “enjoying what I do” or whatever.
But yea, all in all. Four years ago I never would have imagined being on hackaday and having a featured instructables. These were all things I saw the peers I looked up to do, not myself. Yet I find myself qualifying these accomplishments — it was just for a project I basically copied off the internet, it is just for a really derpy hexapod I never really finished, etc. I have an awesome friend who was published in science as an undergraduate, yet she always qualifies her publication, and it’s obvious that she’s missing how amazing this whole thing is. Maybe I am doing that?
Lack of self-confidence is unattractive and can make other people difficult to work / high maintenance with, yet I can’t get rid of this in myself. Grr! At least there is hope for me. I can reasonable list three things every day that I am proud of myself for, unlike some friends of mine. x___x must spread positive energy

Well, that’s life in the first world. I am in an amazing spot for myself currently — working on my own startup with two very good friends who are still my friends so far, assisting with a go-kart class for pay, no financial issues for at least a few months — yet I still feel not-legit, like I haven’t really built anything really cool or robust. I’m not sure what it’ll take, since I certainly won’t catch up anytime soon to people I look up to in the areas they specialize in.

I guess that is just something I will have to get used to. Or I could finish kiwikart

hexacon. well, hexapod jewelry and then someday a post about hexacon

i wanted to make jewelry
i also need prizes for saturday’s hexacon
hexacon2013.mit.edu
hexacon2013.eventbrite.com

bought some supplies from http://www.yelp.com/biz/artist-and-craftsman-supply-cambridge, then lasercut some hexapods from a vector SVG file of my hexapod CAD files

I added some lock washers and made them asymmetrical, because I miss the ones that +Hanna Lin made for me a while back that look like this, but prettier and more functional.

lock washer source, MITERS.mit.edu
Fatal flaw of acrylic jewelry: it only wants to face one direction, sideways, by default (I twisted it around to take this picture). Ah well. A puntly-hour’s worth of work.

Hexapod conference? how to plan a conference budget?

caution: hexapods ahead. cc0

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:
https://docs.google.com/document/d/1rq3cIFy9j1FjbIYA67gpZCksZKgtXzLZrxkLw93_v2s/edit

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
An extracurricular undergraduate reading group I led last year.

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.

I made a video about hexapods.

I made a video about hexapods! yay. I’d estimate it was a full 4 or 5 days working on it, learning final cut pro along the way. It basically covers my journey through 2.007 two years ago, and is meant to be a resource for students in the class.

Note to self: shortcuts: < > ctrl-= alt-w

Meanwhile, I think an instructable a week sounds like an excellent plan for Spring semester senior year.

recap (maker faire, hackaday and hexarideablepod, emergency nyanpancake)


I guess now is as good a time as any to reflect on my years of building things (years now?!). Hello, crackaday.
Quick note: hexarideablepod is run off of two A123 magic 12v batteries and is actually controlled by drill triggers. @__@

First, a brief interlude.

Back in the day I made some nyancakes for MAS.863. That was cut out on the shopbot from pink foam, around which I poured a full pound of easymold two-part silicone mix, aka $26.52 1lb Easymold Silicone Rubber (price has gone up since then).

one of the earlier tries. turns out it’s sad without a mold release agent, aka vegetable oil.

Kind of pricey for a single cake. Most of the silicone goes into the areas around the nyancake which can’t really be hollowed out without doing a two-part mold process. Being utterly lazy, I didn’t do that.

Well, lately I’ve been thinking that a better idea is to make cute little nyancupcake molds. So Saturday around 3 am when we were packing up getting ready to leave for maker faire, I decided to emergency nyancake.

  • 3:19am

Nancy R. Ouyang
hi charles, can i 3d print a tiny nyancake right now?
like 1” x .5 ”
if not that’s okay!
i recognize i am slightly crazily procrastinative

  • 3:21am

Charles Guan
squee squee squee
0_0 do you have the stl?
it’s gonna take like 15 minutes just to heat the machine up
i somehow think this is a bad idea 0___0
if you’re really down i’ll go heat it up right now

This actually turned out pretty well!

Files: https://github.com/nouyang/orangenarwhals-nouyang-blog-files

So then I was staying over at Dane Kouttron-wrote-own-software-for-giant-robot-arm-turned-3d-printer-currently-printing-[transportation to be disclosed] person. After getting home from maker faire I took my 1 lb Easymold Silicone Putty ($20) (putty, because since this is way smaller I don’t need to pour in the silicone) and mashed the two parts (white and purple putties) together and then stuck it into the mold. The only issue is I lost one of the eyes which wouldn’t come out of the 3d print.

The next morning, I pancaked! Using box pancake batter. This turned out surprisingly well — the pancake batter resulted in lots of holes yet it held the shape pretty well. We vegetable oiled the interior, spooned a bit of batter in, used the spatula to speed flip everything over, and let it sit for a few minutes, and then took it off the burner and let it cool to medium hot (this is a theory, that letting it cool a bit = contracts and better shape retention, and cooling too much = well idk).

ahhh one-eyed cat pancakes

Then once we got to maker faire I had this awesome idea of getting someone to 3d print me a slightly larger cake mold and ask the pancake printer people to make some pancakes for me.

Some helpful people in the 3d printer pavilion printed this out, although it finished after we left so no pancakes :'( Ah well, good shot at emergency maker faire project.

Note spider webs, sphincter compared to earlier print; need more drool control 🙂 Appears to be branch from MTM snap

Okay, so back to existential crisis.

(I am totally doing this to intro all my projects so far, because I’m shameless. Also I made a portfolio recently and realized I should actually organize things).

I would count 2.007 as the first time I really started building things (which is an interesting thing in itself — does this mean I only count electromechanical things I built mostly by myself?). As usual I’m plagued by my sense of inadequacy. Because I try to point out to my friends how awesome they are when they talk about their failures and envies, I can recognize the symptoms of this cognitive distortion. And at maker faire — I got a hackaday post off of what I would call a ripoff design, when all my friends have made such awesome projects. Just at maker faire, there was Bayley and Kramnik‘s oneTesla (soon to be kickstarted), Nick’s wholly unique forging-his-own-path-at-MITERS musical instruments and tricopter, Charles’s chibikarts, Shane’s crazy motor controllers, tinykart, and quadrotor, also Ben Katz’s I’m-a-crazy-freshman (okay Kramnik is too but he’s not new to MITERS) awesome!scooter, dgonz‘s scooter and robot arm, Hunter Bank’s let-me-almost-make-an-entire-scooter-in-two-days (designed beforehand), Dane‘s crazy death scooter (pics not up yet), Ted‘s bike-scooter, and a ton of projects

oh robot hexalord all the projects

Anyway, you see what I mean? Here I’ll list out how I think about my projects. I’ll roughly list my projects in my scale of rather inadequate to completely inadequate. Mostly it’s a combination of two axis — how much engineering I put into it and whether it actually worked or not.

1) hexapod 18 servo
— failure because I never built controls / even sensors for it. Also now dead in the water because after several plane trips, I appear to have killed the pololu serial servo controller – a whopping $50 — which goes to teach me a lesson, buy things with the bare minimum I need because I’ll likely destroy it ;___; . To become legit: need to make actual (3d printed?) case for it, also figure out servo calcs instead of beast-it-and-hope-it-works as I’ve been doing. Figure out how to write inverse kinematics controls, make a GUI interface, make it dance.

2) hexaridaeblepod
— failure because I did very little engineering — almost entirely a ripoff of the epic rpalanteo instructables. Also I don’t think I’ll be working on anything other than maintenance for a long time. Well, maybe add some LED strip lights and a speaker playing nyancat, because I am apparently hexapod nyancat project person.

fewer kids than last year, also no rides the second day because I didn’t have batteries because other people’s projects ate them… ;__; the whole reason I brought hexarideablepod was to give kids rides
Also it runs much faster / scarier at 24v but I seem to be on a blowing-up-controllers spree right now.

3) Nyancake
— failure because zero engineering involved besides CADing the model.

4) persistence of vision yoyo
Failure because I never actually carried through on it and got it working (display text) with rotation, and got it to work as a yoyo. Although I did learn about charlieplexing, wrote terrible pov yoyo code which only worked when you waved the yoyo in a straight line.

5) 24v motor controller (h-bridge)
Well, I attempted to make this in 48 hours. That was a fail. I am most sad that I failed to even get to test it because I had issues with routing tiny traces under components, which the mill didn’t cut out, and also soldered the caps on top instead of poking out the bottom so I couldn’t reach the leads to solder them down. Derr. Fail. It was a simple H-bridge controller and I couldn’t even manage that despite lots of help from the thorough documentation on Charles‘s and Shane’s blog. Also it played into the pattern (yay cognitive distortion) of me not finishing final projects. -___-;;

6) Electronics vending machine
— failure because oh yea, speaking of not-finished final projects, this was for MAS.863, I made this over 48 hours — CAD’d and lasercut over 24 hrs — and I skipped the entire final class for it and only brought the half-working thing to the open house. Professor Gersheneld, I’m super sorry for taking up a spot in the class and not doing my fair share of work, although I guess in the end I am the only who lost out.

7) Random lasercutter stuff
(lab glass, business cards, clock)
— failure because, well actually I really like the lab glass present for Dan Fourie (found glass of reuse = free gift for putz cruftmas), but for the most part, no engineering involved.

gift for my friend, alice chung
clock face for what was actually supposed to be a waterjet-marble class, but I wimped out.
Cathy Wu! and anodized aluminum laser-etched..
yay fuzzy pictures. “MIT 2013, Meche (2-A), ~dream it. build it. ~ orangenarwhals.blogpsot.com”

8) Nyanweight
— failure because I intended to make a 3d nyancat, but ended up making an engraving only because I spent countless hours and couldn’t get masterworks to overlap the cuts in the right order (yay pixels = many paths ending on the same point).

speaking of which, I don’t know where i put this. oops.

9) hexapod reading group
Katy Gero took charge and spearheaded the lasercutter – bristol board – doube-sided tape replica of berkeley biomimetic millisystem’s hexapods. Cool linkage design. So again I had nothing to do with the design, although I’m happy I inspired people to make things.

credit: katy gero

10) nyantart
— failure because it is entirely a derivative of lvl1 work. Zero engineering! Yay GIMP trace of bitmap on internet!

hi lasercutter <3>

11) Metrify wireless sensors
— failure because I didn’t do any board design (all by mark spatz) — I was more business “cofounder” (no, we didn’t pursue the project as a startup, but it did help me get a job my amazing internship at fitbit). also uber thanks to startlabs for funding us and redstar ventures for hosting us.

daww generic chinese nrf24l01+ knockoff of nordic breakout board.

12) 2.008 project
— failure due to my terrible grade in that class, also I don’t feel like I contributed much to my team. I didn’t pay enough attention to lecture even though I am fascinated by manufacturing, I didn’t learn all the ins and outs of the magical mold-making process since I worked on the thermoform mold.

does it say MIT? or hell?
Hmmkay. Look, all the dumb projects I have done.

fixing the hexarideablepod shaft slipping issue

I’ve had this recurring problem where the set screws on hexarideablepod prevent the aluminum torque transmission bar from slipping radially on the shaft, but have issues preventing it from slipping axially.
Today I learned today courtesy of Mars, regarding ways to prevent axial slippage:
  • Retaining rings (clips, e-clips, c-clips, circlips) are more for axial alignment, not very load-bearing
    • E-clips are “Side-Mount External Retaining Rings” 
    • the middle part of the E isn’t supposed to go inside a keyway.
      Yea, that retaining ring I put on earlier (sticking the middle part in the keyway and dremeling an imprecise groove for the other “ear” parts of the e) wasn’t actually being that useful, although it did seem to help. 
  • Cotter pin + washer is a good solution, 
    • can probably take a hand drill even and drill a small diameter hole through the shaft
  • Even a small divot instead of a flat channel will go a long way to helping the set screws not slip around the shaft
  • I could mount a steel plate to my aluminum linkage and weld the linkage permanently to the motor shaft steel, 
And then finally the “duh” easiest solution, since I’m only concerned about inward slippage, is make a PVC standoff. 
This is super exciting, since I can finish this in 15 minutes (wellllll. If our bandsaw wasn’t out of service…. a long story… oh MITERS) and then the hexarideablepod will be mostly mechanically robust.
The electricals will be a piece of cake because I found drill triggers that are 24V 16A and make me happier than my 15V triggers. (yea, yea, I should make my own dumb motor controllers, but the packaging is just so convenient. People will even sit on turned-off hexarideablepod and play with the triggers just because). So I just need to rewire that, and make a more permanent battery mounting solution, and I’m all set.
Oh, and find another tennis ball, I lost one of my floor protectors.
Also add some 12V rgb LED strip lighting.
Next for NYC Maker Faire: 
  • hexadancingpod
    • model & print new body
    • buy new pololu serial servo controller because I am too lazy to make my own
    • build battery pack
    • buy accelerometer and ultrasound (or find)
    • write software
  • nyancat singing poptart
    • arduino + speaker
    • arduino + piezo
    • attiny + piezo -> buy surfacemount attiny’s, scrounge up piezos (get digikey account)
  • vending machine
    • add buttons
    • if time, add ir led sensors
    • ??? payment ???
  • pov poi
    • buy rgb LEDs
    • route board
    • packaging?
Other notes:

My shaft measured about 43/64” (672 mil) , so it seems like the standard given motor shaft diameters, in this case 3/4” (725 mil), is larger than the actual shaft size (? check this with someone).

========
Some notes I was taking:


Common ways of preventing axial slippage in the inward direction:
  • cotter pin
    • requires drilling a thin hole all the way through the motor shaft
  • retaining ring http://www.mcmaster.com/#retaining-rings/=jcg38v
    • requires machining a precise groove all around the motor shaft
    • which means if I lamely do it with a dremel (how do people do it anyway? build a fixture with a cutting edge, apply power to the motor, in a temporary lathe sort of way?) then the retaining ring isn’t going to be very strong (it’ll pop out).
    • I’m not sure about installing it since I have keyways on both sides of the shaft so it’s hard to not have one of the ends of the “e” dig into a keyway instead of a groove.

Summer: Rideable hexapod, check

teaser pic

Ah, where’ve I been all summer?

Having lots of fun, actually, but I’ve been hiding in my codefail cave and then I went and lost my camera.

Poof, hundreds of meticulous documentation pictures. Serves me right for not documenting as I go along / backing up my pictures.

Above is a pic of hexapod before I added the foot controls. Which are now being demoted in favor of joystick controls. But I did finish it in time for dorm rush / hall rush and gave lots of froshlings rides! And discovered some serious issues 🙂

Hexarideablepod is based off of a very detailed instructables called Hexabot. I’m slightly embarrassed by this fact, for whatever reason, and even though hexarideablepod only deserves my love (it already has my blood, sweat, and tears…)

Yea, that’s a racecar seat that my fellow MITERSians helped me recycle from an old unfinished vehicle 🙂

Strange and Beautiful Hexapods (Spider Robots), A Gallery

Hexahelicopter: ridiculousness.

 http://www.youtube.com/watch?v=4Wy0s0S8eZQ

Q: How many species of hexapods (six-legged robots) are there in the world? Oh, oh dear.
A: A mind-boggling awesomespectacular amount.

Here’s a compilation of some of the hexapod craziness out there. The sheer number of different hexapod designs out there is mind-blowing.

(p.s. for ideas of simple ways to build one, see my build post: http://www.orangenarwhals.com/?p=202)

Infinity Degrees-of-Freedom Style

To start off with, you guys have all watched the dancing hexapods, right?

http://www.youtube.com/watch?v=msaWXY3OuQQ

Chopsticks (yes, the robot frame was made of snapped-in-half bamboo chopsticks o.o)

 http://letsmakerobots.com/node/26107

[update 8 dec 2011] Cheaply, out of wood:

http://forums.trossenrobotics.com/showthread.php?4102-Low-Cost-Hexapod

Ant-like A-Pod

http://forums.trossenrobotics.com/showthread.php?t=2762

Hexapod that learns to walk using machine-learning algorithms! shiny shiny, and good music too:

http://www.youtube.com/watch?v=O3ovrT8pWww
http://hplusmagazine.com/2010/02/15/can-he-make-dancing-hexapod-robot-happy/

Tiny

http://www.custobots.com/products/pre-built-mini-hexapodinno-kc01001
http://www.youtube.com/watch?v=glNS81Kgk7g

Sexy

http://www.hexapodrobot.com/forum/viewtopic..php?f=5&t=389

Sheer Giant Awesomeness Style

Spider Tank (An entire series on Youtube!)

http://www.wired.com/magazine/2011/02/st_obsessed_robot/
The cute prototype: http://www.youtube.com/watch?v=_6qpSOjtB2E

How it works: http://www.youtube.com/watch?v=is7x_atNl94 (someone attempts to explain it here: http://www.youtube.com/watch?v=NJjX_YbqTC4)

The series: http://www.youtube.com/watch?v=86Krv3gE-c4

Walking House-style (by MITERs alum Sam Kronick!) (yes, the scale of this is where humans fit inside easily)

http://www.youtube.com/watch?v=gkb6jfEwe0g
http://www.n55.dk/MANUALS/WALKINGHOUSE/walkinghouse.html

Simple Linkage Style
General idea: Cant one side up and move legs forward.

3D printed

http://www.thingiverse.com/thing:5156

Rideable

http://www.instructables.com/id/Hexabot-Build-a-heavy-duty-six-legged-robot/

[update 8 dec 2011]
Look it’s bicycle powered

http://www.youtube.com/watch?v=jJY1fqzuqL0

Tiny (Pololu)

Simple Hexapod Walker: http://www.pololu.com/docs/0J42
Knexapod

http://robotics.hobbizine.com/knexapod.html

Even simpler lego one:
http://www.youtube.com/watch?v=MZ9QOjx-7FQ

Boebots parallax:

Lego Pneumatics-style
Mondo Spider– Hydraulic, electric

Jensen / Klann Linkage style “hexapods”

(for a comparison of the linkages: http://www.youtube.com/watch?v=WsRVu8BoSN4)

Uh… more like infinity legs. But same order of magnitude 🙂
Knex: http://robotics.hobbizine.com/knexabeast.html

http://www.youtube.com/watch?v=hz4mflE2foM

Steam Powered! Wow.

http://www.crabfu.com/steamtoys/rc_steam_spider/ The Crabfu site has many other wonders as well.

And semi-relatedly, cute mini-windbeest. D’awww…

http://crabfuartworks.blogspot.com/2011/01/gakken-otona-no-kagaku-strandbeest.html

Holy cow that’s robots on speed. This just has to be watched, no image will do it justice:
Hyper fast robot line following  http://www.youtube.com/watch?v=4XiRxNkZleY
(more closeups here: http://www.youtube.com/watch?v=-Soq9qpK5Ac)

[update 8 dec 2011]
Rideable
okay, not simple-linkage-style, but rideable! yay

http://www.orangenarwhals.com/wp-content/uploads/2011/07/uak5f.gif

http://www.youtube.com/watch?v=eE9HqGas7FM&feature=fvst

Research Hexapods

(theses are an excellent source of juicy details!)
DASH Resilient High-Speed 16-gram Hexapedal Robot 
By “resilient”, they mean “let me drop this robot off a the roof of a ten-story building and have it walk away perfectly fine”…. o___O (28 meters, actually)

http://www.youtube.com/watch?v=LsTKAtBBkfU
Thesis: http://www.eecs.berkeley.edu/~paulb/IROS09_DASH_submitted.pdf

Origami hexapod?

http://robotics.eecs.berkeley.edu/~ronf/Prototype/index.html
Climbing robot, DIGbot (awesome site!): http://biorobots.case.edu/projects/climbing/digbot/

About halfway through this vid, it climbs up a tree trunk! http://biorobots.case.edu/projects/climbing/digbot/natural_1.wmv
The thesis: http://biorobots.case.edu/projects/climbing/digbot/thesis_Diller.pdf

Another climbing robot, RiSE:
http://kodlab.seas.upenn.edu/~rise/newsite/

Pneumaticals and FAST and cute -^-^- Stanford Sprawl and iSprawl: (esp. see 0:43 mark)

http://www.youtube.com/watch?v=GC4vWKenA7Y
The website: http://www-cdr.stanford.edu/biomimetics/ (click on “Robots”: http://www-cdr.stanford.edu/biomimetics/documents/sprawl/)
Thesis: http://bdml.stanford.edu/twiki/pub/Rise/IndependentSprawl/Kim_A038_CLAWAR04.pdf

Rhex, http://en.wikipedia.org/wiki/Rhex, http://kodlab.seas.upenn.edu/RHex/Home

Stiquito,  http://en.wikipedia.org/wiki/Stiquito, http://www.era.lib.ed.ac.uk/bitstream/1842/2574/1/Rosano%20PhD%20Thesis.pdf

Random thesis with a lot of theory and less building: http://poisson.me.dal.ca/~dp_08_02/Site/Documentation_files/Build_Report.pdf

Controls Thesis nom nom: http://www.sigada.org/ada_letters/march2002/thirion.pdf

MIT Leg Lab Controls thesis: http://www.ai.mit.edu/projects/leglab/robots/robots.html

(pdf at http://www.ihmc.us/users/jpratt/publications/jpratt_masters_thesis1995.pdf)

Thesis-y youtube vid, background on hexapods:
http://www.youtube.com/watch?v=eunuHrTPS1o

Old-school 18 motor hexapod, back in the 1980s: Odex I

http://www.theoldrobots.com/odex.html
Schematic: http://www.genomicon.com/2009/09/the-functionoids-are-coming/

NASA GIANT hexapod, wheeled hybrid “ATHLETE”

http://www.youtube.com/watch?v=vwFrCpYavt4

What the…

Oh, and then you can use your robot as a platform and attach weird things to it. 😀
18 servo planter (Farmbot) — lynxmotion body

http://www.youtube.com/watch?v=ACtihXjq2B0

18 servo CNC Hexapod Router

 Video: http://www.youtube.com/watch?v=quN37YskoaM
Construction details: http://www.hexapodrobot.com/forum/viewtopic.php?f=14&t=12

Toys
ELEKIT MR-9722, aka Avoider III http://www.youtube.com/watch?v=nc-viPoI1iY

Hexbugs, which seem like toy rip-offs of research robots / the internet (Jamie, of Spider Tank / Wired fame, was a bit upset about this):

http://en.wikipedia.org/wiki/Hexbug

And that’s all for today folks. Whew.
Hope that gives some inspiration for building hexapod / spider / legged / AWESOME robots 🙂

Appendix


Sellers: (product datasheets are an excellent source of information for advice on how to build your own)

Misc. Documentation:

My main aids in this search: (I mirrored the images, because I hate seeing beautiful image collections destroyed by dead links)

I mirrored the images here:
https://picasaweb.google.com/nancy.ouyang/StrangeAndBeautifulHexapodsMirroringImagesFromTheWeb

And, in closing, lego shrimp climbing! An entirely different way of solving “how to climb over obstacles.”
Lego Technic SHRIMP http://www.youtube.com/watch?v=mW4LJW6j05E

Puaghhhh. Who knew compiling images would eat 6 hours of my life???

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edit 10/13/2010: more hexapods, don’t think they’re mobile but so pretty!

http://www.microbotic.org/singer.htm

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edit 17 dec 2011:

http://www.hizook.com/blog/2011/11/28/jambots-soft-robots-based-particle-jamming-hexapod-irobot
eeeee particle jamming hexapod! hehe. soft hexapod~~