PlantCare Best DIY Present for Mothers

by Rundhall in Circuits > Arduino

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PlantCare Best DIY Present for Mothers

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Hello everyone,

This is an instruction, how I built the perfect present for my mother. The project is a multifunctional, automatic plant watering device.

Features of the device:

  • measures and shows the actual soil moisture level of the plant
  • if the soil moisture level is lower as the threshold, it turns on a pump to water the plants.
  • the user can change the threshold with a button, and see the actual threshold on LED-s.
  • The threshold is stored in non-volatile (EEPROM) memory, after turning off the device the customised threshold will not be lost.
  • the device is working on one 18650 Li-Ion batteries for weeks.
  • the device has a built-in charger, the battery can be charged with a usual phone adapter.
  • as a secondary usage, the device can be used as a 3.7 V 18650 Li-Ion battery charger if there are no plants to care for.
  • if the water tank is empty the device turns off the pump and saves battery and the pump lifetime as well. However, it turns the pump regularly on for a short time to check if the water is refilled.

How to Use

PlantCare Best DIY present for mothers
  • prepare a water tank
  • put the pump into to water
  • push the moisture sensor into the soil
  • turn on the device with the switch
  • the measured value is shown every 8 seconds
  • plug a phone adapter to charge the battery
  • without crochet, it is a battery charger
  • press the button to set the threshold
  • if watering does not change measured value, it turns on pump only for a short time, this will save battery and lifetime of the pump

BOM List

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Materials needed for this project. BOM list:

Total material cost of the project: 8,34 $/total project

Tools

The following tools are needed:

Total tools cost of the project: 116,36 $/total project

Circuit

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Major components:

  • Soil moisture sensor: analog output, which will be an A/D reads at microcontroller, usual between 0 and 500 digits.
  • Button, input at PIN 9, pulled to GND by an external 10 kohm resistor, another button PIN is connected to PIN10 which is pulled up to VDC by an internal resistor. If it is pressed it will change the threshold and will show on LED-s.
  • LED-s, 3 pcs external LEDs and 1 pc onboard LED. During operation it shows the actual readouts from moisture sensor 0-100 = all LEDs off, 100-200 = 1 LED on, 200-300 = 2 LEDs on, 300-400 = 3 LED-is on, 400 or bigger =4 LEDs on.
  • Water pump, it switches on/off by an N-Type MOSFET, which is controlled by the 10th PIN of Arduino. LOW = pump off, HIGH= pump on.
  • Switch, it decides if the device is in turned on/off mode or in charging mode
  • Battery with a holder
  • Battery charger

Take all component and connect them according to the schematic. Use a DIY Prototype PCB and solder everything, use wires to connect PIN-s. The moisture sensor should be soldered to the back of the Arduino board to save space.

Software

Connect the Arduino board to a PC. Use Arduino IDE to compile an upload the program to the Arduino. The code is full of comments.See attached.

Downloads

Automatic_plant_watering_unit.ino

Housing

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Create a housing to protect electronics to be damaged by touching. The housing can be a 3D printed or small plastic boxes. This device has a handmade crochet holder.

I used my crochet for gadget Android application to create a housing for the device. It helps to create crochet housing for any type of rectangular PCB. The link to the application:

https://play.google.com/store/apps/details?id=com....

The application is free with some restriction. Please buy the full version of 1$ to support my instructions.

End Words

This project is still under testing. The measured consumption: 60uA. I expect to have months without recharging. The challenging part is to have fresh water in the water tank. I will install a buzzer to make some noise if the water tank is empty.

Have a nice day!