Use LS7232 to create a touch-sensitive dimming light

The touch-type dimming light circuit made with LS7232 ASIC is shown in Figure 2-16. This circuit has two
touch electrode pads, Ml is an ordinary dimming touch pad, and M2 is an automatic dimming touch pad. When the light is on, just
touch M2, and the light will gradually dim until it goes out.
    The circuit on the left side of the dotted line is basically the same as the circuit on the left side of the previous section and will not be repeated here. The difference is the application of the pin 2
function of LS7232. The automatic dimming circuit is mainly composed of NAND gate A2 (CD4093) with Schmitt input characteristics. NAND gates
I and II form an RS-FF circuit. When a low level the RS-FF is reset. When a low level appears on the M2 terminal,
the RS-FF is set (Q = "H"). The NAND gate m forms a controllable oscillator, and its oscillation frequency is determined by R7 and c8. When Q = "ear'
level, the oscillator starts to vibrate. When Q = "L'' low level, the oscillator stops vibrating. C6 and C7 are used to eliminate spike interference , and R5
has the same function as R3. When you touch M2 with your finger, the Q point is high level "H", the NAND gate ni starts to oscillate, and the oscillation pulse is added to
the 2-pin CK terminal of LS7232. Each time a down pulse is input to the CK terminal, the output terminal Io is triggered. When the pulse lags behind a certain phase angle, the light becomes
a little darker, and then it automatically gradually dims until the minimum brightness (conduction angle 350) turns off the light. Or during the dimming process,
if your finger touches M1 to reset RS-FF (Q-''L"), the light will maintain this brightness. Of course, if the hand touches M1
for more than 0.399s, the light will The function of the dimming function is the function of pins 5 and 6 of A1. Touch Ml again to turn off
the light.