🌱💧 An open source DIY soil moisture sensor

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Jan-Henrik Bruhn 905978e8c9 Only read positive voltages in adc.c The ADC sometimes responds with negative voltages read on the ADC input due to noise. This can lead to very high illuminance readings at night (4095 << 4 to be exact due to two's complement :) ). This commit caps ADC readings at 0.		2024-02-14 11:59:14 +01:00
.devcontainer	Update to nRF Connect SDK 2.5	2023-11-07 18:31:32 +01:00
.github	Update to nRF Connect SDK 2.5	2023-11-07 18:31:32 +01:00
bridge	Defaults to BLE protocol version 1	2022-03-15 08:52:37 +01:00
case	Replace Current High Airflow Cases	2023-07-02 11:33:26 -05:00
code	Only read positive voltages in adc.c	2024-02-14 11:59:14 +01:00
data/adc-moisture-estimation	Sets transmitting power to +8dB	2021-03-31 18:37:50 +02:00
experimental/rotisserie	Adds missing base.stl to experimental/rotisserie	2022-11-08 19:19:08 +01:00
flashing/pyocd	Fixed typo in readme and changed meaning of the sentence to better reflect the actual situation.	2022-10-23 19:00:57 +02:00
img	Update README.md with photo of v2.0.0 board	2023-03-30 19:20:33 +02:00
kicad	Update date on pcbnew	2023-03-19 15:06:39 +01:00
.gitignore	Adds a simple battery monitoring circuit and analog to digital measuring.	2021-02-14 10:59:18 +01:00
CODE_OF_CONDUCT.md	Create CODE_OF_CONDUCT.md	2023-06-09 09:27:46 +02:00
kitspace.yaml	Update kitspace.yaml	2023-05-08 08:58:08 +02:00
README.md	Fix broken link for ALS-PT19 datasheet	2024-01-01 23:02:42 +11:00

b-parasite

PCB front and back photo

b-parasite is an open source soil moisture and ambient temperature/humidity/light sensor.

Features

Capacitive Soil moisture sensor - see this blog post, this Twitter thread, and this post for nice resources on how they work
Air temperature and humidity sensor using a Sensirion's SHTC3
Light sensor using an ALS-PT19 phototransistor
Powered by a common CR2032 coin cell, potentially for over two years
Support for nRF52840 and nRF52833 modules
Open hardware and open source design

This repository also hosts a few different firmware samples for b-parasite.

Sample	Description	Extra Documentation
samples/ble	This is the most battle-tested and useful firmware. It periodically reads all sensors and broadcast them via Bluetooth Low Energy (BLE). It works with Home Assistant + BTHome out of the box.	Docs
samples/zigbee	An experimental/educational/exploratory basic Zigbee sample built on nRF Connect + ZBOSS. It integrates with Home Assistant via ZHA or Zigbee2MQTT.	Docs
samples/blinky	The classic "Hello, world"	-
samples/soil_read_loop	Reads the soil moisture sensor on a loop. Useful for experimenting and calibrating the sensor.	-
samples/input	Handles button presses. Useful for power profiling GPIO interrupts and testing debouncing for push switches on boards that have them.	-

Information about how to order, assemble, build the samples, protect the sensor and flash the firmware is on the Wiki.

code/nrf-connect/ - Common library and samples, built with Nordic's nRF Connect SDK.
kicad/ - KiCad schematic, layout and fabrication files for the printed circuit board (PCB)
data/ - data for testing and sensor calibration
bridge/ - an ESPHome-based BLE-MQTT bridge
case/ - a 3D printable case

b-parasite stuck into a small plant vase

Render of the original 3D printable case

We have three different 3D-printable cases:

The hardware and associated design files are released under the Creative Commons CC BY-SA 4.0 license. The code is released under the MIT license.