Smart Pot Arduino

This repository contains the source code for the Arduino firmware that powers the Smart Pot. In this document the installation of the firmware on the microcontroller as well as the construction of the circuit are described. This guide does not cover the construction of the actual pot or how to integrate and waterproof the electronics.

Setup

Hardware Requirements

To build your own Smart Pot you need the following components.

• An Arduino Nano 33 BLE.
• Two capacitive soil moisture sensors. One of which is used to measure the soil moisture and the other to monitor the water level of the water tank.
• A water pump and a compatible relay. We recommend to use a peristaltic pump. They are slower but more precise and don't have to be submerged under water.
• A DC power supply and matching power plug. Make sure that your power supply can deliver enough power to drive all other components simultaneously. Ideally the voltage of the power supply matches the rating of the pump. The Arduino Nano 33 BLE can accept an input voltage of at most 21V.

Since the Arduino Nano 33 BLE uses 3.3V, the sensors and the relay must be rated for a voltage of 3.3V as well.

Wiring

Connect the components to the microcontroller as follows.

Component	Pin
Soil moisture sensor	Analog pin A0
Water level meter	Analog pin A1
Pump relay	Digital pin D2
DC power plug	VIN and GND

Remember to connect all components to GND and VCC according to their datasheets and connect the pump via the relay to the DC input voltage in the normally open position.

Dependencies

The firmware uses the ArduinoBLE library. The correct version of the library is included with this repository as a Git submodule. Use the following commands after cloning this repository to initialize and download the library.

git submodule init
git submodule update

Firmware Installation

To install the firmware on your Arduino, proceed as follows.

• Open the smart-pot sketch in the Arduino IDE.
• Install Arduino Mbed OS Nano Boards under Tools > Board > Boards Manager.
• Connect the Arduino with your PC via USB.
• Select the correct COM port under Tools > Port.
• Select Ardunino Nano 33 BLE under Tools > Board > Arduino Mbed OS Nano Boards.
• Click the Upload button and wait for the firmware to be flashed.

Note: Before installing the firmware you may have to tweak the constants at the top of smart-pot.ino to match your setup. For example, adjust FLOW_PER_MINUTE if your pump does not deliver the configured value of 150 milliliters per minute.

License

The Smart Pot Arduino firmware is licensed under the MIT license agreement. See the LICENSE file for details.