It's an intelligent office door opener system, which opens the door when you press the button on the intercom, developed following the request of a customer.
Normally, to achieve this result the ring tone and the door opener are connected along, inside the office, using a relay.
This advanced door opener, however, simulates the presence of a person that manually opens the lock: waits for a time all the times different from the pressure of the button, and equally eventually presses the opening for a number of times, interspersed between with their different times.
The hardware choice for this device is obviously a microcontroller, appropriately programmed and equipped with a some galvanically isolated inputs and outputs .
I used for the prototyp the popular Arduino, in the ONE version. However, to write the firmware I used Atmel Studio 7.0, without the use of the libraries Arduino and its bootloader.
This choice is motivated by the decision not to disclose the source of the firmware.
Future embodiments will be based on a printed circuit board specially designed for the purpose.
An interesting subsequent development of this intelligent door opener will be the possibility of recognizing a code to effect opening.
In practice, by pressing the call button with a predefined sequence, you can associate the opening of a secret code that is known only by the owner.