Blog - Sketching with Hardware

The last day

Published on: | Author: Ruben Lenz | Categories: 2018a, Daily Logs, Final Presentations

tl;dr: Here is the last day in 15 seconds:

Munich, 23th February, 3:30 am. A quiet and cosy neighbourhood in the suburban, western part of the city. The seventy style clumsy grey block buildings lie next to each other in a cold winter night with hundreds of hundred people hidden inside of them. Only some very rare bright windows give a hint of life in this lonely place and time, before the swarm awakes and the people slowly start to move, somehow directed like ants.

But suddenly a heavy scream breaks through the silence.

I find myself sitting in my bed, completely wet and heavily breathing. Panicly looking around I notice I’m at home and alone, apparently safe. I check the clock, still 4 hours left until the end begins. I desperately try to get some more sleep and after some time, the most frightening and vicious monsters of my imagination start to rage in my dreams again… It is:

OK, to be a little more realistic: The worst thing about the last night before the final day of SWH for me was its shortness. Since the start of the course I somehow didn’t manage to get more than one night of enough sleep, a phenomenon I did also feel some of my colleagues had as well and while browsing through the blog entries of the last years I also encountered some similar experiences.

But when I arrived at our workroom the general mood seemed pretty good and relaxed. Our project was almost finished and just needed some fine tuning, the other projects were pretty much finished as well. So I used the time to work out and write down the questions I wanted to ask the other teams in order to get a look in their current status and final thoughts about SWH as detailed and differentiated as under these circumstances possible. But appropriate for the general flair of SWH the questions and conversations changed over time and not at any given moment was enough time for long conversation, so I can’t quite provide total consistent explanations now.

What I wanted to know from the teams was their current project status, the main problems, they experienced during SWH and how they fixed it, and what lessons, experiences, feelings etc. they will take home with them. Here are the results, chronologically sorted (I will skip a description of the projects here as you can find them in a separate post or the previous days):

Team 5: Toadale Catastrophe

Time: 9:45
Stress level: 2

Current status: Everything functioning fine, trying out some sound effects and looking forward to the presentation, for which they we’re already making some plans.

Team 6: Watertag

Time: 9:50
Stress level: 1

Current status: Project’s working, so testing, fine tuning and painting was done.

Main problems: Finding a good way for a proper and detailed triggering of the west when it gets shot, but not through the movement of the person and the thereby occurring impulse. At first, a pressure sensor was used, but this wasn’t sensitive enough, thus it was finally replaced by a piezo sensor. Another point that needed a lot of effort was the complete water resistance of the project, which was achieved by lots of foil, hot glue and tape.

Team 8: autoSOWmatic

Time: 10:00
Stress level: 1

Current status: Final assembly and testing.

Main problems: The connection between the Arduino and the Android smartphone. The interface proved to be pretty user-unfriendly, hence also the debugging was quite a torture. Beside that, designing and implementing the mechanics wasn’t too easy as well. Moreover, the concurrency of the whole program was tricky to realize: A timer method had to be built, which forced very quick switches between the execution of the programs tasks to fake real concurrency.
These problems led to the impossibility of finishing the map-driven activation of the seed spreader, on the other side, the spreader itself was easier to construct, than the team thought: Only one motor instead of two was necessary.

Team 1: Guarden Zwerg

Time: 10:25
Stress level: 3: Pretty relaxed, but a little nervous because something could always go wrong.

Current status: When I met the team their project was quite completed, so they were just choosing some cool sound effects to greet the intruders. These are the real enjoyable and funny parts of SWH.

Main problems: One of Zwergis main problems was his not reliably working water pump, presumably because of an intermittent contact or defective wire, but the problem has never really been clarified. A good example for a typical annoying part of SWH: Loosing a lot of time and energy on finding and repairing nasty and mysterious little errors.

Team 1 has also had some mechanical trouble: The attachment of Zwergi on the motor was difficult and his box was pretty narrow for all the electronics and the pipe.

Little place in little Zwergi for lots of electronics

Takeaway: What team 1 took home from the last week were crafting and motor skills.

Team 3: Hanging Moss Plotter

Time: 10:40
Stress level: 1

Current status: Project is working, all that was left to do was some calibration and they also began with their preparations for the presentation, like a duct tape writing on the ground and a laser cut sign.

Main problems: The stepper motors were too slow and weak, which was kind of hard to predict at the beginning and therefore not easy to evade or solve. So there had to be a lot of trying and testing.

Takeaway: If they had to rebuild the project, they would use a pump instead of a spray bottle and they would spend more effort in planing and for example reading libraries. One important realization was, that literally everything can be solved with duct tape, glue and the laser cutter.

Team 2: Birdinator 4999

Time: 10:50
Stress level: 1

Current status: The light sensor/photocell was currently delivering impractical values, so they were integrating a higher resistor.

Main problems: Similar to team 1, they had built their project a bit too small, so a lot of patience and dexterity had been required to set up and complete all the parts. It also took them quite some time to properly design and finish the flyswatter. The first version of it was working, but quite complicated and too big. So the team had to design another one, which now was directly driven by the motor and laser cut gear and not by a rubber band.

The old version of the flyswatter…

New flyswatter

Takeaway: The next project would be bigger in general and laser cutting is killer.

Team 7: The seedling sitter

Time: 10:55
Stress level: 1

Current status: Pretty much nothing to do. The fine tuning had already been done before, for example slowing down the request time of the soil moisture sensor in order to reduce its wearout.

Main problems: Pulling the lamp up and down was quite difficult, because the servo the team had planned to use wasn’t strong enough for the pretty heavy lamp, so a pulley had to be built. Furthermore the pump also needed some time to work fine and the wiring wasn’t too easy as well, but it all worked out in the end.

Takeaway: The team very much enjoyed the atmosphere of the last days, that they described as kind of an open living room. This gave them motivation to do some more sketching in the future, though they would design the circuit diagram in advance and would also use a different solution for the movement of the lamp.

Team 4: HANS

Time: 11:00
Stress level: 7: Problem!

Current status: Our board carrying Horst (our cactus) didn’t move anymore! While interviewing all the other teams and looking at their projects I nearly forgot our own and now its main feature stopped working! At first, we couldn’t really find the problems cause and thought of replacing the motor.


But after some time we realized, that the board was pressing down on the gearwheel of the stepper motor and after some bending and many, many tries the motor was operating more or less correctly again.

Takeaway: We found it amazing, in which short time you can build a project consisting of many ideas that at first you have no clues how they could be realized. I also really liked, how fast we could get into electronics and mechanics and suddenly a LED on your Arduino blinks, which really feels great at first! This was possible by the help and collegial support of Beat and Bernhard, who had a lot of patience with us.

The presentation

Finally, it’s 12 o’clock! The first guests, like professors and doctorands are arriving and the tension rises one last time for the crucial minutes of the last week. Each team now successively presents its project idea, implementation and gives a short demonstration, which was interesting and fun for the guests as well as for ourselves. Kind of surprisingly almost everything went fine, except for team 8 (autoSOWmatic), whose spreader wouldn’t spread. The android interface bamboozled them one more time :-(. But after some upset and a lot of trying they made it operate again and even our Horst drove in and out all the time, although I didn’t really know why…

The end

After this relaxed last hour, we started to clean everything up and after a short time it all appeared pretty empty. While we then went to a nearby restaurant to have some lunch (and beer and schnaps, thanks Bernhard!) the first people already started to sort and pack everything for the relocation of the academic chair. In the evening, when I finally got home after many relaxed conversations, I felt exhausted, but happy.

As excepted, this was a still quite stressful but overall very funny and satisfying end of the project. I have got the feeling, that most of the participants have learned a lot in a short time; many of us have made great progress in our mechanical and electronic skills and gained quite some skills in fast and dirty fixes and workarounds. So all of that was also a very creative process.

It was for some of us a little hard to deal with the fast nearing deadline and the pressure to complete the project. This sometimes led to the fact, that we had to let go of some of our ideas, what has been kind of sad in some cases. Also in nearly every team there was some anger about small nasty problems, that took away a lot of patience and time, like mysterious errors or searching for the right equipment or material.

So in the end we all knew some stuff, that could have been done easier and/or better, but despite that all, everything vital worked out somehow and there were some great results in the end and a lot of stuff to remember and think about for the future. And the most important thing: We had an exciting and delightful time due to the good atmosphere and especially the friendly, patient and collegian nature of Bernhard and Beat, which I want to thank here cordially! Great fun to any future participants and peaceful nights for me and everyone else :-).

linked categories 2018a, Daily Logs, Final Presentations


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