Last week, from Tuesday 4 January to Sunday 9 January, our focus was on completing the structure, circuit board and main software of the probe. For this we met partly in presence, while on other days we worked individually from home. By using our GitHub repository and some communication programmes, we were able to organise ourselves well. Unfortunately, we were not able to complete the CanSat before the end of the holidays as planned, because some orders for important components were delayed.
As far as the structure is concerned, we had the opportunity to manufacture the necessary metal parts for the lid and base plate of the probe. We chose aluminium as the material for these, as it ensures the required stability without adding too much weight to the probe. In addition, the use of aluminium in the hull had already proven itself in previous projects. There has also been considerable progress in creating a final structural design: Not only has the arrangement of the sensors and placement of the circuit board in the lower part of the CanSat been fully worked out, but we have now also been able to find a suitable solution for attaching the pumping system, especially the gas collection bags, to the outer hull. All in all, we will soon be able to finalise the planning of the structure and turn our attention to the construction of the entire system.
In the illustration, aluminium parts such as the recently milled lid or the three threaded rods that hold the individual segments of the probe together can be seen in grey.
Immediately below the lid, in blue, is the pump system, consisting of three two-way valves and the air pump itself.
Above the orange segment at the very bottom, which is the outer shell of the lower section, is the circuit board and microcontroller, also in blue. On the right side of the orange area is the on/off switch. For the sake of clarity, the sensor system and the outer shell of the upper section of the probe are not included in this illustration..
The planning of a preliminary board concept, optimised for the structural and technical requirements of our CanSat, was also completed at the beginning of the week. A cost-effective way to have this printed by a professional company is also already in prospect. However, we are still waiting for the expertise of a professional to have our design checked again.
After we found out during the calibration of our sensors in December that the response times of our temperature sensor did not meet our expectations, we ordered a different type of sensor early on and got it working this week. Whereas before we needed more than a minute for temperature fluctuations of several degrees Celsius to be displayed to one decimal place, with the new sensor this happens almost directly within a few milliseconds.
Finally, we have begun to merge the individual programmes of the various components into the main software programme and to incorporate them into the main programme flow. This will require some tests in the near future, which are aimed at determining some time values for controlling the pump system.