Wireless Remote Circuit This introduces the circuit that utilizes RF signal remote control various electrical appliances, and the number of remote controls is 4 channels, and it can be expanded to 12 when needed. It uses the DTMF (Dual Solver) signal in the phone to modulate the 100MHz to modulate the 100MHz to send it. The receiving circuit is demodulated into a DTMF signal with a FM receiver, which is connected to the DTMF / BCD converter to convert to the BCD output for controlling the switching and shutdown of the 4-channel electrical appliance. Remote transmitter (see Figure 1) consists of a DTMF generator and a FM transmitter circuit.
Here is a circuit that utilizes RF signal remote control various electrical appliances. The number of remote controls is 4 channels, and can be expanded to 12 channels when needed. It uses the DTMF (Dual Solver) signal in the phone to modulate the 100MHz to modulate the 100MHz to send it. The receiving circuit is demodulated into a DTMF signal with a FM receiver, which is connected to the DTMF / BCD converter to convert to the BCD output for controlling the switching and shutdown of the 4-channel electrical appliance.
Remote transmitter (see Figure 1) consists of a DTMF generator and a FM transmitter circuit. Here, a UM91214B telephone dedicated IC is used to generate a DTMF signal, and its 3V supply voltage is supplied from the 9V battery through 3V Zener tube D1. The circuit uses 3.58 MHz crystal as a time-based circuit, IC1 {12}, {15}, respectively, the first row and the first row of foot, respectively, through the switch S1 (b) short-circuited, then {7} foot output DTMF Signal (sound) is equivalent to a dual-tone multi-frequency signal sent out by the telephone number 1. Similarly, {13}, {16}, {17} are second, second, third, third rows, {13} {15}, {13} {17}, {12} {16} When S2 (b), S3 (b), and S4 (b) are short-circuited, the signal of {7} foot output is equivalent to a dual-tone multi-frequency signal sent from the telephone number 2, 4 and 8. The remaining feet of IC1 is not used as it is.
The transmitter circuit consists of transistor T1 and its peripheral circuit, wherein the tuning circuits L1 and VC1 are tuning near the 100 MHz carrier frequency, the antenna has a whip antenna, a length of 10 cm to 15cm, and the control range is quite good. The DTMF signal feeds the base of T1 from the {7} foot of IC1, and then transmits outward from the antenna ANT.
The receiving portion (see Figure 2) consists of a DTMF / BCD transform chip IC2 and a set of four trigger latch circuits Ic3, IC4 of the FM receiver. The FM DTMF signal is first converted to a BCD signal with IC2 after demodulation of the FM receiver. At this time, the digital "1" is 0001, the digital "4" is 0100 ..., etc., IC2 also operates with 3.58 MHz crystals. The BCD signal is sent from {11} ~ {14} to 4 D trigger latches, which is provided by two dual D triggers (CD4013B), "1", "2", " 4 "," 8 "NETROUND When either switch, the clock input terminal corresponding to the number of the N-Trigand is sent, so that the output state of the D flip-flop is flipped, thereby driving the relevant Transistors and corresponding relays are sucked and release the action, thereby turning or shutting down or turned off the relay controlled electrical appliance.
Since the UM91214B can produce 12 DTMF signals, it is simply added a 4/16 line converter with the number of control buttons in the transmitter circuit and the IC2 and D flip-floping at the receiving portion, and the D flip-flop corresponding Increased to 12, the control of 12 electrical appliances can be controlled.
Our other product:
