This small box accepted the command passed by a phone call to control multiple home appliances. Designed hardware based on AT89C251 (8051 family); developed the program with Franklin C-51 and ASM-51.
Using predefined dialing sequence to determine if the call was intentional to the controller. After the phone line was picked up by the controller, the user should input PIN to verify user's identity. Then the user might key in the commands by phone to switch or check the on/off status of the appliances.
Addtional Information:
- Phone line => Bridge (Full Wave Diode Bridge) => DTMF (Dual-Tome MultiFrequency) decoder/encoder => AT89C251
- AT89C251 => transistor switch to connect phone line
- AT89C251 => transistors to drive relays for switching on/off the appliances.
