The Dead Sea

It’s known as the Dead Sea because there isn’t any macroscopic aquatic life in the lake due to the high levels of salt in the water. The high levels of salt make it super easy to float in the water – it’s literally impossible to sink. It was kind of tough to hang out in the water though – February is not a good time of year for lounging in the water.

The Dead Sea is located between Israel, Jordan and the West Bank. Theoretically, one could swim from one side to the other without worrying about drowning, but it is a lengthy 15km swim. Not something I’d try, and besides, there’s probably patrols that would stop people from doing that.

The mud here supposedly has health benefits because it has an abundance of certain minerals. We saw people spread the mud all over themselves to reap the benefits of the mud. I tried a little bit on my hands and arms, but the mud just dried out my skin a lot – yeah not doing that again…

Tel Aviv

From the Dead Sea our tour took us to Tel Aviv. What took me by surprise was how much of a beach city it was!

We spent our day in Tel Aviv on the “Shabbat”, the Jewish day of rest, so a lot of places were closed. But we did find some nice meals though!

This is shakshouka, dish of eggs poached in tomato sauce, olive oil and spices. It tastes really similar to tomato sauce, but the poached egg makes everything so much better!

This is a beef tagine, a dish originating from North Africa, but it’s also common in Israel. The name tagine is cooked using a special pot of the same name. Tagines come in many varieties, but they are often savoury stews served with couscous and other vegetables.

And of course, there’s hummus! It’s savoury dish made from cooked, mashed chickpeas blended with other aromatics. The place we went to advertised itself as “the second best hummus in Tel Aviv”. So… what’s the first best hummus in Tel Aviv? I still don’t know the answer, but maybe it’s the one that’s homemade in a local’s home? This is literally the best hummus I’ve ever had, and I’ll compare all the hummus I eat in the future to this one.

That’s pretty much it for Tel Aviv and the Dead Sea – and our two-week trip! We headed to the airport three hours early (Ben Gurion Airport is notorious for having really strict security). There were multiple checkpoints and at one point, a member of the airport security staff asked us to follow him and as we walked he asked us some questions and let us go. The staff checked every nook and cranny of our bags and all of the electronics we had on us before letting us go. From there, we began our journey home.

Photos: Tel Aviv, and the Dead Sea

This year’s competition problem involved the following scenario: normally solar panels are able to rotate toward the sun, but sometimes they get stuck, therefore it requires people to go out there and rotate them manually.  Also, undersea transmission lines sometimes get severed and also require manual repairs.  Our task was to build an autonomous vehicle using a VeX Robotics Kit in about 5 hours to use in a small scale arena emulating similar conditions.  A wooden pole represented the solar panel, that we had to rotate and a plastic pipe represented the transmission line.  To “repair” the transmission line, we had to build a repair module using newspaper and popsicle sticks that could physically cover up the pipe.  Additionally, in order to reach the transmission line, the vehicle would have to cross a rice field (represented by uncooked rice) and cross a river (ensuring that no electronics get damaged, they had to be above the “water line” at all times – represented by the dip in the arena).  After designing our vehicle, we would also have to present our design to the judges.

When I heard what the problem was, I thought to myself, “this is an impossible problem given the time we have to build it ands lots of teams aren’t going to be able to perform the task”.  I guess it was supposed to be like that.  The problem couldn’t be too easy or otherwise everyone would be able to do it.  Despite the difficult task, we approached it with a super chill attitude throughout the entire competition.

As a group, we planned out what we wanted to do.  We thought that it would be straightforward to go across the river, but it turned out that it wasn’t that straightforward.  We had trouble keeping our electronics above the “water”.  The line follower kit we used could follow the black line quite accurately, but it had to be about an inch above the ground.

To make matters worse, the wheels kept falling out.  Normally, one should just have to insert the shaft into the motor clutch and connect the clutch to the motor, but the connection was quite loose. 

One of our teammates spent about 3 and a half hours trying to fix the wheels and he succeeded. It took up a lot of time that we needed for the other design tasks, but we couldn’t leave that alone since movement along the ground was a critical function.

In the meantime, we brainstormed how we would rotate the vehicle to face different directions when needed, how we would pick up the repair module, and how we would rotate the solar panel, and how to protect the line followers while crossing the river.    We also had to think of what we were going to say for the presentation.

We couldn’t really get the rotation to be accurate without using an encoder (which would increase our product cost), so we tried to see what we could do without being able to rotate the vehicle.  We could drive straight toward the solar panel, rotate it, and return to the base.  If we focused on just this task, we didn’t have to figure out how to figure out the other tasks.  We figured that most teams wouldn’t be able to perform that task anyway.  With that in mind we modified our design drastically and came up with something that kind of worked.

The end reached high enough such that we could just bump into the top of the solar panel and rotate it and then go back to the base.  We didn’t need to worry about the other task of repairing the underwater transmission line.  There wasn’t enough time for that.

When it came to the presentation, we talked about our design and answered the questions quite well, but one of the competitors asked us a question that a lot of people seemed to feel was a very jerk question to ask.  He asked “how would the client feel that we delivered a product that could not meet all the stated requirements?”  I guess he was bitter that my team beat his team last year and felt threatened by me this time around.  We answered the question by saying that it’s better to do one task well, than to fail at both. 

In the competition, a lot of teams did in fact fail the tasks and did absolutely nothing.  When it came time for our device to compete, we did what we could.  It did reach the solar panel and rotate it a bit, but not enough to rotate it all the way.   It couldn’t even complete one task, although we had tested it before and saw that it did work.

The winning team (the same team as the guy who asked us that terrible question), used a design that would travel align the walls, past the river and to the broken line.  It picked up the repair module (shaped like a table) using a flat pad to slide underneath to pick it up.  It managed to do a 90 degree turn by following the wall (push sensors would tell the vehicle that it had in fact touched a wall).  It was clear that their design won out over everyone else’s, and they totally deserved the win.

Link: http://en.wikibooks.org/wiki/Serial_Programming/Serial_Java

Link: http://java.sun.com/developer/Books/javaprogramming/cookbook/11.pdf

The configuration that I used was that I had my computer connected to an XBee USB Explorer via USB.  On the other end was an Arduino Duemilanove powered by six 1.2 V NiMH batteries, and this microcontroller powered the XBee using its 5 V pin.  I compiled and downloaded the program at the bottom of the article to my Arduino and I tested it using the Serial Monitor that comes with the Arduino IDE.

Even though the test program is simple, it shows that a wireless link can be made between the computer and the microcontroller, meaning that the microcontroller can process computer input to do even more crazy things.

Link: http://forums.trossenrobotics.com/tutorials/how-to-diy-128/xbee-basics-3259/

http://www.ladyada.net/learn/arduino/