DIY Wireless Automatic Plant Watering System Without Internet Access Requirement

I'd like to automatically water my plants regularly, perhaps once or twice a day depending on different seasons. But instead of getting an IOT buddy to do the job, I'd prefer something stand alone for this specific task. Because I don't want to go through the hassle of registering and downloading an extra app on my phone, nor keep everything stay online, just to change the watering interval settings for a total of 3 or 4 times per year. A solid easy access timing unit who doesn't rely on other system and work behind scenes is all I need.

ESP8266 module can not only work as an internet client, but also a standalone AP who serves web pages, which means I can use this AP mode to remotely set the watering time by accessing a preconfigured web page within it's local network range. So comparing with traditional timer units, with the ESP8266 server, I don't need to physically having access to the unit to change the time setting, on the other side, comparing with other IOT units, it doesn't require an internet access to perform it's daily routine.

Step 1: What You Need?

This is project requires very few basic items. If you have some arduino background, it will be a little piece of cake for you.

Items needed:

Hardware:

WEMOS D1 R2 Module
1 Channel Relay Module
DS1307 RTC module
ABS Plastic Junction Box
DC Connectors
12VDC Electric Solenoid Water Valve 1/2"

Software:

Arduino IDE

Step 2: Wire Things Up!

Connect everything according to the diagram. It's pretty straight foward. The only little tweak is that I soldered another DC connector to the wemos board, so it's easier for me to fits everything in the box.

Few other thoughts:

The reason I chose WEMOS D1 R2 over other popular esp8266 modules is because we're going to use 12V DC input voltage.While most ESP8266/32 modules work between 3.3v to 5v input range, this module's on board regulator can handle the 12V DC input natively. That means a single 12v dc war charger can power the entire group without needing an extra 12 to 3.3 or 5v step down regulator.However, if you prefer to work with other ESP module you surely can, just change few pins in the code and you are good to go.