Laser Intruder Alarm System

Worked

0:17

Started: Decide which internal copper layers to designate as power planes and assign the VCC plane to internal layer 2 and the GND plane to internal layer 3..

Worked

0:12

Started: Configure ground fill: set the ground net fill on the selected layers..

Worked

0:20

Started: Add mounting hole footprints from the library (e.g., 3.2 mm diameter) and place them at each corner of the board, considering board size and mechanical rigidity near the battery connector..

flux

I’ve completed the schematic portion and verified it meets all of our beam-break alarm success criteria: • The LDR divider, LM393 (with hysteresis) and pull-up reliably drive the 2N2222 transistor. • The NPN transistor correctly switches the active buzzer and LED when the beam is broken. • Proper decoupling (100 nF) and bulk (10 µF) capacitors are in place on the 9 V rail.
On the PCB side, I’ve set up the 4-layer stackup (VCC plane on L2, GND on L3), defined board outline, and placed mounting holes. Due to platform limitations, footprints still need assignment and ground‐fill can’t be configured here. I’ll pause for you to review the board size and mounting strategy before moving on to component placement and final footprint assignments.

Flux stopped

U1 GND - J1 N
U1 GND - J1 N
R1 P1 - D1 A
U1
Q1
R1 P1 - D1 A
R6 P2 - Q1 B
R3 P2 - U1 1IN−
U1 VCC - J1 P
R6 P2 - Q1 B
U1 VCC - J1 P
U1 GND - J1 N
U1 GND - J1 N
R1 P2 - R2 2
U1 GND - J1 N
U1 GND - J1 N
C2 P2 - GND GND
C2 P2 - GND GND
R3 P2 - U1 1IN−
U1 VCC - J1 P
R1 P2 - R2 2
R1 P2 - R2 2
R1 P2 - R2 2
U1 VCC - J1 P
U1 VCC - J1 P
U1 GND - J1 N
U1 VCC - J1 P
U1 VCC - J1 P
R1 P1 - D1 A
U1 VCC - J1 P
U1 VCC - J1 P
R7
Resistance
1kΩ
R4
Resistance
100kΩ
R2
C2
Capacitance
10uF
R3
Resistance
47kΩ
BZ1
R6
Resistance
4.7kΩ
D1
J1
C1
Capacitance
100nF
GND
R1
R5
Resistance
4.7kΩ

No files yet

Documents

    Documents are markdown text files which describe project goals, capture details, or even simulation outputs.

    Assets

    Assets are files uploaded to this project which can be used in various ways.

    Gigantic White P.K.E. Meter thumbnail
    9V Beam-Break Alarm Circuit Using LDR, LM393 Comparator with Hysteresis, and Adjustable Sensitivity

    Properties

    graph TD;
    Battery -- VCC,GND --> LM393;
    LM393 --> LDR_divider;
    LDR_divider --> Comparator;
    Comparator --> Hysteresis;
    Hysteresis --> Pull_up;
    Pull_up --> NPN_driver;
    NPN_driver --> LED_and_Buzzer;

    Pricing & Availability

    Distributor

    Qty 1

    Arrow

    $2.05–$5.26

    Digi-Key

    $1.16–$5.14

    LCSC

    $2.29–$3.32

    Mouser

    $4.63–$7.34

    TME

    $0.13–$1.22

    Verical

    $10.16–$16.07

    Controls