Traditional Chinese Practical Kids waking up: Circuit Design, Parts List & Workshop Prototype Guide

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Remote control wake-up device for kidsChildren sleep soundly in the morning and cannot get up on time, so their parents often have to wake them up. To this end, this article introduces a device for waking up children, which can remotely wake up children from across the room. It is convenient and practical, and can also be used as a remote control doorbell.How it works:The device consists of two parts: a radio remote control transmitter and a radio receiving controller, with an operating distance greater than 20cm.The principle of the transmitter is shown in Figure 167-1. It is an oscillator composed of a gate circuit. Its output signal passes through the "NOT" gates F1, F2, R1, and BC (32768Hz) to form a self-excited multivibrator with a very stable frequency. After its output signal is shaped by a parallel shaper composed of the "NOT" gates F3, F4, F5, and F6, it is coupled by the capacitor C1 and input into a high-frequency constant-amplitude oscillation circuit composed of transistors VT, LC and other components for modulation. The modulated carrier wave with a frequency of approximately 120 to 200 MHz is radiated into the air through the printed antenna WB. alt="236.jpg (43501 bytes)">Figure 167-1The transmitter uses a 9V laminated battery, which consumes no power when not working. Press the power switch SB and the indicator LED will light up, indicating that the transmitter is working.The principle of the receiving control device is shown in Figure 167-2. It is composed of a super regenerative detection circuit, an amplifier circuit, a frequency selection circuit, a trigger circuit, a sound generator and an audio power amplifier. In the amplification and shaping circuit composed of transistor VT1 and LC components, if the signal frequency resonates with the crystal oscillator BC, its impedance is very low and can enter the transistor VT2 smoothly through B; if the signal frequency does not match (interference clutter), the BC shows extremely high impedance and is not allowed to be sent to VT2. After the signal sent to VT2 is amplified, it is shaped by the "NOT" gates F4 and F5 and then triggers the audio integrated circuit IC2. IC2 is a voice integrated circuit that can emit a bugle sound and "Good morning, get up soon". R8 and C9 form an integrating circuit whose purpose is to prevent false triggering of spurious interference waves. The audio signal output by IC2 is very weak and not enough to wake up a child, so the signal must be sent to the audio power amplifier composed of IC3 and other components for amplification to drive the speaker BL to emit a loud sound. If the child still cannot wake up once, parents can press the button of the transmitter multiple times until the child wakes up. If the sound is too loud, the power amplifier circuit can also be composed of one or two ordinary triodes. …

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