# Project Report  17 - BME680

## Purpose

Target of this project is to measure environmental data (temperature, humidity, IAQ) with an IoT device (ESP-8266 based) and several sensors connected via I²C. Detailed information can be provided in case of necessity.

## Hardware Setup

The main board builds a custom PCB with an ESP-12f, some DC/DC unit for stable 3.3V power supply, a USB-2-serial interface and some other peripherals quite similar to e.g. the [Wemos D1 mini v2](https://wiki.wemos.cc/products:d1:d1_mini_pro). 

The BME680 sensors is connected via I²C over a GH 4-pin cable with 10 cm length. The sensor PCB is derived from the Sparkfun version [here](https://www.sparkfun.com/products/14570).

The system is powered by a 3.7V / 10000mAh battery. The board is equipped with a charging unit and some of the here logged systems were charged during the data gathering for this report.

A DS3231 real time clock is connected over I²C for accurate measurement time intervals. 

## Software 

The software you find attached to this report is a stripped down but functionally equivalent to the version used for data gathering. 

### BSEC Version

BSEC_1.4.7.4_Generic_Release

# Measurements

- 15 systems (i.e. 15 BME680 sensors) were setup close to each other (on one desk)
- The BME sensors were configured to measure every 300s.
- The configuration applied is linked in the code. 
- The sensor states were cleared/reset simultaneously approximately 1 day before the data gathering.
- The location was an open office area in a private home. A kitchen was approximately within 10m distance. The sensors were not moved during the data gathering.

# Results

All data is stored in device specific csv files and in one accumulated excel sheet. The ID for each sensor is a 6-digit hexadecimal code. 

The csv is ordered like follows

| excel-time | unix epochs | battery level | n/a | n/a | n/a | n/a | n/a | temperature | humidity | iaq | static_iaq | iaq_accuracy | co2_equivalent | breath_voc_equivalent | gas | pressure | n/a |

The excel sheet with its pivot charts speeks for itself.

Some screenshots supplied in this report are based on the same data, but taken from an elastic stack server handling the overall sensor data.

# Revision

1. v1.0.0 | basic report
2. v1.0.1 | 1st review