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DTMF-controlled Home Appliance Switcher

DTMF-controlled Home Appliance Switcher
DTMF-controlled Home Appliance Switcher
This circuit can be called using your mobile or a regular telephone set (with DTMF keys) and after passing some procedures, you can control DC-powered appliances installed in your home. Examples include the front door latch and the pump of a plant watering system.
You call the circuit and after three rings, it will answer your call and you will hear two little beeps.
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Materials

Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

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PCB

Component list

Resistors
R1 = 68k
R2,R4 = 1k
R3 = 330
R5 = 10k
R6 = 100k
R7 = 220k
R8-R15 = 220
Capacitors
C1,C2,C3,C5,C9-C12,C15 = 100nF
C4 = 2µF2 40V radial
C13 = 1000µF 40V radial
C14 = 100µF 40V radial
Semiconductors
B1,B2 = B480C1500 (80Vpiv, 1.5A)
D1-D8 = LED, low current, 3mm
D9 = zener diode 4V7 400mW
D10-D15 = 1N4001
T1 = BD139
IC1 = Atmega8-16PC, programmed, Elektor Shop #080037-41
IC2 = MT8870
IC3 = 7805
IC4 = ULN2004
Miscellaneous
RE1-RE6 = 12V coil, e.g.V23057
X1 = 3.5795MHz quartz crystal
K1,K2,K3 = 10-way boxheader
K4 = PCB terminal block, lead pitch 5mm
K5-K10 = PCB terminal block, lead pitch 7.5mm
K11 = RJ11 connector, PCB mount, Hirose TM5RE1-64 (Digikey # H11257-ND)
J1,J2 = 3-way SIL pinheader with jumper
PCB, ref. 080037-1 from www.thepcbshop.com

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