Device, scheme of which is shown, includes coverage on the landing when opening any of facing her door and turns off its after a certain period of time after the doors are closed. In the initial state of all contacts mounted on the door frames of reed switches SF1-SFn closed under the action of the close of permanent magnets, fortified on the doors. As a result, the logical level at the exit of the element DD1.2 - low. The capacitor C3 is charged to the supply voltage, so low level is present at the exit of the element DD1.4. The VT1 transistor and SCR VS1 closed lighting lamp EL1 is not lit.
If you open the door, the contacts mounted on its frame reed switch will be are open, and the capacitor C2 is charged through the resistor R2. Low the exit of the element DD1.2 changes to high, that will lead to the discharge of the capacitor C3 through the diode VD3, the resistor R3 and the output circuit of the element DD1.2. Output level element DD1.4, in turn, will become high, which will lead to the opening transistor VT1, SCR VS1 and switching the lamp EL1.
When the door closes and the level at the exit of the element DD1.2 will again become low, lamp EL1 some time until the capacitor C3 is charged through the resistor R4, will remain enabled. When specified on the circuit component values it takes approximately 20 seconds, after which the device will return to its original state and lamp EL1 goes off.
Diode bridge VD1 necessary that the current through the SCR VS1 flowed in only one direction. Chain R1C1VD2 - node power-DD1 chip.
Chips instead of CLA you can install CLE.
Conclusions many of reed switches (including CAM-1, CAM-2) are not designed for soldering So the stripped insulation from the ends of the connecting wires on them just wind, locking segments of PVC tubing. Required to manage the reed switches of the permanent magnets can be removed, for example, from magnetic door latches.
Instead of the reed switches is possible to use other sensors, for example, microswitches PM-1T, PM-2T, MP1, MP3, MP5, MP, setting them so a way that the contact is closed when closed and opens when opening doors.
Author: V. Polovinkin, Zheleznogorsk, Kursk region