I am try to add a solar panel and rain drop detector.

Well here what Arduino part I found:

2PC 5V Micro USB 1A 18650 Lithium Battery Charging Board Charger Module Arduino

5V 1.25W Mini Solar Panel Module DIY For Light Battery Cell Phone Charger Toys

https://www.ebay.co.uk/itm/253539736174

DIY Raindrop Sensor + HL-01 Module w/Jumper Wire For Arduino

https://www.ebay.co.uk/itm/232253476794

Nano V3.0 ATmega328P CH340G 5V 16M MINI USB Nano V3.0 Compatible to Arduino (may need to change if wrong)

DS18B20 Temperature Temp Sensor Waterproof Digital Thermal Probe 1M For Arduino

5V 1/2/4/8/16 Channel Relay Board Module Optocoupler LED for Arduino PIC ARMAVR

https://www.ebay.co.uk/itm/391953530998?var=660915496877

Details about Shield DHT11 sensore umidità temperatura modulo arduino humidity temp cavo 10009

https://www.ebay.co.uk/itm/182595895852

LDR Photoresistor Photo Resistor Light Detection Sensor Module Arduino PIC PI 5V

Hygrometer Humidity Detection Module Moisture Testing Sensor for Arduino Z8O5