Relay integration

[MarkHaysHarris777]

   

Another option for you is the Gert-Board !

... named for its designer, Gert van Loo. Gert is a Raspberry PI engineer, and a brilliant and talented developer of hardware as well as software.

The Gertboard has the Atmel Atmega328p chip... the same chip that is on the Arduino.  it also has the ULN2803 driver, and also GPIO buffer chips.

...  the idea here is that you program the 328p to actually do the relay control (opening and closing the door) and you 'talk' to the 328p via serial uart from the PineA64 for high level commands. (of course you could use GPIO too, once the POR takes place).  But, again, you have some buffer between the unreliable GPIO states of the PineA64 (until POR) and the actual relay interface which is low-level controlled by the 328p.