Electronic Project Description



Remote Controlled Smart House


To control switchboard and devices in the house through digital Keypad,
RF Remote and Telephone.


The circuit consists of CM8870 DTMF to BCD converter, BCD to decimal converters,
UM91214 series telephone dialer IC, JK Flipflop and Relay Drivers.

The main circuit is built on a glass epoxy PCB and was custom made from Kits and Spares.
The FlipFlop and relay driver board is made from home designed PCB using conventional
process. Remote Commander was also made in home using conventional PCB designing methods.

The circuit works by taking DTMF(Dual Tone Multi Frequency) input tones(audio frequency range)
and device such as onboard IC, Base terminal of a cordless- Telephone or a FM receiver tuned
to a specific frequency.
DTMF is the telephone switching tones used for number dialing.
I used a cordless telephone unit to to send the tones which are then tapped from the
base terminal and a impidence matching circuit to feed it to the control circuit.
The control circuit uses CM8870 DTMF to BCD converter IC to convert the tones(digits)
to BCD and feed it to the Decimal converter which then signals the flip flops to
switch relays.
A FM Transmitter Remote commander was made as alternate.
After pressing a digit at the cordless phone Line 2, it switched ON or OFF devices.
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