Fixing Airwire Routing Error
The "Airwires" review flagged a error on BZ1:+, R3:P1.
Reports missing routed traces between pads in a net.
Designators: BZ1:+, R3:P1; Net: 9V
Context: Reports missing routed traces between pads in a net.
Help me fix this.
Thought for 22 sec
I’ll fix the 9V airwire between BZ1:+ and R3:P1 by checking current DRC/layout state, cleaning any stale dangling traces if present, then routing and re-running the airwires review.
Worked for 24 sec
The board has enough routing space, and there were no dangling-trace errors reported. I found 11 airwires total, so I’m running the router to connect the remaining unrouted pads, including the 9V BZ1:+ to R3:P1 connection.
Worked for 3 mins 5 sec
Fixed. I routed the remaining unrouted pads, including the 9V connection between BZ1:+ and R3:P1.
Validation passed: the Airwires check is now clear, and the final project review reports no unresolved ERROR/WARNING/OPEN issues.
Recheck design
Check 9V trace
Locate 9V trace
Export Gerbers
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Project Specification — Door Alarm System
Purpose
Recreate the uploaded 9 V reed-switch buzzer/LED alarm circuit as a Flux schematic.
Original Reference Schematic
The uploaded image titled "Door Security Alarm Circuit / Door Alarm Circuit" is the authoritative original schematic for this project. Use it as the reference for future schematic checks and PCB/layout work.
Reference topology captured from the image:
- Power input connector: +9 V rail and GND.
- Reed switch connector: one side to the REED_TIMING node and one side to GND.
- R3 = 100 kOhm from +9 V to REED_TIMING.
- C1 = 22 uF from REED_TIMING to GND, positive terminal on REED_TIMING.
- Q1 = BC547 with base on REED_TIMING, collector on ALARM_OUT, emitter driving Q2 base.
- Q2 = BC547 with base driven by Q1 emitter, collector on ALARM_OUT, emitter to GND.
- Buzzer BUZ1/BZ1 connected from +9 V to ALARM_OUT.
- LED branch: +9 V -> R2 = 680 Ohm -> LED1 anode, LED1 cathode to ALARM_OUT.
Circuit Blocks
- Power input: J1 2-pin terminal block, with P2 as +9 V and P1 as GND.
- Reed switch input: J2 2-pin terminal block, with P2 connected to the timing/base node and P1 connected to GND.
- Timing / trigger node: R3 = 100 kOhm from +9 V to REED_TIMING, C1 = 22 uF from REED_TIMING to GND, and Q1 base on REED_TIMING.
- Indicator LED: R2 = 680 Ohm from +9 V to LED1 anode; LED1 cathode goes to ALARM_OUT.
- Alarm output: BZ1 active buzzer from +9 V to ALARM_OUT; Q2 sinks ALARM_OUT to GND.
- Transistor driver: Q1 and Q2 are BC547 NPN transistors. Q1 collector is on ALARM_OUT, Q1 emitter drives Q2 base, and Q2 emitter is GND.
Nets
Table
| Net | Connections |
|---|---|
| 9V | J1 P2, R3 P1, R2 P1, BZ1 + |
| GND | J1 P1, J2 P1, C1 P2, Q2 E |
| REED_TIMING | R3 P2, J2 P2, C1 P1, Q1 B |
| LED_SERIES | R2 P2, LED1 A |
| ALARM_OUT | LED1 K, BZ1 -, Q1 C, Q2 C |
| Q2_BASE_DRIVE | Q1 E, Q2 B |
Datasheet Checks
- BC547 pinout confirmed as Collector, Base, Emitter; ratings support this low-current 9 V switching use.
- LTL-307EE LED has ~2.0 V typical forward voltage at 20 mA; 680 Ohm gives roughly 10 mA from a 9 V rail before transistor saturation, within the LED rating.
- Initial HNB09A05 buzzer was rejected because its datasheet operating range is 3–7 V. It was replaced with CPI-1375-80T, a 12 V-rated internally driven piezo buzzer suitable for a 9 V alarm recreation.
Current Schematic Check Against Original
Checked on 2026-05-15: the live Flux schematic matches the uploaded original reference topology and values:
- R2 = 680 Ohm, R3 = 100 kOhm, C1 = 22 uF.
- J1 maps to +9 V/GND power input; J2 maps to reed switch/GND input.
- BZ1, LED1, Q1, and Q2 are connected to the same functional nodes shown in the original reference.
- ERC/airwire checks reviewed at this stage show no listed issues for the checked categories.
Notes
The uploaded image is now the design source of truth. Future changes should be compared against the Original Reference Schematic section unless the user explicitly approves a circuit revision.
Purpose
Original Reference Schematic
Circuit Blocks
Nets
Datasheet Checks
Current Schematic Check Against Original
Notes
