Arduino used as an interface between an old rotary dial telephone and a cellphone
- Arduino
- Opto-Isolators (13)
- 1k Resistors (13)
- 10k Resistors (2)
- An old rotary dial telephone
- A cheap cellphone
- wires
Is diagram is only an example for connecting the cellphone keypad to the Arduino (on the left)
The blue wire connects to a row on the keypad and the green, to a column.
To do the whole keypad, you'll need to connect each O-I to its combination of row and column.
3.3v is enough to power the dial since in essence, it's just a switch (disappointing.. I know.. I thought that'd be way more fancy :) The grey wire serves to detect when the dial is in use. The orange wire goes the the output of the dial's pulsating switch