The flight board, which is considered the backbone of the entire S4 payload, is a Printed Circuit Board (PCB). The flight board provides the foundation that keeps all the components firmly in place. It also provides a route for the power and information to travel between the components. This is achieved through a system of wires, called ‘traces’, that are printed directly on the board. The flight board is the only component in the S4 Payload that is not off the shelf, but rather designed for the projects they are needed for.
The base payload components attached to the flight board include:
The Arduino is the main microprocessor attached to the flight board. It is responsible for the data collection from the various components, formatting that data and sending it to the WiFi and SD card devices for the transmission and storage. All of the code that operates the payload will be handled by the Arduino.
The Wi-Fly chip allows the real time communication between the payload and the base station, using 802.11g wireless network protocol. This is the same type of wireless communication that is used in your home or classroom to provide internet access to your computer and smartphone. The chip allows two-way communication between the ground station and the payload in flight.
Open Log SD Writer
The Open Log chip stores data from the sensors onto a Micro-SD card, same as the chip used in many smart phones. This ensures that even if the ground station temporarily loses the WiFi connection with the payload the data will be saved. This also allows students to obtain useful data from the payload if they haven’t yet integrated the Wi-Fly card, or if they don’t have a local WiFi network with which to communicate in their classroom.
The GPS (Global Positioning System) chip provides the three dimensional location (Altitude, Latitude and Longitude) of the S4 payload as a function of time. These data are stored with the data from experimental sensors so that they can be correlated to return scientific results.
The S4 payload uses a 2.4 GHz antenna to communicate through the WiFi chip to the ground station computer.
Logic Level Converter
The logic level converter is an electrical device that converts the high (9V) voltage from the battery to the 3.3 V level needed by the Arduino and the other flight board components.
The flight board includes a voltage regulator to ensure the Arduino does not exceed 3.3 V.
There are several different sensors that can be added to the Flight Board based on the experiments being conducted. Here a few of the different sensor components that can be attached to the flight board:
The accelerometer sensor measures how fast the payload is accelerating in any direction, returning values for each of the X, Y and Z axes. It measures static acceleration due to the Earth’s gravitational force, as well as acceleration resulting from motion (units in g’s). This data can be used to determine useful information about the flight path of the payload or to provide the orientation of the payload.
Even though the accelerometer only provides relative information, it does not require GPS signals from external satellites. The shield is labeled with a diagram depicting the actual orientation of the X, Y, and Z axes. Its performance is limited to 16 times the g-force from the Earth’s surface, which may be exceeded in some high-powered rocket launches.
The magnetometer measures the strength of magnetic fields along 3 axes, returning the strength of the magnetic field in each of the X, Y and Z axes (units in mG). The shield is labeled with a diagram depicting the actual orientation of the X, Y, and Z axes.
Barometric Pressure/Temperature Sensor
The barometric pressure and temperature sensors are integrated into a single device which returns two values, one for pressure and one for temperature. This barometric pressure sensor covers a range of pressures from 300-1100 hPa with accuracy down to 0.03 hPa (1 hPa = 100 Pascals, and 1 Pascal = 1 1 N/m2). The temperature is recorded in Celsius.
The humidity sensor measures relative humidity (RH) with temperature compensation. The device also consists of a standalone temperature sensor output, which is measured in Celsius.