Problem 1

• Choose title

• 1st XML

• 2nd electronic spider

• 3rd infrared remote home control

• Waste time

Problem 2

• Write Program

• Added Delay subroutine

• Added Table Loop

• Delay execution time

• Not necessary

Test ResultInput (dual-tone signal) Output (89C51 port1 LEDs) pin8 to pin1

0 0 0 0 0 1 1 1 1

1 0 0 0 0 0 0 1 0

2 0 0 0 0 0 1 0 0

3 0 0 0 0 1 0 0 0

4 0 0 0 1 0 0 0 0

5 0 0 1 0 0 0 0 0

6 0 1 0 0 0 0 0 0

7 1 0 0 0 0 0 0 0

8 1 1 1 1 1 1 1 1

9 0 0 0 0 0 0 0 0

0 0 0 0 0 1 1 1 10-off

1-on

Problem 3

• LEDs unstable

• Use resistor connect 5V

• Pulled the LEDs HIGH

• LEDs become stable

Problem 4

• Remove Reset button

• Cannot receive input signal properly

• Added the Reset button in 89C51 pin 9

• 89C51 receive signal before pressed Reset button

Problem 5

• Test success in the breadboard

• Tried to connect to the board

• Telephone’s current breaks down the 89C51

• Added a relay counter

• Hold the input current

Problem 6

• MT8870 does not auto hook off on telephone

• Connect to 4040 & RY6WFZ-K relay to MT8870

• Ringing value at 2 to power 12

• Can auto hook off the phone

Problem 7

• Voltage of ringing signal between +1.4V to –1.4V

• Unstable & Not enough power

• Connect 4040 with amplifier & transistor

• Pulled HIGH the voltage

• Rectified the current

Problem 8

• Dual tone receive signals– Full wave rectified

• 4040 counter only accept – Half wave rectified

• Added a diode to transfer

• Signal become half wave rectified

Problem 9

• Signal’s current too high

• 4040 Counter break down

• Change the 4040 counter

• Added a relay to prevent

Test Result

• Phone in Phone 4040 counter auto hook off Key pressed Dual tone MT8870 Binary code 89C51 LEDs Display the result

MT8870 & 89C51 scematic

MT8870 & 89C51 breadboard

Relay & 4040 counter schematic

4040 counter & relay breadboard

Power supply schematic

Power supply board