Update 'README.md'
This commit is contained in:
parent
d22963e249
commit
e80fd40194
28
README.md
28
README.md
|
@ -1,7 +1,16 @@
|
|||
# Readme
|
||||
# ESP32-based Environmental Sensor
|
||||
Author: Jannik Beyerstedt
|
||||
**license:** GNU GPL v3
|
||||
|
||||
A simple temperature and humidity sensor node using an ESP32 and a Si7021 sensor element running of a 18650 LiIon battery cell.
|
||||
The sensor outputs the data to an influxDB instance, which must be reachable via HTTP.
|
||||
|
||||
To save energy, we use a lower CPU frequency.
|
||||
But this requires compiling the core framework again with the changed settings (see below).
|
||||
|
||||
This repository contains the code running on the ESP32, as well as the PCB and case design.
|
||||
|
||||
|
||||
|
||||
## Dependencies
|
||||
Prepare toolchain (macOS):
|
||||
|
@ -43,7 +52,8 @@ git clone --recursive https://github.com/espressif/esp-idf.git
|
|||
```
|
||||
|
||||
|
||||
## Checkout this project and configure arduino-es32 with esp-idf:
|
||||
|
||||
## Checkout this project and configure arduino-esp32 with esp-idf:
|
||||
```
|
||||
TODO!!
|
||||
|
||||
|
@ -71,3 +81,17 @@ make all
|
|||
make flash
|
||||
```
|
||||
You would probably have to adapt the `UPLOAD_PORT` in the `Makefile` or set it via an environment variable.
|
||||
|
||||
|
||||
|
||||
## Battery Life
|
||||
The hardware was designed with two options to drop the battery voltage to a level, which can be fed to the ESP32: A voltage regulator or a simple diode.
|
||||
|
||||
A test with increased data rate (for a shorter test duration) showed, that the voltage regulator leads to a slight battery life benefit.
|
||||
Using a measurement interval of 30 seconds and a WiFi connection interval of 3 minutes, the 2500mAh LiIon (3.7V) battery lasted 30 days with the diode and 36 days using the voltage regulator.
|
||||
|
||||
The selected voltage regulator has a quite low drop-out voltage and more importantly a low leaking current during the deep-sleep phases, which have a very low current needed by the ESP32.
|
||||
In comparison a diode has no leaking current at all, but a more or less fixed voltage drop.
|
||||
|
||||
The benefit of the voltage regulator is, that the battery voltage range can be exploited further than what can be done with the diode.
|
||||
The lowest operational battery level was 3.2 V using the diode and 2.8 V using the voltage regulator.
|
||||
|
|
Loading…
Reference in a new issue