Scuba Tank Dive Tracker

Firmware for a Heltec Vision Master E290 / ESP32-S3 e-paper dive display.

The sketch is self-contained: it connects to WiFi, logs in to Subsurface Cloud, fetches /api/stats, optionally reads a public calendar .ics feed for the next dive, updates the e-paper display, then sleeps until the next daily update or optional reed-switch wake.

Configure

Edit the EDIT THESE SETTINGS section near the top of Scuba_Tank_Dive_Tracker.ino. Most users should only need this block:

const char* WIFI_NAME = "YOUR_2G_WIFI_NAME";
const char* WIFI_PASSWORD = "YOUR_WIFI_PASSWORD";

const char* SUBSURFACE_USERNAME = "";
const char* SUBSURFACE_PASSWORD = "";

const char* CALENDAR_LINK = "";

const bool USE_REED_SWITCH = true;
const bool USE_AUTO_ROTATION = true;
const int SCREEN_ROTATION = 0;

const int LOW_BATTERY_PERCENT = 10;

Set USE_REED_SWITCH to false for builds without the magnetic reed switch. Set USE_AUTO_ROTATION to false for builds without the IMU/9DOF board, then choose SCREEN_ROTATION as 0, 90, 180, or 270.

The ESP32-S3 only supports 2.4 GHz WiFi.

Battery

The Vision Master E290 battery sense path uses:

• GPIO7 for ADC voltage
• GPIO46 as INPUT_PULLUP
• scale multiplier 4.90

If the estimated battery is at or below LOW_BATTERY_PERCENT, the daily update shows only a battery symbol and charge now instead of dive stats.

Build And Upload

Open Scuba_Tank_Dive_Tracker.ino in the Arduino IDE, select the Heltec Vision Master E290 / ESP32-S3 board support you use for your device, edit the settings block, then upload over USB.