From a851a2d646f439f7126c232ba1524c55a8990872 Mon Sep 17 00:00:00 2001 From: Sadeep Madurange Date: Fri, 9 Jan 2026 16:45:56 +0800 Subject: Remove _site from git. --- _site/log/fpm-door-lock-rf/back.jpeg | Bin 34023 -> 0 bytes _site/log/fpm-door-lock-rf/back_design.jpeg | Bin 31946 -> 0 bytes _site/log/fpm-door-lock-rf/front.jpeg | Bin 28997 -> 0 bytes _site/log/fpm-door-lock-rf/front_design.jpeg | Bin 32174 -> 0 bytes _site/log/fpm-door-lock-rf/gerber_back.zip | Bin 48217 -> 0 bytes _site/log/fpm-door-lock-rf/gerber_front.zip | Bin 49605 -> 0 bytes _site/log/fpm-door-lock-rf/index.html | 125 --------------------------- _site/log/fpm-door-lock-rf/source.tar.gz | Bin 6660 -> 0 bytes _site/log/fpm-door-lock-rf/thumb_sm.jpeg | Bin 6181 -> 0 bytes 9 files changed, 125 deletions(-) delete mode 100644 _site/log/fpm-door-lock-rf/back.jpeg delete mode 100644 _site/log/fpm-door-lock-rf/back_design.jpeg delete mode 100644 _site/log/fpm-door-lock-rf/front.jpeg delete mode 100644 _site/log/fpm-door-lock-rf/front_design.jpeg delete mode 100644 _site/log/fpm-door-lock-rf/gerber_back.zip delete mode 100644 _site/log/fpm-door-lock-rf/gerber_front.zip delete mode 100644 _site/log/fpm-door-lock-rf/index.html delete mode 100644 _site/log/fpm-door-lock-rf/source.tar.gz delete mode 100644 _site/log/fpm-door-lock-rf/thumb_sm.jpeg (limited to '_site/log/fpm-door-lock-rf') diff --git a/_site/log/fpm-door-lock-rf/back.jpeg b/_site/log/fpm-door-lock-rf/back.jpeg deleted file mode 100644 index f458e69..0000000 Binary files a/_site/log/fpm-door-lock-rf/back.jpeg and /dev/null differ diff --git a/_site/log/fpm-door-lock-rf/back_design.jpeg b/_site/log/fpm-door-lock-rf/back_design.jpeg deleted file mode 100644 index b6c0f5d..0000000 Binary files a/_site/log/fpm-door-lock-rf/back_design.jpeg and /dev/null differ diff --git a/_site/log/fpm-door-lock-rf/front.jpeg b/_site/log/fpm-door-lock-rf/front.jpeg deleted file mode 100644 index 2b2931f..0000000 Binary files a/_site/log/fpm-door-lock-rf/front.jpeg and /dev/null differ diff --git a/_site/log/fpm-door-lock-rf/front_design.jpeg b/_site/log/fpm-door-lock-rf/front_design.jpeg deleted file mode 100644 index f81f09c..0000000 Binary files a/_site/log/fpm-door-lock-rf/front_design.jpeg and /dev/null differ diff --git a/_site/log/fpm-door-lock-rf/gerber_back.zip b/_site/log/fpm-door-lock-rf/gerber_back.zip deleted file mode 100644 index 26659ad..0000000 Binary files a/_site/log/fpm-door-lock-rf/gerber_back.zip and /dev/null differ diff --git a/_site/log/fpm-door-lock-rf/gerber_front.zip b/_site/log/fpm-door-lock-rf/gerber_front.zip deleted file mode 100644 index 864334e..0000000 Binary files a/_site/log/fpm-door-lock-rf/gerber_front.zip and /dev/null differ diff --git a/_site/log/fpm-door-lock-rf/index.html b/_site/log/fpm-door-lock-rf/index.html deleted file mode 100644 index 55675ff..0000000 --- a/_site/log/fpm-door-lock-rf/index.html +++ /dev/null @@ -1,125 +0,0 @@ - - - - - - Fingerprint door lock (RF) - - - - - - - - - - - -
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FINGERPRINT DOOR LOCK (RF)

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05 JUNE 2025
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Wanted to unlock door with fingerprint, wirelessly to avoid drilling.

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2024-11: Started with basic 433MHz RF modules and two Arduinos. Connected data -lines of the transceivers to UART RXD/TXD of an ATmega328P. -Unreliable–constant packet loss.

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2025-01: Switched to RFM69 modules. Complete ball-ache. Followed datasheet to -the letter, audited code many times, cross-checked with RadioHead and RFM69 -open-source drivers. No luck.

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Datasheet riddled with ambiguity.

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ATmega328P runs at 5V; RFM69 3.3V. Suspect logic-level converter (LLC) -issues. High resistance. Not enough swing.

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2025-04: Ditched RFM69s. Switched to NRF24L01+ modules– data pins 5V tolerant, -no LLC required. Spent six weekends writing driver from scratch–clean-room. -Works like a charm.

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2025-05: Wrote FPM drivers for R503 and FPM10A. UART RX sequence was -tricky–adopted Adafruit C++ FOSS implementation to C. R503 has built-in LEDs -and better form factor. Chose it for the lock.

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2025-06: Two PCB boards for FPM (front) and servo (back) controllers. Encrypted -RF link between them.

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- Design (front) -

Footprint (front)

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PCB (front)

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Footprint (back)

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PCB (back)

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PCB specs: 2-layer, 1oz copper, 0.3mm traces (0.5mm for power). Ground plane.

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2025-06: NRF24L01+ on the back stopped working after mounting on PCB. Too close -to servo’s PWM line. Soldering a large 47uF (16V) electrolytic capacitor -between VCC and ground fixed it.

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Power problems became clear. Linear regulators dissipated too much heat. Sensor -and servo drew 13.8mA and 4.6mA quiescent currents–unacceptable for battery. -Servo inrush current exceeds 1A. 0.3mm tracks cuts it too close.

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Verdict: Functional but not practical. Battery dead in under 24 hours. Led to -redesign with proper power management.

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Commit: -f4b0b73 -| Gerber: gerber_back.zip, -gerber_front.zip

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by W. D. Sadeep Madurange

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© ASCIIMX - 2026

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