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| author | Sadeep Madurange <sadeep@asciimx.com> | 2026-01-09 16:45:56 +0800 |
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| committer | Sadeep Madurange <sadeep@asciimx.com> | 2026-01-09 16:45:56 +0800 |
| commit | a851a2d646f439f7126c232ba1524c55a8990872 (patch) | |
| tree | 0d8870fae739b72e37fc3ce1a672388ce7592a9c /_site/log/fpm-door-lock-lp/index.html | |
| parent | 3b0f6bd6879d8a32d89dcccc739a73e0e9e823a7 (diff) | |
| download | www-a851a2d646f439f7126c232ba1524c55a8990872.tar.gz | |
Remove _site from git.
Diffstat (limited to '_site/log/fpm-door-lock-lp/index.html')
| -rw-r--r-- | _site/log/fpm-door-lock-lp/index.html | 110 |
1 files changed, 0 insertions, 110 deletions
diff --git a/_site/log/fpm-door-lock-lp/index.html b/_site/log/fpm-door-lock-lp/index.html deleted file mode 100644 index a39a34e..0000000 --- a/_site/log/fpm-door-lock-lp/index.html +++ /dev/null @@ -1,110 +0,0 @@ -<!DOCTYPE html> -<html> - <head> - <meta charset="utf-8"> - <meta name="viewport" content="width=device-width, initial-scale=1"> - <title>Fingerprint door lock (LP)</title> - <link rel="stylesheet" href="/assets/css/main.css"> - <link rel="stylesheet" href="/assets/css/skeleton.css"> -</head> - - - <body> - - <div id="nav-container" class="container"> - <ul id="navlist" class="left"> - - <li > - <a href="/" class="link-decor-none">hme</a> - </li> - <li > - <a href="/projects/" class="link-decor-none">poc</a> - </li> - <li > - <a href="/about/" class="link-decor-none">abt</a> - </li> - <li> - <a href="/cgi-bin/find.cgi" class="link-decor-none">lup</a> - </li> - <li> - <a href="/feed.xml" class="link-decor-none">rss</a> - </li> - </ul> -</div> - - - - <main> - <div class="container"> - <div class="container-2"> - <h2 class="center" id="title">FINGERPRINT DOOR LOCK (LP)</h2> - <h5 class="center">18 AUGUST 2025</h5> - <br> - <div class="twocol justify"><p>Second iteration of the <a href="../fpm-door-lock-rf">RF door lock</a>. Old version worked -but drew too much quiescent current. Sensor and servo pulled 13.8mA and 4.6mA -idle. Linear regulators were a disaster. Battery didn’t last 24 hours.</p> - -<video style="max-width:100%;" controls="" poster="pcb.jpg"> - <source src="video.mp4" type="video/mp4" /> -</video> - -<p>Redesigned the PCB completely. Tossed RF modules and the second MCU. Connected -R503 directly to the ATmega328P. Sensor now mounts on door exterior, servo -attaches to interior knob, MCU stays on the back to prevent tampering.</p> - -<table style="border: none; width: 100%"> - <tr style="border: none;"> - <td style="border: none; width: 49.9%; background-color: transparent; text-align: center;"> - <img src="breadboard.jpg" alt="PCB" style="width: 100%" /> - </td> - <td style="border: none; background-color: transparent; text-align: center;"> - <img src="pcb1.jpg" alt="Design" style="width: 100%" /> - </td> - </tr> - <tr style="border: none;"> - <td colspan="2" style="border: none; background-color: transparent; text-align: center;"> - <img src="footprint.png" alt="PCB footprint" style="width: 100%" /> - </td> - </tr> -</table> - -<p>PCB specs: 2-layer, 1oz copper, 0.3mm traces (1mm for power and servo). Ground -plane on bottom layer.</p> - -<p>Solved idle power draw with MOSFETs. 2N7000 and NDP6020P cut power to sensor -and servo before deep sleep. Through-hole MOSFETs that switch at 3.3V are -getting harder to find. NDP6020P already obsolete.</p> - -<p>Replaced linear regulators with MP1584EN DC-DC buck converters. No RFM–noise -isn’t a big concern. Buck’s pin breakout not great–wouldn’t fit commercial dev -boards.</p> - -<p>Squeezed more power savings by underclocking MCU to 8MHz/3.3V. Combined -with buck converters: 56% total power savings.</p> - -<p>Wake sequence: MCU activates FPM MOSFET, unlocks FPM over UART, scans and -matches fingerprint. Match triggers blue LED, servo MOSFET, PWM signal to -unlock. No match triggers red LED. MOSFETs off, back to sleep.</p> - -<p>Total power savings: 99.9% (30.6mA → 2.9μA). Verdict: Fixed.</p> - -<p>Commit: -<a href="https://git.asciimx.com/fpm-door-lock/commit/?id=75290945b2fd84b3bc108fd46419ee478eaac3ca">7529094</a> -| Gerber: <a href="gerber.zip">gerber.zip</a></p> -</div> - <p class="post-author right">by W. D. Sadeep Madurange</p> - </div> - </div> - </main> - - <div class="footer"> - <div class="container"> - <div class="twelve columns right container-2"> - <p id="footer-text">© ASCIIMX - 2026</p> - </div> - </div> -</div> - - - </body> -</html> |