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Move the blinds up and down

Design principles

Control the blind motors
React immediately on the two buttons
The relais shall be connected in a fail-proof way: in series. The first relais switches the motor on or off, the second relais chooses which motor runs.
No need for interrupts and sleep mode (since we are mains powered and for simplicity). Hence we can also be repeater.
There are two mechanical buttons combined in 3 stable positions: up, down or idle. These are mounted on the wall next to the blinds.
No remote controlled movements while the buttons are in up or down state, only when idle.
If a motor runs, then after a timeout, the relais shall fall off. Measurement revealed that timeout of 20s was not sufficient to move the blinds completely up - so the timeout is set to 30s.
If a motor is running thanks to a remote command, changing one of the switch positions by hand shall stop the motor immediately for safety of operation (not yet implemented).
If a motor has been running and then stopped, you can not start it again unless a few seconds (4) later. This to prevent damaging the relais. This happened to me with the first implementation.
The software should protect the relais contacts from burning in or fusing by preventing to be switched on multiple times too short after each other.

Protect the relays against surges due to the inductive load with a varistor.
Protect the relays against surges due to the inductive load by prohibiting manual operation during a short period (1s?) after switching the motor off.
Measure current to be safe (not implemented yet)
AC current measurement can be done in software, since no accuracy is needed (not implemented yet)
Current sensor: CurrentSensor5A
If the buttons are pressed, the relais shall switch on and the motor runs. After a while, the motor current drops to zero, and the relais shall switch off (so that it does not keep drawing power). (not implemented yet)
If the motor current does not drop to zero after a timeout, the relais shall still fall off after the timeout.

State	Constraints	Description
idle		the motor is not running
button up	after 30s: trigger timeout	the motor is going up thanks to pressing a button
button down	after 30s: trigger timeout	the motor is going down thanks to pressing a button
wait	after 4s: trigger toggleTimeout	delay to prevent damage to the relais the motors should not be stopped and started too fast too many times - this burns out the relais contacts
remote up		the motor is going up thanks to a remote command
remote down		the motor is going down thanks to a remote command
up		the blinds are completely up
down		the blinds are completely down
unknown		the motor is not running we do not know what the position of the blinds is

Action	Validations	Description
buttonPressedUp	not state up	the up button is depressed
buttonPressedDown	not state down	the down button is depressed
buttonReleasedUp		the up button is released
buttonReleasedDown		the down button is released
timeout		after a minute, we give up
remoteUp	not state up no buttons pressed	a command has been received from remote for up
remoteDown	not state down no buttons pressed	a command has been received from remote for down
interrupt		while moving automatically, someone presses a button this serves as an emergency stop
remoteStop		while moving automatically, a remote STOP command is given this serves as an emergency stop
toggleTimeout		after a few seconds, it is safe to start a next action

MISO = M1 MOSI = M0

Component	Pin	Wire	Pin	Component
NRF24L01+ Adapter	VCC	red	5V	PowerSupply HLK-PM01
NRF24L01+ Adapter	GND	black	GND	PowerSupply HLK-PM01
NRF24L01+ Adapter	CE	white	D9	ArduinoNano5V
NRF24L01+ Adapter	CSN	orange	D10	ArduinoNano5V
NRF24L01+ Adapter	SCK	grey	D13	ArduinoNano5V
NRF24L01+ Adapter	M0 (MOSI)	yellow	D11	ArduinoNano5V
NRF24L01+ Adapter	M1 (MISO)	purple	D12	ArduinoNano5V
ArduinoNano5V	5V	red	5V	PowerSupply HLK-PM01
ArduinoNano5V	GND	black	GND	PowerSupply HLK-PM01
RelayModule2Channel	5V	red	5V	PowerSupply HLK-PM01
RelayModule2Channel	GND	black	GND	PowerSupply HLK-PM01
RelayModule2Channel	In1	green	D7	ArduinoNano5V
RelayModule2Channel	In2	blue	D8	ArduinoNano5V
Button 1		orange	D2	ArduinoNano5V
Button 2		purple	D3	ArduinoNano5V