The main goal of our CanSat is to make a satellite capable to measure pressure, humidity, radiation... so we can be able to know if a concrete planet can be habitable.
If you dont know what a CanSat is, it's a little satellite with the size of a soda can, if you want more information you can click here.
Step 1: The Components
All the components you need are the following (prizes are in the last image):
-LoRa T-beam TTGO GPS, it is a ESP8266 tracker board with both a LoRa radio and onboard GPS.
-Module LoRa TTGO OLED Screen, it is a LED Display where all the information that the CanSat gets will be shown.
-BME280 Digital Sensor, this is the sensor that is going to measure the amount of humidity and pressure.
-SD 8GB card, where all the information received is going to be saved.
-Geiger Counter, with this we will be capable of measure the amount of radioactivity around.
-PLA Filament, with this material the CanSat is going to be made.
-Some little screws are also going to be needed.
Step 2: 3D Model of the CanSat
To make the case of our "CanSat", we started by using an already made model: Canduino (http://canduino.eu/).
We have used this model and we have adapted it to our necessities. First of all, we printed it with our 3D printer, to see how it was and make sure there wasn't any type of problem. Once we saw that there wasn't any error and it had the correct size according to the contest's rules, we made or own copy and used Blender to put our name into it.
On our first try we saw that the temperature was to high and we thought that the problem was that too much heat was inside the CanSat, so we dicided to make some holes on the bottom part so air could enter inside it.
Step 3: Crafting the Parachute
The parachute we made has two main characteristics:
- It has very bright colours so the localization of the satellite can be easier.
- It reduces the falling speed of the satellite to 6-12 meters per second.
- It was made with an umbrella.
To archieve this we started looking in the internet and we found an we found out the formula on this webpge, and we also saw that the lenght of the strings that join the parachute and the satellite have to be around 1,3 and 1,5 times the diameter of the parachute.
When we made our first try we noticed that the strings were sometimes tangled between them so we made ourselves a little disk that separated all of them (see images).
Step 4: Data Transmission
We've choosed to use LoRa because we can recieve information from 10km long, the bad thing about this is that it has a slow transmission speed..
We have also choosed 868 MHz frequency because is the most common on technology.
To receive the data we have a "Yagi" antenna so we can adapt it to our receiver down, you can see a pretty similar one in this link: http://bit.ly/2DGlI6V
el almacenamiento de datos redundante explicado anteriormente.
Step 5: Saving the Data
To make sure we dont loose anything, there are 3 different ways of saving the information that we receive:
-First, our satellite has an internal memory called SPIFFS inside the ESP32 that allow us to save 4 hours of data.
-Second, we have a microSD that saves it.
-And finally, the base station sends all the information via USB to a computer, the program called PuTTY saves all the informatio inside a Text Document.
All this different places allow us to have access to the data in case of a crash or any kind of problem, so if anything happens we can still have it.
Step 6: Secondary Mission
Radioactivity is a silent contamintion and sometimes letal. We can find lot of radioactivity in the air, because of natural causes or because of artificial ones like escapes in installations. We can't see, smell it or hear it, thats why is so dangerous.
A business called FUNTECH knew about our project and gave us a GEIGER counter. We used a CURIE plate to detect the levels of radiation. It can be progemmed by USB and it can sound every time radiation pass the limits that we establish.
We have also incorporated a GPS so when the satellite is launched, we are able to find it more easily.
Step 7: Code of CanSat
This is the code that we have used to make our CanSat be able to measure all everything and send it to the Lora.