The brain of our balloon will have to read and record the data, and to intervene if necessary in case of problems
If you do not just go up, but you want to go higher than everyone else, then you have to start from the bottom, that is, from the gondola which will house all the artificial intelligence of your balloon.
electronic boards and sensors
Flight Controller: Arduino Mega 2560 R3
Weight: 37 gr Consumption: 50 mA
This board fully programmable in JAVA will be the brains of our balloon. It will read the data of all sensors once per second and record them on a micro SD card. Will also deal intelligently manage the flight and unhook the gondola from the balloon in case of low battery, internal temperature below zero, sudden altitude decrease, decreased share following the achievement of the highest attainable roof.
Outdoor Temperature Sensor: DS18B20 Probe
Weight: 20 gr Consumption: 4 mA
This sensor, is capable of reading temperatures in a range between -55 to +125 ° C.
Will come out of about 15 cm from the gondola and read the temperature changes during the climb to the 40,000 m.
Interior Temperature and Humidity Sensor: DHT11
Weight: 5 gr Consumption: 2,5 mA
This dual temperature and humidity sensor is placed inside the nacelle to monitor it's "health".
Thanks to it, in case of critical values, the controller will control the release of the nacelle to bring it quickly to the ground.
Air Quality Sensor: MQ-135
Weight: 8 gr Consumption: 180 mA
It's normal to hear that the air is the purest in mountains.
This air quality sensor we will see, how pollution changes with altitude.
It can detect: ammonia, aromatics, sulfur, benzene vapor, smoke and other harmful gases in concentrations from 10 to 1000 ppm.
Pressure Sensor: BMP 180
Weight: 2 gr Consumption: 5 μA
The pressure sensor BMP 180 reads differences in pressure between 300 and 1100 hPa, this means from -500 m to 9000 m, with a precision of 25 cm.
It will be used as a primary altimeter, from beginning of lift-off until completion of 10,000 m. Above this altitude, the data will continue to be recorded, but will take over as the primary altimeter another module, GPS.
GPS Module: NEO-6M UBLOX
Weight: 20 gr Consumption: 70 mA
This GPS module will be connected as the other sensors to the controller that thanks to it will read the data about the position. It will be continuously recorded on an SD card to store the track.
When the balloon will rise beyond 10,000 meters GPS will be used as a primary altimeter to determine the altitude.
Micro SD cards Reader / Writer
Weight: 6 gr Consumption: 2 mA
With this module we can store all flight data. GPS tracking, air quality, temperature and humidity will be recorded on a micro SD card.
The data on that schedule, are then physically recovered when the balloon will land.
Transmitter with Sim card: SIM900 GPRS SIMCOM
Weight: 45 gr Consumption: 1,5 mA
This module allows us to receive the data on the position when the ball, after the climb, will descend below the altitude of about 3000 meters.
Its proper functioning is critical to the discovery of the nacelle containing all the electronics and the valuable data collected. We are currently considering whether to install a second as a backup.
Weight: 9 gr Input: 2 Lipo = 7.4 v Output: 5V / 3A max
This voltage regulator is indispensable to operate the transmitter. This is because during its operation (the transmitter) it arrives to absorb 2A peaks, and it can not withstand voltages above 5V.
Weight: 47 grams each Power: 1.6W Voltage: 5.5V
We decided to also buy a pair of solar panels to have enough energy in case of batteries freezing / breakdown. They will be placed on the ship's sides.
Components are arrived, but before to write the complete code, I have to test the sensors one by one, to see if they work properly and figure out how to connect them.
You can find already tested sensors, at page below with instructions for use, and its code.