Blog October 2021 - June 2022

Yesterday were the presentations on the analysis of the collected data. We were one of the few teams that had an almost complete data set and were able to deliver solidly. One and a half hours later the jury announced the result: 2nd place!!! We are runner-up of the German CanSat competition 2021/22. We are very proud of this result. The last 8 months were a nice but also challenging time. We would like to thank all our sponsors for their support during the competition, but also everyone who kept us motivated during the competition, so that we never gave up, no matter what problems we had to overcome. Maybe we will see each other again for the next competition!

Today at 17h was the livestream of the CanSat launch. We are happy to have brought this project this far. However, we are disappointed that the launch did not show how our CanSat was loaded into the rocket and dropped down. I guess we will have to rely entirely on the data we have collected and probably do not have a video showing our CanSat falling. Nevertheless, we are happy that all CanSats could be recovered. In addition, we are now anxiously awaiting the arrival of the CanSat with its data-let's see what we can get out of it!

After we completely rebuilt the CanSat on Saturday and on Sunday, today we did the functional tests and the finishing touches. We did all the functional tests and finished the CanSat today after we rebuilt the entire CanSat on Saturday. In addition, it was shipped on time. At the same time, we finished and sent off the user manual. So now we are looking forward to the conference and the launch campaign.

Today we thought again about the construction of our streamers. The last ones were not cut properly, so we couldn't find enough space in our CanSat. In addition, we had to think about how to roll the streamers-because we would never have been able to fit the 4 streamers needed for the main recovery system into the volume for the recovery system in 4 individual rolls. So we came up with a technique for rolling the streamers. So all 4 streamers are rolled up together and placed on the CanSat.

In addition, we finally got to work on the hull design and printed it. The hull is outside in the colors of the Ukraine. The design was strongly dependent on the streamers: Since we need a height of 6.5cm for the streamers, the hull had to make room for 2cm in addition to the estimated height of 4.5cm due to competition rules. We were able to do this because our CanSat itself is only 9cm high. This allowed us to add an intermediate floor at 9.2cm height of the hull, on which the strommer will rest.

In addition, we started today with the animations for the video and for the presentation.

Today we looked for some inspiration for the video and the final presentation and planned the course of the next two weeks-it will be stressful, especially because the exam period starts.

Today we had a meeting with the Lord Mayor of the city of Bad Homburg, Mr. Hetjs. To this we presented the CanSat competition and our work of the last five months in this competition. Not only did he promise us access to the roof of the city hall in case we need to do further drop tests, but we are now also allowed to welcome the city of Bad Homburg as a new sponsor of our team. Of course we are very happy about that. The roof of the town hall could also be useful for us in the future, but maybe we'll have something even better soon - you can stay curious about that.

Then today we were busy all morning and forenoon saving leftovers.

A BNO still works. A BMP does as well. The GPS with the broken PCB-it still responds, but we are reluctant to use it in the CanSat. We have therefore ordered new ones. The Picos also only had problems with the flash. We were able to fix those with a flash-nuke. At least that's good news. Nevertheless, yesterday was a massive setback. But we are back on track. We now have stricter testing guidelines in place so that something like this won't happen again.

We're now waiting for the new GPS modules and hope to get it all done before Monday.

We only got a little bit of trouble from the janitor for yesterday (sorry), that it was a little bit too long yesterday. We didn't program today after all-instead, a few mechanical adjustments were made: We replaced the threaded rods with 5 mm diameter steel rods with a thread cut in the top and bottom. In addition, the PCBs of our BMPs had to be filed down a bit-so nothing major. We also reworked the accumulator layer and the switch layer. Tomorrow these will be printed, and then the CanSat will be mechanically ready!

About the CanSat: Without the case, it is 10.5 cm high and weighs 202g (excluding the flowers). That's a bit too light, so now we have to come up with funny things for the weights. Let's see what we will find. But of course we are also open for suggestions.

We were back on the tower roof. Instead of the iPhone, we now used our Raspberry Pi Pico. We will only use the Raspberry Pi Pico from now on, for the following reasons: First, in the CanSat we will also have only one Raspberry Pi Pico available and the drop tests are therefore tests to see if the final CanSat will work. Second, during one of the drop tests, the flutter tape came off the protective cover and the case thus fell from the sky without any braking from a flutter tape. This was the last drop test for the phone, as it has never come back on since. Too bad.

But there is also good news: We have reached terminal velocity and that at exactly 11 m/s. With this we could prove simualtion values from OpenRocket and we have the first part of our recovery system. Our flow will be gigantic-4.5x0.45m-but we are happy about that for now. The only question now is how we can accommodate this amount of material weight-wise and folding-wise.

It's also good that we're done with the drop tests, because starting Monday the school will be a construction site-there's no more throwing stuff off the tower.

We have to thank the janitors who made it possible for us to do drop tests on a Saturday at the school.

A lot has happened in the last few weeks:

We have officially won Merck as a sponsor. The talks had been going on for some time, but now we are happy about the support.

In the last days we started to design the PCB's for the finished CanSat. We already have the main layer with the Raspberry Pi Pico, and our first sensor layer with acceleration, temperature, pressure sensor and GPS.

At the same time, preparations are underway for testing our braking mechanism: we have started to build a slingshot, with which we hope to be able to spin the CanSat high enough to estimate the fall speed.

There have also been some changes in the equipment we use: we have a new accelerometer and we have different radio modules.

Über die letzten Wochen hatten wir bereits einzeln angefangen, den Zwischenbericht für den CanSat zu schreiben. Pünktlich zum Ferienbeginn konnten wir also die zum Zwischenbericht notwendigen Materialien erstellen. Nach guten 11h Arbeit heute waren wir fertig. Damit können wir uns jetzt auf die Programmierung des CanSats konzentrieren.

We have a problem: we can't program the Raspi Zero well. So today we decided to switch to the Raspi Pico. This offers us some advantages: More I2C ports and less space consumption. We just have to see if we can still accommodate the camera as we had planned.

We have finished the cabling for the first layers. Now we can finally start programming the sensors. For this purpose, the CanSat is now with Boris.

The current cabling is only a temporary solution until everything is programmed. Then we want to solder all cables.

Over the week, some more progress was made: We thought about a mount for the Raspi Zero, and printed it. Today, the mount for the barometer and gimbal were developed. Over the week, we played around a lot with the school's 3D printer and made some improvements. Next is the design of the sensor layer, that is the layer of the air pressure and temperature sensor, the gimbal and the buzzer. 

In addition, we received another very important news for us: The award ceremony from the DLR wind turbine competition is coming up. We are very excited about the results

We had another meeting with the Orga team today. Our new idea is fine. So what do we have planned? 

We want to build the satellite in a modular way. To do this, we want to construct individual layers, each housing a part of the CanSat. As sensors we want to use the provided air pressure and temperature sensor, as well as a gimbal. The CanSat will then be intercepted and picked up in the air by a drone when we have the time. Currently, we are still thinking about a tracking mechanism that can be used to implement this accurately. The current ideas are either ultrasound, laser or computer vision.

We have a problem: We are not allowed to carry out our first idea of the Cansat in its current form due to legal requirements. Therefore we need a new idea. We already have one: We want to build a "normal" CanSat, which fulfills the primary mission. This should send the measured data only to a ground station. 

But that would be too simple. Therefore we want to catch the CanSat with a drone from the air and bring it safely to the ground. Whether we are allowed to do this will be decided next Monday. Nevertheless, we are already busy with the 3D model and the necessary calculations.

Therefore we have also changed our logo: We can no longer use the old one...

The setup of our test equipment begins. We need a non-motorized gimbal to program the directional control of the CanSat. It should only move in the desired direction. Normally, because of the symmetry of the setup, the CanSat would not tilt in a straight line, but in a rotational motion. However, this rotational movement is undesirable, which is why the canSat must be calibrated. We built the gimbal for calibration today.

It consists of 2 axes, so that it can tilt in all directions. It is also mounted on a rotatable plate, so we can compensate the torque of the rotor.

We also ordered the necessary parts for the CanSat.

The search for sponsors continues.