Night door lock automatic light circuit

At night, it is dark in front of Xiu Mi's door from the outside, and it is very inconvenient to lock it. Here is an introduction to a white-activated light.
When you turn the key to r J aii, the small light in front of the door will automatically light up, and the f J light inside the door will also turn off at the same time. At this time, you
can easily complete the opening action. After 20 seconds, the door light will automatically turn off. The circuit of the automatic light is shown in Figure 233.
    The gate tube VT4 and the diode tubes VDl - VD4 form the main circuit of the control circuit. Control ll It is composed of Lunan touch circuit
, Bidig circuit and delay circuit. Normally, the transistors VT1 and VT2 are in the cut-off state,
the KD-9300 music doorbell chip does not work, VT3 is cut-off, and the VT/l field has no trigger current. Ding Qiang is in off state, and the small lights
Fl and E2 are not on.
    M is the touch electrode connected to the metal door lock. When the key touches r, the lock M buzzes. The miscellaneous signal induced by the human body passes
through R, and is injected into the v¨ rI base. Make VT1 turn on quickly, Vl. also turns on. The music integrated circuit
works because the trigger terminal TRIC; obtains a positive pulse trigger voltage, (), and the P terminal outputs a music
signal , fresh VT3 Amplify ~ R, C, smooth, and move to the f J pole of VT4, so that the lights F, l, and E2 of VT4 will
light up and call. After unlocking, the human body is de-energized, and although VT1 and VT2 return to the cut-off state, However
, once the music integration block is triggered, it can still maintain the output until the end of a piece of music, which is iL. After 20s, as the music piece is completed,
the integration block returns to the static state, VI 4 loses the trigger current, and when the AC lU crosses zero That is, the light E1 and F2 go out
. The photoresistor RI and the tube tube W1, 2 form a light control circuit, which blocks the circuit during the day and
can only be triggered to work at night, and
    the music integration [U The circuit should use the KD-9301) doorbell chip with built-in music K in about 20 seconds. VT1 and
VT2 use 901 4-type silicon NI, N diodes, requiring p ≥ 200; VT3 can use 9013-type silicon NPN) diodes
, p ≥100. VT4 can use 2N656:1 type micro-triggered unidirectional thyristor, and its maximum load current is 0 SA.
VS uses 3v, ], +2W Zener diode, such as I'Z 3 6R type, etc. El, F2 can be used
For the 15W small incandescent
bulb used in the refrigerator , E1 is placed just outside f J, and F_2 is installed inside the door. In this way, when the door lock is touched or the key touches the door lock, E1 lights up and the keyhole can be seen clearly. The lock will be unlocked by force, and the E2 light can be used to turn on the lights or do other
things after entering the door. R. and R are two high-impedance resistors respectively to ensure the safety of the piece J. It should be noted that the door lock
must be grounded The insulation is good, otherwise the small circuit will prevent normal operation. Some families install r anti-theft metal doors, and the f J lock and
the metal door have become a whole. At this time, M cannot be connected with the door lock . At this time, the following methods can be adopted: Find an organic
On the glass or plastic plate, drill 1-n and m small ties in the center of f, and pass the plastic wire through the small hole. Weld a
piece of omni-moulded U milling piece to one end of the wire, then tighten the wire and use epoxy resin to seal the wire Glue the piece firmly to the plastic plate (h)
and connect the wires to the resistor R. Then fix the plastic plate at the appropriate position outside the door. When I go home at night, I will touch
the tinplate piece of the plastic plate and the door light will be on. Lit up.