The solar powering unit has a timer which turns on the Arduino in regular intervals. I do not have to keep the Arduino on all the time.The unit can also power the Arduino when there is no sunlight (at night) as it has a rechargeable battery inside.
My idea is to implement a device that turns a normal text into Braille alphabet. A camera scans and reads the text and with a raspberry pi these data are transferred to a machine that pierces a cardboard according to Braille alphabet so that a blind person can read the text.
This project idea uses fire and smoke sensors for the fire detection, the data are sent to an actuator that can decide what extinguishing substances it will be more useful and quickly to extinguish the fire and send an alarm on a phone.