NASA TETRIX Projects

Post-July 4: Sunday, 8/8

by on Aug.07, 2011, under Week 5

Lot of reworking the structure.  Redid the walls, the entire base replaced with wood, mounted the controllers to the wood from below, mounted the NXT, etc.

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Post-July 3: Friday, 8/5

by on Aug.05, 2011, under Week 5

Worked on remodeling the physical structure of the bot,  Changed the gear ratio of the ramp motor, changed the ramp structure, took off the metal base structure (moving to wood over the weekend), changed the code. Etc.

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Post-July 2: Tuesday/Wednesday/Thursday/, 8/ (2/3/4)

by on Aug.04, 2011, under Week 5

I was sick on Tuesday, had an allergist appointment on Wednesday, and did some website work on Thursday since I was feeling unwell from the appointment, so  minimal work.  :(

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Post-July 1: Monday, 8/1

by on Aug.01, 2011, under Week 5

Working alone, today is my first day after July.  I’m attempting to finally get the image gallery working, but mostly to work on getting the Carrier Robot ready for a 2 day workshop in August.  I plan on improving the ramp, by using both encoders and a 180 degree lifting mechanism, as well as improving on the crater detection system.

Future plans for each robot are highlighted below:

Axel Rover:

iPad Controller:

Carrier Bot:

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Day 18: Thursday, 7/28

by on Jul.28, 2011, under Week 4

Today was our second to last day and thus there wasn’t much to do.  We spent the first half of the day sorting kits: we finished three TETRIX kits and would have finished more but there are many bent or broken or missing pieces.  We finished all of the LEGO kits, however one, which was already in the Botlab when we came, has many missing pieces.  Also, we have many spare pieces, such as 8 extra motors and four extra NXTs.  At lunch we went to the CEEO barbecue, where we discovered someone had made balloons with balloons inside of them, which was pretty mind-bending.  Upon our return, we cleaned for a bit, then spent the rest of the day playing another capture-the-hidden-flag game, which stalemated as neither team could find each others flag.

Daily Thoughts:

Dean: Sorted LEGO kits, I finished a bunch of TETRIX kits.  I made a LEGO airplane but had to take it apart promptly because people needed it to sort kits.  I redesigned the iPad robot to use only one kit and fixed some of the robot’s design flaws.

Lawrence: I wasn’t here today.

Jess: Today was marked by kit sorting. We hardly did much more.

Briyana: All we are doing is rearranging the TETRIX and LEGO kits again.

Sarah: We sorted LEGO kits and played outside.

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Day 17: Wednesday, 7/27

by on Jul.27, 2011, under Week 4

Today we had our absolutely final demos.  The Axel Rover worked well except during the demo it got tangled in it’s own fishing line, a seemingly common problem now that the spool is attached externally, rather than on the rover.  The Carrier Bot’s ramp was not demonstrable as the program for lowering and raising the ramp does not dynamically adjust for the amount of power left in the battery pack, and thus the amount of power the motor is getting.  Apparently Sarah and Briyana wrote the code for lowering/raising the ramp on a battery pack with low energy, so when a new battery pack was inserted the ramp overextends and thus is unusable, as the over-extension is what caused the motor’s to start smoking in the first place.  Dean’s iPad bot worked flawlessly inside, including on the conference room table, however the fact that one motor starts before the other (rather than both simultaneously – the code says start both at the same time) was made more evident when the ground had more friction; ie. pebbles.  After that hour-long demo, we gave our demos again to the elementary school students having summer camp at the CEEO.  The iPad controller worked perfectly, the Carrier Bot had the same ramp issue, and the Axel Rover went on a grass hill way too steep for it and promptly got tangled in it’s fishing line again, promptly cutting it apart.  After the demos (and a bit before), we sorted LEGO and TETRIX kits; we have 10 and 9, respectively.  So far, 4 LEGO and 2 TETRIX kits are entirely sorted.  The final hour was spent playing an intense capture-the-hidden-flag.  The only reason team Purple (Sarah, Lawrence, Me) won was because team Pink hid their notebook (the flag), under a car; which drove away.

Daily Thoughts:

Dean: Presented to Morgan and Co.  The Thai food was good. Cleaned up the room, no longer such a mess.  CTF fun.

Jess: This day was marked mostly by mediocrity on the part of the robot. We finally tested it outside with the spiral code, and that worked pretty nicely, except for some sort of mysterious spinning in place upon completion of the code, which I could not trace back to the code I wrote at all. I suppose most of the robot actually wasn’t mediocre, in retrospect. The wire/spool apparatus and use were mediocre. Tetrix is mediocre is the point. The wire kept getting wrapped around on things, and at one point it got cut by the robot itself, making us look like we had no idea what we were talking about in front of the elementary schoolers.

Briyana: We presented our project twice, to a few CEEO workers and elementary school students. I also began reorganizing the TETRIX and LEGO kits.

Sarah: I realized in the morning that the ramp for the robot wouldn’t work because when we tested the ramp and it worked, the motor battery level was lower than it was at this moment.  This caused the motor to go much further and the door/ramp would go 180 degrees rather than 90 degrees.

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Day 16: Tuesday, 7/26

by on Jul.26, 2011, under Week 4

Tomorrow is our final demo to Morgan Hynes (my boss), Ethan Danahy, Merredith Portsmore, and Magee Giarrosso.  From 12:30-1:30 tomorrow we will be doing demonstrations of our completed product, as well as talking about our sources for inspiration, our reasons for doing what we’ve done, what we’ve done, how what we’ve done can be related to middle schoolers, what we plan to do in the future, and what we have learned during this internship.  We wrote down the answers to these questions in anticipation for tomorrow’s lecture as well as finalizing the robots.  The Carrier Robot was having door opening issues and those were worked on.  Dean’s iPad Controller, since it works very well, was left untouched, however, the iPad demo robot was reworked to include a handle for easier transport.  The Axel Rover got a cardboard shell around it (with access points for the NXT and the power switch), but, after assuming a motor was broken, the shell was removed so as to expose the wiring.  After troubleshooting, Lawrence and I eventually managed to pinpoint the cause: we had accidentally switched the spool’s NXT and the rover’s NXT, so the code we were running actually only was turning one motor on at any given time.  After that hiccup, we reattached the shell, this time with convenient flaps for easy access to the wiring.  During this time, Jess wrote a code for examining terrain; the robot travels out from a certain point, then spirals back to the starting location.  However, due to the aforementioned mistake, we had only ten minutes to test the code outside; the Axel Rover runs well on wet grass and mulch, both up and down a shallow hill.  The rover still needs to be tested on concrete, dirt, and up a steeper hill.

Also, at around noon, a prospective student, Alex, from New York came by and we gave another quick demo to him and his mother.  During Lunch, I showed him around the CEEO.  At around 4:30, after all the high school students had already left, I gave a short demo to a summer class teacher who decided she’d like to use a working version of the carrier robot for a two day activity with middle schoolers.  Therefore, I’ll spend next week finishing up and perfecting the carrier bot so we can actually use it in a true class setting.

Daily Thoughts:

Dean: Prepeared for demo on Wednesday.  Fine tuned the iPad robot controller program.

Jess: This morning I wrote a really awesome roomba-esque code for the rover. I’m rather proud of it, and it reminds me of my robotics origins working on iRobot Creates for Botball. It isn’t necessarily an independent program, since it is totally static and doesn’t change at all based on environmental stimuli, but it is significantly more sophisticated than a boring old drive straight program. This one drives to the center of a crater and then spirals back to its mothership. It is my first program utilizing sub-VIs, which allow me to simplify my main code and make it look less cluttered and make more sense at first glance. All day the robot itself has been out of comission due to electrical failure and further improvements. A protective casing had to be removed several times because the robot was being fickle. Only by the end of the day was it anywhere near successfully repaired and able to be tested, leaving no time to actually test my nice code.

Briyana: Today we reattached our ultrasonic sensor for our robot to be a crater robot again but the only difference was now it has a sometimes-working door/ramp.

Sarah: Today I worked on making a mini-robot follow a line.  It didn’t work because the mini-robot’s wheels kept getting stuck at various places on the ramp/Carrier Bot.

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Day 15: Monday, 7/25

by on Jul.25, 2011, under Week 4

Today we had our final demonstrations at the Dr. Albert F. Argenziano School in Somerville, MA.  Since we had decided on longer, hands-on activities rather than powerpoint presentations and talking, the demos of our TETRIX robots was limited.  Jess and Lawrence just talked about the changes they made to the Axel Rover (external spool, different wheels, different frame) and then spun up the motors.  Sarah and Briyana just showed off the Carrier robot and opened and closed the door.  Dean and I showed the new GUI and the new robot we had built for the iPad controller.  We then divided each class into three groups; each group was assigned to either the Axel Rover Activity, the Carrier Robot Activity, or the iPad Controller Activity.  Each class seemed for the most part interested, with the occasional disinterested student.  In the end, I think providing them with a hands on activity was far more interesting then them listening to us talk.  For future demonstrations the solution is to have a longer period of time to work with the students, rather than just an hour.  That way, we can give our powerpoint demonstrations and let them do the hands-on activities at the same time, without running our of time.  -Nicolas

Axel Rover Activity:
This activity was a simple, hands-on, creativity challenge.  Designed for 6 students, the activity had 6 bags, labeled from A->F, containing a NXT brain, a single motor, an NXT cable, necessary axles and connectors, and then a handful of random LEGO parts, but no wheels (except for one kit with small pulley wheels).  The goal was to build a robot that can go forward, backward, and climb over a set of three NXT bars screwed together, once with the bars facing up and once with the bars facing down.  The NXT had two codes on it: the “forwardbackward” code uses the left and right button to travel backward and forward until the orange enter button is pressed and the “btns” code uses the left and right button to turn left and right until the orange enter button is pressed.  The first code was for the initial activity and the second code was for an extra activity if any two groups accidentally combined their pieces or if there was extra time.  Once the students were shown the pieces, shown how to connect the motor to the NXT, shown how to access and run the code, and given the objective, they enthusiastically jumped on the activity. One of the students in the first class, Pratik, built a really cool walking robot that used the pulley wheels to pull itself along, rather than to spin on them in a traditional wheel-sense.

Carrier Robot Activity:
This activity was a build-it then use-it activity.  Divided into four sets, each group was provided a kit labeled either CA1, CA2, CA3, or CA4 and an instruction booklet for building a simple robot with an attached, downwards-facing light sensor.  Upon completing their robots, the goal became to get their robots up the ramp of the Carrier Bot, which was entirely white except for a strip of blue tape.  Using a pre-programmed line-following code, the students would attempt to get their robots up the ramp.  Every robot failed at the same point: where the robot hit the top of the ramp and the light sensor went off into the air.  This caused a dramatic light sensor value change, in this case causing the robot to verge to the left and get stuck in the gear/motor assembly.  In the future this can be fixed with either a ramp modification, such as having the ramp lift up to 180 degrees with the interior when the robot has climbed to the top of it, or a robot modification, such as adding a ultrasonic detector to read the distance to the ground and compensate for a dropoff.

iPad Controller Activity:

This activity was planned and carried out by Dean.  He set up a path, using tape and various obstacles, that the students would have to make the robot follow by using the iPad controls, as shown in the image above.  He first had them plot out their commands on paper, then allowed them to take turns controlling the robot.  For the last class, due to extra time, he also had one person face away from the robot without being able to see it, then had the other students tell the controller where to go.  The iPad did not work for first class due to connection issues, however it did for the second.  In the future, an LED indicator would be useful for showing whether the robot has received a command, is processing it, or has not received a command (green, orange, red).  Also, occasionally an image wouldn’t load, but that’s not something we can fix, as it has to do with the iPad itself.

Daily Thoughts:

Dean: Met with middle-schoolers again, set up a path that they would have to follow by using the controls that I made for the robot.  First had them plot out their commands then I allowed them to take turns controlling the robot.  The kids seemed very interested and animated about this system.  Also had one person face away from the robot without being able to see it, then had the other students tell the controller where to go.

Lawrence: Today we went back to Somerville to present to the Middle school students again. We just presented our prototypes that we made for the children. Then after that we did activities with the students. Our activity was to have the children to build a robot with 1 lego mindstorms motor. They had to build it so that it could climb over an obstacle that we made out of tetrix. A few of the children were successful so it worked out well.

Jess: Today we went back in to the middle schoolers and demo-ed our revised prototypes to them with some activities. It was entertaining watching them attempt to work through the challenges presented. This time, relative to the last time, they seemed much more engaged overall with what they were doing. They seemed to like building things and playing with them better than just listening to us talk and ask them for feedback, which was entirely predictable. Nobody likes to just have to listen to people talking about things when they could be doing things themself. Some of the kids seemed disinterested, but an overwhelming majority found the activities to be entertaining in some capacity, at least minimally. I also found out that the first class was a seventh grade class, or at least all of the kids I asked said seventh grade, while the other class was mixed grade. Then the rest of the day was relaxing and filled with basically nothing but finalization and writing up these thoughts.

Briyana: We went to the middle school and had them build their mini robots to follow the line in and out of our robot. They needed some help, some more then others, but the final outcome was not too disappointing.

Sarah: Presented to the middle school students again; they had a little trouble building the line following robots.

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Day 14: Friday, 7/22

by on Jul.22, 2011, under Week 3

Today was our last day before our final demos to the middle schoolers.  Also, Jess and Briyana weren’t here so it was even more hectic.  Dean finished all the xml code by extracting the code from a working robobook file and modifying it. Also, Sarah finally got the door to the carrier bot working, as well as taping down the white paper and green guiding tape inside the robot.  Lawrence finished the mechanized spool and I made modifications to the Axel Rover base: secured the NXT and switched to a two crane design (for stability).

Also, Happy Birthday Jess!

Daily Thoughts:

Dean: Did all the xml coding for the interface but when I tried to run the program on the robot, the Bluetooth would not connect (“Line is Busy” error).

Lawrence: Today Jess wasn’t in so I decided to completely re-design the spool controller I made and made it humungous an attached the spool an the battery pack an everything to it so that it would work. It ended up being very successful. It was able to pick up the robot itself that was connected to the fishing line. Nick helped me get a program for the controller which worked as well. Also today Nick helped me re-design the robot itself which turned out being better than the last prototype that we had built.

Jess: I was not in on this day.

Briyana: Was not here.

Sarah: Finally got the door working!!!

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Day 13: Thursday, 7/21

by on Jul.21, 2011, under Week 3

More building and coding [and smoking {motors}] today.  Dean made all the icons for the iPad interface; each icon was an image made in Gimp that looked like a button and had corresponding text written on it (like 6″ or 45°).  Then, in order to calibrate the robot so the degree turns were accurate, we used a compass app on my iphone, for which Dean built an ingenious mount for.  Also, Dean did all the VI coding; forgot to add a bluetooth subvi to every .vi he wrote so he had to re-add that to each of his .vis at the end, of which there are a lot.  The Axel Rover also went from being able to move it’s arm to self-right itself to having a stationary arm.  Also, the spool went from being mounted on the Axel Rover to being mounted externally on a handheld controller, since there was no more on the Rover for it.  Briyana and Sarah finished up their line following code for the middle schooler’s activity.  Also, they managed to destroy two DC motors; they accidentally left the motors continuously spinning so when the door was closed the motors would keep trying to spin but were held in place and couldn’t; the motors started pouring out smoke; and are now broken.

Daily Thoughts:

Dean: Made the icons for the iPad interface. Built an iPhone holder on the robot to use its compass to calibrate the turns.  Tedious work, paid off though.  Did all the vi coding.

Lawrence: Today I made the double powered servo pivot an attached it to me and Jess’s rover. Once we attached it we made a program and tried to run it and we couldn’t get it to work so we decided to take the servos off and have a stationary crane. Also I started to make the controller where I attach the spool to and have it run to give the robot slack and to reel it in but I didn’t finish it and it didn’t work so well.

Jess: The wiring seemed less hideous and awful this morning when I looked at it. Yet, out servo problems persisted, despite trying everything we could think of. We got some a new servo controller, hoping that would work, but it didn’t. We got a new battery, and we replaced one of the servos, hoping that perhaps low power or offset servos were causing our problem. That only left two perfectly aligned servos connected to newly redone, flawless wiring that still wouldn’t work. At times they fidget within the upper range or lower range, but the arm is unable to swing completely up and down. I noticed that some of the arm’s fasteners are scraping against the inner servo, but I don’t think that is totally the problem, since I tested it with no scraping/resisitance. In the end, servos needed to be entirely scrapped, with only one more full work day left, on which I would not be present. DC motors, for which hubs are very hard to find, would have to replace the servos. Also, today was the last day of my week before my birthday, so there was cake and everybody sang Happy Birthday. That was fun. Being a July-born person, I was never one of those kids who had cupcakes on their birthday in elementary school or anything.

Briyana: Today we went through two, not one but two, DC motors trying to get the door/ramp to move. We worked on this pretty much the whole day. I also worked on planning out the sensors for the middle school students to follow along a dark line so I placed some white paper with different color electrical tape.

Sarah: First, one of the didn’t work, then two motors burned out because they wanted to keep moving but were being held in place.  It was quite frustrating.

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