Design of simple blind reporter

Probe domestic double-head probe 038-BB-5.7L The shape of the two ends of the needle is outside the pointed needle

Photocoupler

The main part of the circuit is the 555 timer. The 555 Timer is a mid-scale integrated device that combines analog and digital functions. Generally known as 555, which is made by bipolar process, it is called 7555 in CMOS process. In addition to single timer, there is a corresponding dual timer 556/7556.555. The power supply voltage range is wide, which can be 4.5V~ Operating at 16V, the 7555 can operate from 3 to 18V with an output drive current of approximately 200mA, so its output is compatible with TTL, CMOS or analog circuit levels.
This reporter can use the voice to remind the blind to be born, and to inform the blind about the weather.