⚫ Materials:
➜ 2- Raspberry Pi 4 Model B 4GB RAM.
➜ 1- Box.
➜ 1- USB mouse.
➜ 1- USB keyboard and hub.
➜ 1- Micro HDMI cable.
➜ 1- Raspberry Pi Charger.
➜ 1- SD card
➜ 1- Raspberry Pi 4 Armor case.
➜ 1- Particulate matter sensor breakout.
➜ 1- User Guide.
➜ 1- USB-C power supply.
➜ 1- Particulate matter sensor with Cable.
➜ 1- Fancy environmental sensors and gorgeous little full color LCD.
⚫ Methods:
➜ During recent years, both the cities of Barcelona and Madrid have made important changes in pursuit of improving air quality, such introducing LEZs, reducing of space for vehicle circulation, forcing greater mobility by bicycle, introducing shared transport systems, and other such measures.
➜ These are some of the methods the cities used to prevent air pollution: First, a filter sampling for PM2.5. The subway stations were selected in the context of the IMPROVE LIFE project. The nine stations are located in different neighbourhoods in the metropolitan area of Barcelona and have contrasting designs belonging to the different lines. Eight stations encompassed platforms in double tunnelled subways that could be separated or not by a wall. They have a mechanical ventilation system that introduces outdoor air to the platforms, and extracts air outside trough ventilation grids in the tunnels. The modern Collblanc station has the platforms along a single track in a single tunnel that is separated from the rail track by a PDS with independent ventilation systems for tunnel and platforms. PM2.5 was collected on pre-cleaned quartz filters by means of a high-volume sampler from 5 a. m. to midnight (subway operating hours) at a sampling rate of 30 m3 h−1. Field blanks were taken at each station. After sampling, the filters were stored in aluminium foil at 4 °C before analysis. The Hi Vol samplers were placed at the end of the platforms behind a light screen for security protection.
➜ Noise exposure was estimated using Barcelona's strategic noise map. The daily average noise level (dB) at the street nearest to each participant's residential address was registered. A descriptive analysis of the clinical and demographic variables was performed, calculating percentages for categorical variables and mean with corresponding standard deviations for quantitative variables. A bivariate analysis, using Chi square for categorical variables and t-test for continuous variables, with their correspondent non-parametric testify needed, was performed to compare AIS (acute ischemic strokes) and TIA (transient ischemic attacks). Stratified models were fitted to evaluate whether the association between pollutants and risk of stroke symptom onset differed by the presumed stroke etiologic, residential NDVI (above versus below median) and residential traffic noise (above versus below the median).
〰 Some vocabulary we learned 〰
➜ Modprobe: The modules are independent units or drivers of the Linux Kernel (Nucleus). Probe is capable of reading the current level. A series of about 40 high (1) and low (0) voltages are generated from DHT 21. These voltages are read by a microcontroller. It is a binary signal with a length of 40 bits, it is 5 bytes. The first 2 bytes are the humidity, the next two contain the temperature data, and the last byte is like a check digit (cheksum)
➜ DHT22: It is a slow digital sensor that needs 3-4 seconds to measure the data. The DHT22 library, which can be in different languages, is what transforms all these languages into numbers. Find out if DHT22 is a resistive sensor or what type it is. (Recipe 13.1) Monk. It may be necessary in some case to add a ceramic capacitor without polarity (330nF), (There are some larger capacitors that are cylindrical that have polarity are mF) What a capacitor does is save the electric charge (couloms) and then release them.
➜ Resistance: reduces the number of electrons reaching a site. are regulatory elements
➜ The GPIO pins are analog, and the sensor is digital. To solve this, an analog digital converter (ADC) is used. The most widely used is a 12-bit adafruit sensor.
➜ The red wire is always current. The black wire is where the ground is connected. The white / yellow / orange wire is where the data flows. In the case of the rasberry pi, the GPIO 4 is used as a data pin. In modprove, pin 4 is the data pin by default, but you can change the code by writing sudo (superuser) nano / boot (boot) / config.txt (nano, which is a code editor that is by default in rasberry pi) GPIO PIN = 4
➜ Git: is a version control software that works with the command line.
➜ Github: is a software that allows you to use git technology in an easier way online. git github Look at the second command line book and practice free DHT22 installation.
➜ 1-wire protocol technology, one-wire protocol. It is called like that because there is a data cable that is the only one that has data, because the other two feed the circuit. that's why the DHT22 has 3 legs.