FAQ
TL;DR: Deep-sleep firmware cuts idle draw from 100 mA to ≈120 µA (-99.9 %) [Elektroda, p.kaczmarek2, post #20456605] “PowerSave alone won’t suffice” [Elektroda, p.kaczmarek2, post #20455596] Update to ≥v1.15.493, erase flash, set DoorSensor pin, then Battery driver. Why it matters: Correct setup turns a 5-hour gadget into a year-long sensor.
Quick Facts
• PCB: PB-69W VER 1.4, CB3S (BK7231N) SoC [Elektroda, 4139ggn, post #20453815]
• Stock current draw: ~100 mA active; deep-sleep: ~120 µA [Elektroda, p.kaczmarek2, post #20456605]
• Power: 2 × AA (typ. 2000 mAh) → ≈1 year in deep-sleep mode (calc.)
• Latest tested OpenBeken: 1.15.493+ [Elektroda, 4139ggn, post #20458005]
• Key pins: P7 Door, P9 Wi-Fi LED, P? Tamper (find via Assign).
How do I stop the CB3S sensor from draining batteries in 5 hours?
- Flash OpenBeken ≥1.15.493. 2. In flasher, click “Erase all”, then “RF Restore”, then write firmware [Elektroda, 4139ggn, post #20458093] 3. In Web UI: Assign DoorSensor to P7, LED_n to P9, save. 4. Enable deep-sleep automatically (built into DoorSensor driver) and leave PowerSave at 1. Current falls from ~100 mA to ≈120 µA, extending life to months [Elektroda, p.kaczmarek2, post #20456605]
What command enables basic power saving?
Enter PowerSave 1 in Short Startup or autoexec.bat. It switches Wi-Fi to dynamic powersave but does not cut current below 100 mA [Elektroda, p.kaczmarek2, post #20455596]
Do I still need a script for PinDeepSleep?
No. When a pin is set to DoorSensor, the DoorSensor driver auto-runs PinDeepSleep after MQTT connects (60 s) or after 300 s offline, waking on edge change [Elektroda, p.kaczmarek2, post #20458219]
Home Assistant shows the entity as unavailable—why?
Availability topics must be omitted because the node sleeps most of the time. Delete the old entity and use automatic MQTT discovery so HA treats it as a sleeping sensor [Elektroda, p.kaczmarek2, post #20456992]
How can I read battery voltage without an external MCU?
Start the built-in Battery driver: add “startDriver Battery; Battery_Setup 2000 3000” to Short Startup. It reports raw voltage and percentage via MQTT [Elektroda, dheenhasty, post #20458124]
I get 0 V and –200 % battery—fix?
Set correct divider and thresholds in Battery_Setup. Example for 2 × AA: Battery_Setup 2000 3000 2.29 (third value = resistor ratio). Wrong values return negatives [Elektroda, dheenhasty, post #20458539]
How do I recover from a boot loop or corrupt firmware?
Pull batteries, wait 3 min to discharge capacitors, then flash via UART: Full erase → RF restore → write new firmware. Device should create its AP again [Elektroda, 4139ggn, post #20457982]
Which pin is the rear tamper switch?
Use Assign → Button on each unused GPIO, save, press the rear switch, and watch console; the pin that logs a change is your tamper pin [Elektroda, dheenhasty, post #20458124]
Can the tamper button publish a disassembly alert?
Yes. Assign that GPIO as Button, then add a rule or script: onPress → publish MQTT topic “sensor/door/tamper=ON”. Expert quote: “It should be possible via scripting.” [Elektroda, p.kaczmarek2, post #20460758]
Edge case: What if the sensor never creates an AP after flashing?
If five power cycles don’t trigger failsafe, battery voltage may be below 2.2 V; replace cells. If still absent, UART log showing random characters indicates corrupted flash—redo full erase + firmware write [Elektroda, dheenhasty, #20456987; #20457782].
3-step How-To: Pair with Home Assistant quickly
- Flash and configure pins; ensure Wi-Fi connects. 2. In Console type scheduleHADiscovery; sensor appears in HA within 10 s [Elektroda, dheenhasty, post #20458124] 3. Remove old entities with availability topics to avoid offline errors.
