NASA TETRIX Projects

Week 3

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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Day 12: Wednesday, 7/20

by on Jul.20, 2011, under Week 3

More construction today.  Dean spent the day learning how to setup and use the dc motor encoders so that he could get two motors to travel at constant speed, rather than power, allowing a robot to drive forward in a straight line.  In the end, he succeeded, getting a test robot I built to travel 20 feet down the hall whilst only drifting to the side an inch or two.  The Axel Rover base was fully finished, but there will probably still be future modifications.  Lawrence went to the machine shop and with Jim’s guidance custom machined a piece to mount the fishing spool to a motor.  Sarah and Briyana built a door for their robot that would (theoretically) be opened and closed by two synched servos.  In the end however those servos were too weak to properly open the door, so an encoder-equipped motor was used instead.  Also, I constructed kits for the middle school students; both an activity for the Axel Rover and for the Carrier bot.  For the Axel Rover, I made six kits (A -> F) that each had a motor and NXT, who’s goal would be to drive forward, backward, and travel over objects.  However, the pieces I provided in each kit did not include wheels, so the students would need to make a walking/crawling robot.  The code for it is a simple move forward/backward when the right/left NXT button is pressed, until the middle NXT button is pressed.  For the Carrier bot activity, I started set up four kits with instruction manual and the pieces to build a simple light-sensor controlled robot. -Nicolas

Daily Thoughts:

Dean: Started building the robot for iPad control.  Learned how to use encoders/program using encoders for dc motors.  Frustrating at times.

Lawrence: Today we continued reconstructing our NASA Axel Rover. We have the rover completely built that we know of. Our program for running the rover is not working for some reason and also the servo program isn’t working. We believe it is our wiring but we are not sure so we are going to check it tomorrow because we are out of time. Also me and Nick organized kits for the middle school kids for our presentation coming up. The kits are so that the kids can make smaller and easier robots out of Lego Mindstorms.

Jess: On this morning it seemed somewhat crazy that we had to have completely finished demos for the next Monday. Then I realized that the robot was basically done and I had a six hour period in which to work solely on the robot. Indeed, it turned out that the robot came along rather successfully. It even had a part custom made for it. We solved a lot of problems as far as actual physical construction. When it came to programming, that undid basically everything (in some cases, literally). We couldn’t figure out how to sync the servos, so I undid the zip ties that held all of the electrical parts together, undid all of the connections, and still solved none of the problems, but did succeed in losing my perfect, original configuration.

Briyana: Constructing a door and motorizing it to be a ramp (similar to draw bridge) for the mini robots to deploy from. Servo motor ended up not being strong enough so we switched to DC motors and used encoders instead.

Sarah: We are working on the door for our robot.

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Day 11: Tuesday, 7/19

by on Jul.19, 2011, under Week 3

Today was the second day of redesigning and rebuilding.  The base of the Axel Rover got a few redesigns as the holes are difficult to line up with Tetrix due to the awkwardness of the provided motor mounts. In the end, two different designs were constructed in order to evaluate which is better.  The Carrier bot started coming together, with the walls being made of cardboard, since it is an easily acquired material and inexpensive.  Originally I was thinking about their robot being made of 1/16″ Lexan (polycarbonate sheeting), however that would defy the purpose of other people being able to easily build this robot.

Daily Thoughts:

Lawrence: Today we still did more reconstructing. We came up with 2 possible ideas for our rover. Both of them are built and we will test them tomorrow to see which of the 2 are better. Also today I made a program to work the double powered servo that I constructed earlier. I made it a double servo so that it would be more powerful. I also synchronized the double powered servo so that it would be better but we ran into technical difficulties that I fixed but it destroyed the synchronizing I did. So my goal for tomorrow is to synchronize the double powered servo so that it works.

Jess: First thing in the morning I had to take apart the base I had spent the entirety of the previous afternoon building. It was growing increasingly unfeasible. The rest of the day was spent constructing two new alternatives to the base, which at times was extremely frustrating, since the holes continue to not match up in ways that have been acceptable to me. In the end, I got the servos/arm mounted in the center of one of the bases as I wished, but continued to be skeptical.

Briyana: My partner and I continued to expand and improve and have got a full base in which the smaller robots (which will be built by the middle school students) will wait to be deployed.

Sarah: We continued building the new robot. We used cardboard for the walls because it is still a prototype and cardboard was easier that using a different material.

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Day 10: Monday, 7/18

by on Jul.18, 2011, under Week 3

Today was day 1 of rebuilding and modifying our prototypes based on information gleaned from testing and demoing them.  Dean took apart his Tank robot so that the other groups would have more pieces for their own projects, since he used almost every single flat plate and most of the long bars, as well as a ton of screws and nuts.  I used this opportunity to take a SAM animation of him taking it apart, taking a picture every 2 seconds.  We ended up with 2545 pictures for a total of 5090 seconds, or 84.8 minutes.  We decided to run the resulting video at maximum fps, (30.3), resulting in the below video.

Dean taking apart Tank

Also, the two other groups spent today taking apart their prototypes and redesigning them.  The Axel Rover’s base was taken apart and new designs were thought up.  The Carrier bot’s prototype, which was at this point just a simple robot with an arm holding an ultrasonic sensor for finding craters/table edges, was taken apart and an entirely new robot was started.  Using four of the longest Tetrix beams and all the flat pieces Dean took off his tank, the base of the Carrier bot was built.

Daily Thoughts:

Lawrence: Today we took apart our old rover and completely reconstructed it. We did this all day and still didn’t finish it so it got frustrating. We tried many ways to make our rover and we still haven’t solved it.

Jess: After a rather relaxing day on Friday, and then the weekend, we had to buckle down to actual work. We started to take apart our prototype rover, as I wanted to see if I could create a better model by redesigning the base and such. I got it deconstructed within the day, and started brainstorming new ideas. Construction also began on a new base, which was rather frustrating.

Briyana: My partner and I took apart our old robot to expand and improve and have got a new base where the smaller robots (which will be built by the middle school students) will wait to be deployed.

Sarah: We took apart the old robot and built the base of the new robot.

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