https://sensorrig.com/tags/hc12/Recent content in Hc12 on SensorRig — Real Raspberry Pi Sensor MonitoringHugoen-usTue, 18 Aug 2026 00:00:00 +0000https://sensorrig.com/posts/hc12-packet-loss-retry-protocol/Tue, 18 Aug 2026 00:00:00 +0000https://sensorrig.com/posts/hc12-packet-loss-retry-protocol/The problem The HC-12 module is marketed as a wireless serial link. You wire it to a UART, set the same baud rate on both ends, and bytes flow. That framing works perfectly — until a byte is corrupted or a channel glitch drops a transmission entirely. There is no CRC at the module level, no retry, no acknowledgement, and no way to tell from the receiving UART alone whether the data that arrived is intact.https://sensorrig.com/posts/esp32c3-deep-sleep-current-real-measurement/Sun, 16 Aug 2026 00:00:00 +0000https://sensorrig.com/posts/esp32c3-deep-sleep-current-real-measurement/The ESP32-C3 datasheet specifies a deep-sleep current of approximately 5–7 µA with the RTC timer on (ESP32-C3 Technical Reference Manual, Section 3.5.3). On my Seeed Studio XIAO ESP32C3, that number is useless. My node is part of a 100-yard shed link running off a 12 V solar panel and a tractor battery, connected to the house over an HC-12 433 MHz serial radio, and the XIAO’s on-board components keep the MCU from ever approaching the silicon floor.https://sensorrig.com/posts/hc12-vs-wifi-remote-sensor-nodes/Mon, 03 Aug 2026 00:00:00 +0000https://sensorrig.com/posts/hc12-vs-wifi-remote-sensor-nodes/Every home-monitoring tutorial assumes WiFi reaches your sensor. Mine didn’t — and for my shed node, it fundamentally couldn’t. The shed sits about 100 yards (~90 m) from the house, runs off-grid on a 12 V solar panel, and its only buffer is the tractor battery wired in for charging only. There is no grid power, no ethernet, and no convenient place to put an access point halfway between. For a node like that, “just use WiFi” collapses immediately: a WiFi board at that distance needs either an outdoor AP and a PoE run (a whole infrastructure project for one sensor), or it simply won’t hold a link.