This Readme file contains information on the building and production of a Oregon SensOR box. The original information is found here. Kairos here! I am building this as an expansion of a project I did last summer (electrical documentation can be found there for the SPS30 sensor). I was supposed to do this like 2 months ago but I took too long on the autosampler </3.
Sensor interface for real-time particulate monitoring using the SPS30 and Raspberry Pi, with CSV logging support.
| Component | Description / Model | Notes | Have? |
|---|---|---|---|
| PM2.5 Sensor | Plantower PMs5003ST | Measures particulate matter | ☑️ |
| PM2.5 Sensor | Sensirion SPS30 sensor | Measures particulate matter | ☑️ |
| Power Supply | RID-65A Meanwell (5V/12V) or RT-65D (5V/24V/12V) | Provides power etc | ☑️ |
| Computer | Raspberry Pi 5 | Main system controller | ☑️ |
| SD Card | SanDisk 64 GB SD Card | Storage for OS & data | ☑️ |
| Auto-Zero Valve | US Solid Motorized Ball Valve | Valve | ☑️ |
| 2x6 Terminal block | Amazon Link | Makes wiring easier | ☑️ |
| Heating Element | Amazon Link | Heating | ☑️ |
| GPIO Terminal Block w/LED | Amazon Link | Easier GPIO wiring + indicators | ☑️ |
| Relay Board / RPi Hat | Amazon Link | Turns stuff on and off | ☑️ |
| Diaphragm Pump | Supplies clean reference air | ☑️ | |
| Rheostat | Adjusts current / heating power | ☑️ | |
| Sensor Box | Enclosure for system | ☑️ | |
| 80 mm computer fan | generic? | Fan | ☑️ |
Plus wire, connectors, filament, screws, tools, etc?
It's got circuits! I need to apply Ohm's Law, Kirchoff's Laws, and power calculations... I can also write about how the particle sensors use optical scattering as a detection method (I think that counts?).
Plantower sensor pinout
| Physical Pin | BCM | Function | Connection |
|---|---|---|---|
| 6 | — | GND | Ground for ALL devices |
| 7 | 4 | GPIO4 | Button |
| 8 | 14 | TXD0 | Plantower #1 → RX (UART0) |
| 10 | 15 | RXD0 | Plantower #1 ← TX (UART0) |
| 11 | 17 | GPIO17 | Fan tachometer |
| 27 | 0 | TXD1 | SPS30 → RX (UART1 TX → Pi RX) |
| 28 | 1 | RXD1 | SPS30 ← TX (UART1 RX ← Pi TX) |
| 32 | 12 | TXD4 | Plantower #2 → RX (UART4 TX → Pi RX) |
| 33 | 13 | RXD4 | Plantower #2 ← TX (UART4 RX ← Pi TX) |
| 37 | 26 | GPIO26 | Plantower power (Relay1) |
| 38 | 20 | GPIO20 | Heater (Relay2) |
| 40 | 21 | GPIO21 | Zero pump (Relay3, NC) |
| 40 | 21 | GPIO21 | Valve (Relay3, NO) |
Note: we are skipping UART2 since we are using gpio 4 (physical pin 7) for something else
/boot/firmware/config.txt
enable_uart=1
dtoverlay=uart1
dtoverlay=uart4Use
ls /dev/ttyAMA*to make sure all the desired ports (0,1,4) are available. When sensors are connected, check output with
sudo cat /dev/ttyAMA0
sudo cat /dev/ttyAMA1
sudo cat /dev/ttyAMA4Particle sensors (3x), level shifters
The SET and RESET pins of the Plantower sensors... oopsies!
Fan, Pumps, motorized ball valce, heater strip+ (rheostat)