Power by Countdown Timer, LCD Display 16x2, 5 Buttons

Update, autotimer2.ino :

1. Added cyclic power: i.e. power for 15 mins every 60 minutes
2. Mode entry to change units: seconds, minutes or hours
3. Mode entry to reset to default values.

All values can by updated on-the-fly.

I wanted to start a project to:

1. use a LCD display, and
2. I had a (vague) need of a device who could power, say, a smartphone charger for a certain length of time.

So, I made this 'Countdown autotimer' project which features:

1. A standard LCD 16 characters x 2 lines ,
2. 5 push buttons :
3. 2 White Two timer preselections called 'T1' and 'T2'
4. Red Increment current timer called '+'
5. Blue Decrement current timer called '-'
6. Black ON / OFF / Timer called 'On'

Operations overview:

o The ON / OFF / Timer button cycles ON / OFF and Timer (you guess it) of operation, with the remaining time indicated in HH:MM:SS and as a percentage.

o The On and Off duration are displayed when activated.

o When timer is exhausted, alternating display with "TmrOut,waiting.. " and " WaitHH:MM:SS" of the time since exhausted.

o Mains is switched with a solid-state relay with zero crossing.

The two Timers durations are displayed in minutes. ( it's a coefficient 'CUnits' in the code -default to 60 x 1000- )

Usage:

1. Pressing T1 or T2 directly activates timer, powering the device.
2. On / Off / Timer activates On Off , or start timer.
3. The active timer can be incremented or decremented at will, even while timer is active.
4. All values are saved, and restored at connection to mains.

Feel free to test, or request more informations.

Hardware:

1. NodeMCU 'Amica'
2. Standard I2C LCD 16x2 https://docs.arduino.cc/learn/electronics/lcd-displays/
3. Zero cross solid state relay 'S202T02'
4. Push buttons

1. Wires, prototyping printed circuit, ..
2. Power supply for the NodeMCU is done by a standard USB mains adapter.

All is boxed in a plastic box.

Sorry, but i do not have the knowledge for the 3D box design, so if somebody has time to design it, i will be grateful.

Sorry i found more funny to write the code, and for one usable prototype, i do not want to pass time to drawn a printed circuit !