The Project

The NEMESYS Experiment is primarily composed of modular devices, because one of the aims of our project is to create something easy to use and replicate, possibly not too expensive. This way, anyone could use the experimental setup we propose to gather data while at high altitudes. Data could be then even collected on a single website, such as this, and used to map cosmic radiations all over the world. The experiment consists in:
  • a set of sensors used to gather data about the whereabouts of the whole experimental device (such as position, temperature, pressure, altitude)
  • a sensor dedicated to lightning detection, which is an atmospheric event that may cause the generation of a large number of particles that may impact the memory
  • a set of memory devices that acts as a sensor of the impact of cosmic radiation or particles on it
  • several microcontrollers that can interface with the sensor in parallel (to reduce scanning period), and a microcontroller to act as host for the others and as an interface between the experimenters and the whole experimental device

Components

The experiment is composed of:
  • Raspberry Pi: it communicates with each Arduino Uno, gathering the data collected by the sensors and saving it in a memory card; it constantly checks the Raspberry Pi Camera; it's the main link between the outer world and the experiment, thanks to the ethernet link and the up/downlink provided by BEXUS on the balloon's gondola
  • Raspberry Pi Camera: is used as a sensor for cosmic radiation and particles, since it is obscured (is not affected by light)
  • three Arduino Uno: each of them acts as an interface between the sensor and the Raspberry
  • GNSS module connected to a passive antenna: needed to provide real-time position
  • an altimeter/pressure sensor, with integrated temperature sensor
  • lightning detector
The whole experiment will be enclosed in an aluminum box, except for the antenna and the ethernet and power links, further surrounded by insulating material, so to keep the electronic devices at a sufficient high temperature for them to operate correctly. In fact, temperatures outside might reach -40°C at the altitudes the experiment is going to reach.

Microcontrollers' Operations

The Raspberry Pi periodically checks how many event it has counted in the Camera. While it counts the events, it processes incoming data from all the other microcontrollers and stores it. A fraction of the data depending on the shared ethernet link is sent through the downlink to a computer that analyses it and publishes the results on the website. One of the Arduino Uno is devoted to repeatedly checking the memory array and resetting it. The memories reset in a predefined pattern and, when checked, all bit errors (bit-flips) occured are counted and stored as data. The altitude/pressure sensor is used to double check altitude data obtained from the GPS module and gather information about temperature, so that ground operators can keep under control whether vthe conditions the devices are working in are acceptable.   The GPS module obviously provides full 3D Position so to enable the experimenters to correlate position, time and occurring events as accurately as possible.
 



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