mobile senseBox

This is some Arduino code for GPS tracked senseBoxes. They have an SDS011 particulate matter sensor & HDC1008 Temp & Humidity sensor attached and transmit their measurements to opensensemap.org.

There are multiple variants to make use of various hardware I had available, and to evaluate different use cases and workflows of data transmission.

Each sketch folder has its own readme with (more or less) detailed documentation. The libraries folder contains all code that any sketch may depend on. The the most simple solution to use these sketches is to make a backup of your existing ~/Arduino folder, and clone this repository there instead:

mv ~/Arduino ~/Arduino.bak
git clone https://github.com/noerw/mobile-sensebox ~/Arduino

Hardware

The microcontroller & communication protocol differs for the sketches, but all variants require a GPS device, a microcontroller with I2C, 2 UARTs (or some sort of software UART), as well as an Novafit SDS011 & a Bosch HDC1008.

My builds of all these setups are powered by a 5.6Ah LiPo through an Adafruit LiPo charger via USB, and enclosed in a 15x8x8 case. The humidity sensor is included for reference, as the SDS011 only provides valid data at low humidity. The sensor is enclosed within the case (which heats up quite a bit), which makes the measurements quite inaccurate, they should only be treated as approximations. This setup is quite suboptimal for regular deployment (eg. daily commute by bike), see Future Work.

./lora-gps

Arduino Mega + Dragino LoRa & GPS Shield + senseBox Shield (SD card)

• transmitting data via LoRa to opensensemap.org through thethingsnetwork.org (details in SETUP.md)
• additionally saving to SD card if no LoRa coverage is available
• Arduino Uno should work as well, you need to play around with SoftSerial i guess..

./esp8266-gps

Wemos D1 (ESP8266) + senseBox Shield

• stores measurements locally on 3MB SPIFFS, and uploads via WiFi when available
• requires installation of ESP8266 Arduino SDK, see esp8266-gps/README.md
• senseBox shield only used for ease of use with JST-connectors, not needed

./sdcard-gps

Arduino Mega + senseBox Shield

• logging to SD card, manual upload to opensensemap.org

Future Work

• Evaluation of SDS011 in a mobile environment: Influence of wind, sunlight, vibrations, differing orientations

• Averaging of measurement values

  • tradeoff: less outliers <-> smaller spatial acurracy

• Improved case

  • power switch on the outside
  • simple, quick mounting on a bike
  • status LEDs about connectivity, GPS
  • more neutral placement of humidity sensor
  • all-weather proof

License

• sketch directories: MIT Norwin Roosen
• libraries directory: see each subdirectory