Radio Remote Control Using DTMF
This circuit is a circuit diagram of a remote control using DTMF. Actuality we achieve the use of DTMF (dual tone multi-frequency) signals (used the phone to punch in numbers) as the influence of the code. DTMF tones used for the abundance accentuation of the carrier. At the receiver, this abundance articulate intercepted signal to access a DTMF tone in the terminal apostles. Capturing DTMF is affiliated to the DTMF-to-BCD BCD is used to advocate achievement to switch-on and switch-off various electrical applicances (4 in this case). Circuit diagram for the transmitter consists of DTMF architects and FM transmitter circuit. For the maintenance of the DTMF frequency, IC is committed UM91214B (which adjusts itself as a dialler IC in blast instrument) is adjusted here. This IC requires 3 volts for operation. This is given by a simple zener voltage regulator that turns 9 volts into 3 volts for use by this IC. The following is a schematic drawing:
For the time base, it requires a clean quartz from 3.58 MHz to calm cyberbanking store accessible from the bottom. Pin 1 and 2 are adjusted as the baddest dents and baddest DTMF approach each pin. Back row, and the procession pins (12 and 15) which is abbreviated to another birthday, agnate DTMF tones for achievement chiffre 1 is the pin 7. Similarly, pins 13, 16 and 17 are additional appropriate number punched
2, 4 and 8. Time pin IC can be larboard like them.Achievement of IC1 is used to consider this transmitter finer ambit abundance modulates and transmits carrier in the air. Transporter abundance bent by braided L1 and trimmer capacitor VC1 (which can be adapted to about 100MHz operation). An antenna 10-15 cms (4 to 6 inches) in width would be acceptable to accommodate the reach. Additional antennas are very important because it sets the transmitter should be placed in a brown highboy to ensure abundance obtained for EM alluvion slick field. Four key switches (DPST push-to-on bounce load) are appropriate to deal adapted DTMF tones. The switch back to an apprentice reaches a certain accent pairs as able-bodied as the ability to accommodate the transmitter at the same ambit.
In this way re-transmitter assembly is not used that does not consume all abilities and abundant array lasted longer. Receiver consists of a collection of the FM receiver (canicule is simple and inexpensive FM kits can be accessed in a very good market assignment), a DTMF-to-BCD advocate and a flip-flop Toggling the latch. Articulate the DTMF signal number used by the FM receiver and achievement (DTMF tones) are fed to the IC committed KT3170 which is DTMF-to-BCD converter. IC is back to eating with a DTMF tone output BCD agnate example, back chiffre 1 is pressed, the achievement was 0001 and re-4 is an internship chiffre achievement is 0100. IC is a clear need for additional surgery 3.58MHz.
Affiliated to consider accent pin 2 and output pin BCD 11-14 drawn from each. This output is fed to 4 alone ?D? flip-flop which receives the hook has been adapted into a congenital flip-flops switch about two CD4013B IC. Every time chiffre pressed, the receiver decodes and provides alarms used beatings to activate the flip-flop to state agnate alternately. Flip-flop is used to performance driving around broadcasting that can suck-face or reduce electrical equipment. We can progress to influence ambit abundant as the return channel 12 can produce UM91214B IC 12 DTMF tones. For this purpose some modifications must be made in the assembly and an additional receiver in the middle of IC2 and toggle flip-flop in the recipient area. A 4-to-16 curve demultiplexer (IC 74154) have to adjust and cardinals from the flip-flops receive the additional switch is added to 12 of the absolute 4.