A strange kind of holiday

It all started about two weeks ago when my wife discovered water on the kitchen floor that kept coming. The plumber who came immediately, found out that two parts of the waste pipe shifted out of each other, leaving a gap open. He told us that this must have happened two or three weeks earlier. During this time, the waste  water filled up the base of the kitchen, which turned out to be water tight. He sucked out all the water, and left one part of the base open, so that some air could ventilate. He also told us that probably we would get a giant hair drier installed to get the rest of the moisture out. Nothing happened for more than a week. The smell was disgusting, and we apologized to the guest at Levin’s birthday party. Our neighbour told us that the same thing happened to them last summer, and that they had 40° for some weeks in their kitchen as a result.

When the craftsmen came to inspect the kitchen, they discovered one giant mold fungus. Immediately, they sealed the kitchen from the rest of the flat and all the cupboards. They started to disassemble the kitchen and removed the appliances. Most of it would be replaced. They sprayed some poison to contain it. After they told us the whole flat would have to be sprayed, the house management together with the insurance decided that it would be best for us to move to a hotel for two weeks. The insurance organized it for us. It appears they asked some other hotels first which were fully booked. So we ended up in the best hotel in town, the Waldstätterhof. The breakfast is included, and it is a very nice and delicious buffet. The funniest part for us was the Prosecco bottle next to the fruit juices. We usually don’t make holidays in such exclusive places, but we know it from special events such as the Musical we go to almost every year.

The insurance even pays for the additional costs we have because we can’t cook at home. But he asked us not to eat at the noble restaurants downstairs all the time. Of course we don’t want to exploit the situation, but because Levin had a surgery the day before we had to leave home, we cannot go outside all the time. The first day we ordered some food from lieferservice.ch at seewendays.ch that I could pay with BitCoin. The second day, I bought a warm chicken in the local grocery store. For the rest of the week, Mirella organized to have the meals delivered from the hospital. I must confess, it feels awkward to walk into the lobby of a four star hotel with a hot chicken in the backpack to eat at the room. But yesterday we went to the restaurant downstairs for once. It wasn’t cheap, but delicious.

The kids enjoy the adventure, especially because we rarely have so much time to play with them. Levin got a dinosaur skeleton to excavate from Santa Claus the day we left. So we went to the big hotel terrace to carve out the artificial bones from the enclosing gypsum. He was totally excited as the bones started to get released. Yesterday, we assembled a KAKU robot. Putting the parts together was easy. I had to do most steps, but the boys could help here and there. Noah walks around full of pride with the enclosed emblem. As all the manuals and information I found are in Chinese, its not always easy to find the required information. But the programming system ArduBlocks is exactly what I have been waiting for since I learned about the Scratch programming language.

 

Robot Arm part 1 packaging and simple manipulation

Another project that I had in mind for a while was to experiment with robot arm path planning and inverse kinematics. If you don’t know what that is, think about how robot arms could be programmed. The simplest form would be capture and replay, in which you have a controller which which you record how you manually move the joints. The robot can then replay the movements. We humans have developed a good  intuition for moving our body parts and grasping, but when it comes to formally describing what you do with the joints of your arm, it quickly becomes difficult. My younger son is in the phase of learning to grasp right now, and it’s amazing to see how the eye arm coordination evolves. The second approach would be to program it like a CNC milling machine with something like G-codes.  This is a bit more general and more exact, but it’s also more difficult to do collision avoidance. And it’s complicated to calculate as most joints tend to be revolutionate. Both these approaches are only suited for repetitive tasks often found in industry automation, but completely unsuited for robots in dynamic environments. Now with inverse kinematics, you can tell the robot where the arm should move to in cartesian coordinates, and it does all the arm geometry calculations and positions the gripper to the correct position in the desired orientation. Maybe there are obstacles in between the current and the target position. To navigate around these, you also need path planning. That is usually done in configuration space. Real robots have also to care about dynamics such as inertia, but I won’t go that far.

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