mechaFeet : Prototyping with Algodoo

I had to wait this week for the sensors I ordered to come in the mail before I continued progress on Jelly. With Jelly on hold, I couldn’t save myself from starting on yet another project idea I’ve had fermenting in my mind for a while now. It involves building a pair of mechanical chicken (or raptor) legs that can stride in sync with one another; both legs driven by the same moving part. The thing that initially inspired me to make a mechaChicken was this quirky and utterly gorgeous mechanical hand ostrich thing by Tim Lewis called “Pony” (that and all the stupid bipedal robotic dinosaurs that are in the stores for Christmas this season).

My problem is that I don’t have a whole lot of experience with big kid mechanical motion, so it took a lot of meditating on before I even got started.

Two nights ago, I laid in bed and mused over parallelograms. When I woke up, my mind was running an animation loop that I must have seen somewhere at some point in my life. In any case I understood what sort of shape I needed to build to get the movement I wanted. So, I rushed to the closest scrap of paper and drew it before the idea escaped:

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After I made the doodle I played geometry Sudoku with the lengths of the pieces. Once I was satisfied with my own logic, I designed the segments in CAD and printed the eight individual bits to test. I eagerly screwed them together to find that the ‘mechanical leg’ moved EXACTLY like I thought it should… the proportions needed to be tweaked a bit, but it worked:

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This wasn’t good enough in itself though. Now I had to figure out how to drive the leg in order to execute the motion correctly (which isn’t as easy as you’d think). After spiral-graphing the top of the ‘thigh’ in motion by manipulating the ‘foot’ of the piece, I saw that the thigh tendons were arching in circles, so I knew I needed to create a wheel of some sort… which I did, but it sucked:

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Sucky wheel sucked because I didn’t take into account that the tendon piece of the leg would need to clear past the center of the hub, flush with the wheel itself. Of course, I had a screw mounting the wheel in place, so the head of that said screw got in the way… ruining my night. Easily remedied… but… Bleeeeeeeh very fussing. so much tedious.

Around now, Mark suggested that there ought to be some sort of 2D motion simulation software out there in the ether that I could use to test my ideas. I was starting to wonder that too… as I was minutes away from hopping on Little Big Planet to make use of their physics tools, tehe.

Last night, after some hunting, I found Algodoo. What a wonderful discovery… It allows you to draw out (literally) your arms, connect the joints with screws and drive them with motors, just like life but without the toil of actually building the prototype. What do I mean? I made this in about 5 minutes and it gave me the exact same feedback:

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In my video I give a brief introduction to the software while explaining how to make my chicken leg. As of right now, I still haven’t figured out what kind of motion will properly drive it, but I’m well on my way to getting there (without wasting PLA!)

jellyBot : Rolley (the second prototype)

Ok, so the proof of concept I worked on back in October looked awesome, but it couldn’t really move on its own… and there were a couple of reasons why:

  • I had mounted standard servos on the drive shaft instead of the continuous rotation type. I found out you need more than a breadth of 180 degrees to make a rack and pinion move far enough to do anything useful!
  • Also, my drive shaft needed some roller bearings to tension the rack down onto the pinion in order to stop all the slippage.

Since both of these things involve the mount of the motors specifically, I took the time to completely redesign that whole part to be more solid in general… after all, it is the very core of the robot- therefore the most important part! Tighter tolerances = happy jelly.

So what I ended up making was a set of brackets that both servo motors mount to… the roller bearing tensioner is a separate piece that screws into both, bridging the two and making it one solid piece:

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The extra gear bit (that kinda looks like a spur in the picture above) was added to help keep the rack in alignment, but it ended up causing more problems than solving them… so I removed it. The final working rendition had a roller bearing slightly above and below the pinion itself… instead of one directly on top of it:

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After these changes were made I hooked one of the new motors up to an arduino to test whether or not the thing moved… which it didn’t. =[ BUT- it wasn’t because of the improvements I had just made. I now had a new problem to solve.

SO- the bit that is actually supposed to be moving is a sort of vertebrae or disk that slides up and down on the metal rails which the stationary servos are mounted to. One of these disks is attached to the end of each rack, but only on one side. As this goes…. when the rack moves, it tips the disk slightly at an angle… which causes it to bind on the rail rather than slide up and down it at an ideal 90 degree angle. Eh.

The solution apparently was to add some linear bearings… which I didn’t have on hand- so I faked it and just added some cylindrical tubes to the part in CAD and reprinted them. This actually worked extremely well. Not as well as linear bearings, but it did get the thing working at last:

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Accept… a third problem appeared at this point. Now that the properly tensioned rack and pinion was actuating the properly guided disks up and down the rails… there was really no quick way to calibrate the motors back to center every time I unplugged the power. Eh. Since these are continuous rotation motors, there is no center… so I had to manually pluck the pinion off and guide the rack back down by hand…

Which sucked. So… it was time to graduate from my uber basic sweep code to something with feedback. I wired up four buttons on my breadboard and Mark helped me write some code in Arduino so that each of the two servos had a switch for up and down. Now I have absolute control over the range of the motors!

So, the new drive shaft more or less works mechanically, which is swell. The next phase of development will include adding limit switches and a way for the jelly to zero itself out when it needs to… as well as some motor choreography so it actually jellies like a jelly is supposed to.

Robot Army : Final Stretch

There was an old woman who lived in a shoe… who had so many deltas she didn’t know what to do. So she put them in boxes and shipped them away, to twelve different countries so they could revolt and take over the world one day… hehe.

We’ve shipped about 150 kits at this point. The poor printer has been running at a minimum of ten hours ever single day for the past six months and I’m starting to feel like I should buy it a drink or something.

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I estimate we should be sending the last troops out to their perspective families within the next 2-3 weeks. That means this whole Kickstarter process from the brainstorming of the campaign all the way to the end has taken one whole year: November to November ( ! ).

The eBook : The final thing I need to do once all is said and done, is document my story. I’ll get to noodle up tight with my plush delta, Stitchie, and regurgitate all that we’ve gathered from this growing experience in hind sight. I have a lot to say about it, and hopefully others out there in the hardware world will find my advice useful… or whimsical.

The Coastal Campaign : So, once Mark and I finally start building the army, we need to come up with a way to travel with all 100 or so of them like one big happy family. Our plans for the winter may involve a road trip up the coast to all the cities which have hackerspaces so we can introduce the little ones to the world.

What’s Next? We will continue to sell the Starter Kit on our site as well as others potentially, although a post-KS price change is to be expected.

On a few occasions Mark and I have stolen away and worked on our next project amidst all this shipping. We have a lot of ideas swimming around, but there is still a lot to get done to the tune of building out that army first… right? What do 1000 servos sound like?? We’ll soon know!

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Here are some fun facts :

For the Kickstarter we have printed…

1400+ yellow arms

700+ paddles

300 end effectors

and 1500 brackets

we’ve burned through 25ish rolls of filament from six different suppliers (depleting the neon yellow stock of a few)

I have soldered around…

6900+ male pin headers (Mark has soldered more)

and placed around 1200 SMT parts

We’ve used 3 industrial-sized rolls of quarter-inch bubble-wrap for packing

and have shipped kits to 16 different countries!

The place where the most robots are going to is… the bay area. Take good care of our kids, Silicon Valley.

jellyBot : Racky All in one Piece

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This weekend I started printing the newly redesigned pieces for my jellyfish robot. I got about 90% finished by Sunday, but not enough was intact to start testing out whether or not the design will move like it should.

Yesterday, I scraped together the short end pieces leftover from old roles of filament to finish printing the rest of the tiny arms for Racky. Now that I’ve added a slight curve to the length in addition to the U joint at one end, it was a pain deciding how to print the piece without ended up with a pile of pelvic fur. I had to position it rocketing off the build plate with some support material, which had a 50% success rate, (which sucked as I was nearly out of yellow). In spite of the failed attempts, I got them all done… just in the knick of filament :

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Once these small arms were added to the body, I needed to come up with a better way to attach the tendrils than with twist ties (like in my old prototype). So, I made a little U joint piece that could screw onto the under side of each arm :

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At this point I realized that the jelly as a whole needed to be disassembled so that I could secure the motors onto the steel rods somehow. I had the idea to use some of the square rubber grommets that came with the servo motors to slide onto the rod, filling the small gap between the two and wedging them in place :

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Once done, I was able to put the rest of the jellyfish back together around this piece. The last bits to screw together where the tendrils to the short curvy arms I had just attached to the body :

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Everything looks nice and I’m sorta confident it will work to some degree… but before I can hook the motors up and do any sort of testing, I need to design that tensioner for the rack and pinion. Otherwise nothing is going anywhere. Alas, I’ll get to it!

 

My New jellyBot Prototype, Racky

 

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About a year ago I started building a robotic jellyfish inspired by Festo’s submergible AquaJelly. I was just beginning to figure out how to get the thing moving when I got sidetracked with the prospect of launching a Kickstarter campaign and dropped the project cold. During this whole long year while I’ve been fulfilling the said Kickstarter, this poor jelly prototype (“Boney”) has watched silently from a distant shelf in the workroom, begging me to pick it up again. Finally this weekend I was able to spend some time giving the old parts a makeover… in yellow.

I added a nice gentle curve to the moving pieces, taking after the design of its cousins, the delta robots :

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Last year I decided to use a rack and pinion to get the parts to move in leu of Festo’s fancy linear actuator that they showcase in their model. Never having used, let alone designed a working rack and pinion before, this took some fussing about to get just right. The two servo motors I chose to drive the jelly’s motion are attached to a fixed central core of steel rods which two separate radial disks glide up down upon. All of the jelly’s flowing arms will be attached to the elbow of the mechanical arms, and as the disks these arms are attached to move back and forth, towards and away from each other, a sort of circular pumping motion is made.

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The two rack and pinion sets are in place now, each on opposite sides from one another moving different pieces in opposite directions. The rack passes through a slot in the opposing central disk, allowing it a deeper breadth of motion as well as keeping it in place. The only thing I seem to be missing at this point is a tensioner to press the rack against the gear on the driveshaft of the motor, so I have plans to whip one up later tonight.

On my old prototype, I used plain long strips of sheet ABS as stand ins for the jelly’s long flowing arms. They worked more or less, but weren’t very nice to look at :

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For this rendition of the bot, Mark offered me some of his old shelf liners from the garage to use. These happened to be an awesome semitransparent gray that matches the printed parts of the jelly perfectly! I decided on an elongated spade shape for the tendrils this time :

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These pieces connect at one end to a small ring, creating the umbrella of the jelly (the delta robots watch from the side in aw…) :

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The center of the umbrella mounts to the top portion of the drive shaft with a fancy pants shape sandwiching it in place like so :

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Once I design my tensioner for the rack and pinion and finish printing and attaching the rest of the jelly’s small arms (all of this depending on whether or not my printer stops being a butt) I can then start working on some test code to get the thing moving! I have no idea really if my design will work at all… I’ll just have to wait and see. For now though, it’s getting acquainted with all of its brothers and sisters in the war room. =]

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My next post will likely be about whether or not I succeeded mechanically in getting the jelly to do what its supposed to. Cheers!

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Robot Army : Shipping at Last

Much to my dismay… I woke up last week to find that it was September. While I struggle to remember where the summer went, I think I’ll make myself a cup of chai and recap whats been going on in the past month or so.

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The most exciting thing to take place was our dry run at SYN Shop. We invited a small number of people who preordered kits back in February to be the first to pick up their newly adopted robots in exchange for testing out our instructions. Everything went smoothy, however I’m still sitting here editing the instructions… and I’m tired of looking at them. ::shakes fist:: As much as I thought I had boiled down the steps… I need to expand several of them out even more to make absolute sure that people can’t skip or misread them.

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It’s taxing >.< I definitely need to do a little research next time before I dive into producing a visual guide to see if there is a recommended method for capturing images at consistent perspective views. I ended up having a massive CAD document where all of the steps are positioned with a zillion copies of all the molded parts… which works, but there is so much now that it’s confusing and difficult to sort through.

The last thing to finish off before we began boxing things was the software (of course). We figure a large percentage of the people who bought our kit will never bother to update or reflash the code on the brain, so we want to make sure it’s exceptional. For the entertainment of those who will only ever run their delta in auto mode, each DIP switch setting will contain a different emotion… happy, sad, caffeinated, and kill (yes, “kill” is an emotion if you’re a robot). Programming a delta robot to emote is a huge challenge though, especially when you only have three degrees of motion to work with. Mark and I have been mulling over the code with “Testie” or faithful test delta, for a few hours every day trying to figure out the nuance of each; a matter of tailoring subtlety.

We finalized the code on Saturday… and by the end of yesterday had the first 50 boards burnt, bagged, and added to the boxes with all the other things.

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So yeah… the master bedroom has been turned into our mailroom (it is under renovation anyhow). All of the individual assets come together here and are getting sealed up with shipping tape at last!!!

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After we push out the first 50 kits, it’s a matter of rinsing and repeating the boxing processes four more times…! Not too bad!

The one thing that might slow us down a little (because there is always something) is that Mark has been called to work every day this week due to some major changes taking place in areas where he’s needed. This leaves me alone finishing off the last of it all : shipping labels, bubble wrapping, and giving the website a good makeover.

I can’t possibly express in writing how excited I am to finally be sending the kids out into the world. I’ve been suffering from this weird form of anxiety lately… which stems from having all this creative energy, but forcing myself not to focus it on anything because of all the work we’ve needed to do… it’s like constipation. I am really glad that we did the Kickstarter, but man will it be nice to have my free time back to develop other projects.

Lesson learned : Kickstarter is a great way to gain exposure and raise money to bring an idea into the world… BUT, however long you believe its going to take to reach fulfillment (even if you really REALLY plan) expect for it to take twice as long. The last 10% turns out being the last 90% of it all… you just don’t know it yet. Things that you write off in your mind as a non-issue expand out into several bullet points worth of extra things to manage or take care of. Don’t think for a moment that “All we have to do is…” or “It won’t take that long to…” – Those things require attention and energy too. It’s all a gigantic sacrifice, as fulfillment will prevent you from perusing other ventures. As a creative person with a mind going a zillion miles an hour – you will spin out… like me! ::spins::

That is my wisdom to pass on. Again, SO glad I have done it – but SO happy for it to be nearly over.

DefCon 22

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Picture taken by Aakin!

Sunday evening I collapsed on the couch with a nice big glass of red wine after having unloaded the very last of our stuff back into the house… thankful that I’m alive, in one piece, and that nothing critical went wrong this weekend. I have more awesome memories for the grey squishy hard drive. Here are the highlights on a few of my experiences :

Our Kids’ Second Big Recital >.<

DELTAS! They were there! This being our second time attending the con, we wanted to participate by bringing our own taste to the medicine. Friday night during the event of random fun and mischief, we had a nice dark sliver of space to set up all of our babies in. The best part being that we didn’t have any rules or restrictions for the space we were showing in like at Maker Faire. We could pretty much do anything we wanted; our own cooler filled with beer was present, our own speakers with music were set up, and we turned the back wall into a looming place of worship for those of us who accept robots into our hearts as personal overlords and saviors. <3

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However, setup left a bad taste in my mouth. We had issues during load-in involving some things we were led to believe would be provided in the room yet weren’t. This in itself wasn’t the problem; the resistance we encountered while trying to fix it was.  A few of the Goons seemed to get off on our dilemma, being purposely withholding instead of doing what they could to help, and then became pissy and annoyed with us once we resorted to taking matters in our own hands to get what we needed. If the people running Defcon expect others to go out of their way to set up art and events at their convention with nothing to show for the effort, the very least they can be is accommodating and maybe a little gracious. The Defcon staff we encountered were all stressed out and moody which might have been due to the lack of organization, or it could stand that in an economy where everyone is being paid with perceived status rather than money, undies will get knotted up… and egos will inflate. =/

Anyhow, once we were ready to go- dismay aside, everything went fucking awesome. We received an excellent response and got great feedback from fellow hardware hackers. It was the most rewarding experience to see people interact and dance around with the robots while radiating that megalomaniacal hype we’re aiming to bring out of people. I had many interesting, insightful conversations with other techie avant-garde, as well as with those of the goons who weren’t ten feet up their own asses. =]

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At the end of the night Mark and I got to deconstruct our little ones alone in private. The hallways were silent, dark, and devoid of life, which was surreal in contrast to how congested they were at every other time. In our own zen we packed up the show, unloading at Mark’s place by 4:30 Saturday morning. I slept so hard I forgot where I was when I woke the next day back at the hotel.

Darknet was a huge success!

photo taken by hackerphotos.com

Photo taken by hackerphotos.com

Everyone was working until the final hour (minute) on every facet of this event to make sure it was loaded with kickass once Defcon began on Thursday. Of course, Smitty’s highly involved live RPG was all the rage this year. Holly shit. By the time I got down to the HHV in the morning, the DarkNet badge kits were sold out! I heard that on Saturday there were 600+ people in line to fight over the remaining 80!

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The few they had left were auctioned off before Crash and Compile for over a hundred dollars a piece! I am SO PROUD of the whole team for the amount of effort they poured into coordinating things this year. It was no easy task, so I’m glad that the Defcon lords recognized this by making Darknet a black badge event this year!

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We raised over four-thousand dollars for the EFF… and for me, the great part is knowing that we did it in style ;) Darknet shirts happen to be sexy. Just saying. Virtual high-five team!

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Fellow Makers Rock Defcon with their Laser Robots!

Mark and I met two really cool people at Maker Faire this year, Kathryn and Alvaro. This tech savvy duo of robot wielding awesomeness had a laser shooting gallery in San Mateo. Being their area of expertise, they brought an amped up laser turret with them this year to compete in the DefCon Bots challenge. The goal was basically to create a robot that could scan and find blue balls (teehee!!) moving through a depth of dark space and then aim a laser to shoot at them. That’s no easy task! We came to cheer them on this Saturday and were happy to catch their big win! They were up late making last-minute improvements on their laser baby, but it paid off in the end… =] Great work guys!!!

The best badge is the one you make yourself.

In a pop-up culture of status dictated by the thing hanging around your neck, there is much talk of badges at Defcon. Black badges, human badges, modding, decoding, hacking, and alas… making your own, which a few people did. As for us, Mark and I created a board out of the key I designed for the Darknet propaganda. It’s a nice little memento for this year which we proudly bared as board designers. Purple FTW!

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We met someone who made an “Impostor” badge through OSH Park, which was the most snarky and creative rendition of the Defcon 22 badge at the entire con as far as I’m concerned :

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All of the text negated everything on the original, for example saying “light arc” instead of “dark tangent” on the back, and “found” instead of “1o57″. Tehe. In love. The UV SMT LEDs were a nice touch too.

Then there is sharpie and gaff tape :

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Because the better things in life are neon yellow.

Crash and Compile

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Glitter. What? Nah… it wasn’t me. =]

So I didn’t wear a big penis this year. To change it up a little, my strategy was to annoy and systematically emasculate all of the competitors with dolls. I built a “Barbie bandolier” which held my many personas through which I communicated during the event. This got easier to do the more hopping drunk I became. – I was sure to make a doll-sized strap on as a throwback :

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Though I spent a lot of time trying to derail team Frink, the defending champions, I poured twice as much effort into bothering the team who won this year… Sprechen Sie Dick Picks. No one could get these dudes to make eye contact with them. They had the purpose of a bullet train and though they did a good job of kicking everyone’s ass, I think they missed one other very important aspect of the whole event : by the end it should feel like a circus on stage… and everyone seemed more sober than I remember last year (but that might just be because I was more drunk than the rest). Congrats to all of you for competing! (and for putting up with our shenanigans)

Jeff and his crew did a fantastic job of preparing for the event again (Jeff is a rock star, as he also designed the board in the Darknet kit again this year in addition to preparing for the contest). Between the contest holders and the teams programming, we polished off three kegs of beer over four hours. It all went by so very fast. Here is the sexy trophy he made this year, a shiny head-sized D12 :

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SYN Shop Teaches Soldering to the World

I’m happy to say that our local Hackerspace, SYN Shop, had a presence in the hardware hacking village this year! Brain along with several other volunteers manned the tables of tight and person soldering stations, happy to show those who had picked up a kit in the vendor area how to melt lead like a pro.

When Everything is Said and Done

The child-like wonder of falling down the rabbit hole was gone, but I felt like I found my own niche in the big picture this year. I’m proud of all my friends and the work they put forth to make the event what it was. =] Time to get back to work. We’ve got robots to ship and the rest of the world to take over.

This is another notch in our belt… or shiny thing on our wall. It’s all about enjoying the journey!

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