CUB-228: add battery_calibration_offset to cameras table

- Add column to 001_create_tables.sql for fresh databases
- Add migration 002 for existing databases (idempotent via
  pragma_table_info check)
- Implement runIncrementalMigrations in db.go
- Add BatteryCalibrationOffset to Camera model
- Update all camera SELECT queries (cameras List, detail, MQTT
  subscriber getCamera, register)

hardware/README.md

@@ -1,7 +1,7 @@
 # RemoteRig — Camera Node Hardware Design
 
 > **Version:** 0.2.0 | **Status:** Draft  
-> **Target:** GoPro Hero 3 Black/Silver + ESP-01S/ESP8266 + ESP32-C3 Super Mini + USB power bank
+> **Target:** GoPro Hero 3 Black/Silver + ESP8266 + ESP32 + USB power bank
 
 ## Overview
 
@@ -29,8 +29,8 @@ Each camera node is two ESP boards in a small case that clips to the tripod/stan
 
 | Item | Qty | Cost | Notes |
 |------|-----|------|-------|
-| ESP32-C3 Super Mini | 1 | ~$5 | MQTT bridge — talks to hub; board footprint 22.5 × 18.0mm |
-| ESP-01S / ESP8266 | 1 | ~$3 | Camera bridge — talks to GoPro; module envelope 24.7 × 14.3 × 12.0mm |
+| ESP32 Dev Board | 1 | ~$5 | MQTT bridge — talks to hub |
+| ESP8266 D1 Mini | 1 | ~$3 | Camera bridge — talks to GoPro |
 | USB power bank (5000mAh+) | 1 | ~$10 | Powers both boards + GoPro |
 | Micro-USB cable (short) | 2 | ~$2 | Power bank → boards + GoPro |
 | Jumper wires F-F | 3 | ~$0.25 | UART TX/RX/GND between boards |
@@ -45,8 +45,8 @@ Each camera node is two ESP boards in a small case that clips to the tripod/stan
 **Pipeline:** `hardware/DESIGN_PIPELINE.md`
 
 Four exported prototype files:
-1. **Case body** — holds both boards side-by-side with extra wiring/service clearance, cable ports, rear mounting boss
-2. **Case lid** — screw-on cover with ventilation and underside locating lip for flush seating
+1. **Case body** — holds both boards stacked, cable ports, rear dovetail-style receiver
+2. **Case lid** — screw-on cover with ventilation
 3. **Tripod clamp** — separate screw-tightened C-clamp sized around a 35mm stand/pole
 4. **Full preview** — combined visualization STL only, not intended as the print job
 
@@ -105,11 +105,8 @@ The ESP8266 and GoPro talk over Wi-Fi — **no data cable between them**. The on
 
 | | W × D × H (mm) |
 |---|---|
-| Board envelope basis | ESP32-C3 Super Mini: 22.5 × 18.0; ESP-01S: 24.7 × 14.3 × 12.0 |
-| Internal CAD allowance | ~71.2 × 34.0 × 22.0; intentionally includes wiring gutters and vertical connector clearance |
-| Case body external | ~76.0 × 42.6 × 26.0 including rear mount boss depth; main shell ~76.0 × 38.8 × 26.0 |
-| Lid external | ~76.0 × 38.8 × 3.6; includes 1.6mm underside locating lip |
-| Tripod clamp | ~43.0 × 53.5 × 16.0 |
-| Clamp-to-case mount | Two side-by-side M3 screws through flat mounting plate |
+| Case body external | ~56.8 × 38.2 × 19.0 |
+| Lid external | ~56.8 × 32.8 × 4.0 |
+| Tripod clamp | ~43.0 × 56.9 × 16.0 |
 | Clamp pole fit | Nominal 35mm; smaller poles TBD / may need inserts |
 | Total weight | TBD after prototype print |

hardware/case/tripod-case-v3.scad

@@ -1,39 +1,26 @@
 // RemoteRig — Dual-ESP Tripod Case v3
-// v3e changes: board-specific envelope for ESP32-C3 Super Mini + ESP-01S with wiring clearance.
+// v3 changes: screw-tightened tripod clamp + dovetail slide interface.
 // Coordinate system: all case/lid geometry uses bottom-origin Z.
 
 $fn = 36;
 
-// Board dimensions from selected modules.
-// ESP32-C3 Super Mini: 22.5 x 18.0 mm footprint.
-// ESP-01S / ESP8266:   24.7 x 14.3 x 12.0 mm envelope.
-// The case is intentionally larger than board footprints because the field
-// build needs room for Dupont/UART wiring, power leads, bend radius, and fingers.
-esp32c3_w = 22.5; esp32c3_d = 18.0; esp32c3_h = 6.0;   // height allowance includes headers/pins TBD
-esp01s_w  = 24.7; esp01s_d  = 14.3; esp01s_h  = 12.0;
-board_gap = 8.0;     // side-by-side service gap between boards
-wire_x    = 8.0;     // wiring gutter at left/right ends
-wire_y    = 8.0;     // wiring gutter along front/back edges
-wire_z    = 10.0;    // vertical wiring/connector clearance above tallest module
-
-inner_w   = esp32c3_w + esp01s_w + board_gap + wire_x*2;
-inner_d   = max(esp32c3_d, esp01s_d) + wire_y*2;
-inner_h   = max(esp32c3_h, esp01s_h) + wire_z;
+// Board dimensions
+esp8266_w = 34.2; esp8266_d = 25.6; esp8266_h = 5;
+esp32_w   = 52;   esp32_d   = 28;   esp32_h   = 5;
+board_gap = 3;
+stack_h   = esp8266_h + esp32_h + board_gap;
+inner_w   = max(esp8266_w, esp32_w);
+inner_d   = max(esp8266_d, esp32_d);
+inner_h   = stack_h + 2;
 
 // Case parameters
 wall     = 2.0;
 tol      = 0.4;
-outer_w  = inner_w + wall*2 + tol*2;      // 76.0mm with current board/wiring envelope
-outer_d  = inner_d + wall*2 + tol*2;      // 38.8mm with current board/wiring envelope
-outer_h  = inner_h + wall*2;              // 26.0mm with current board/wiring envelope
+outer_w  = inner_w + wall*2 + tol*2;      // 56.8mm
+outer_d  = inner_d + wall*2 + tol*2;      // 32.8mm
+outer_h  = inner_h + wall*2;              // 19mm
 corner_r = 2.5;
 
-// Lid fit parameters
-lid_top_thick = 2.0;
-lid_lip_h     = 1.6;
-lid_clearance = 0.6;   // clearance around underside locating lip
-lid_lip_wall  = 1.2;   // thickness of perimeter lip/frame
-
 // Tripod clamp parameters
 pole_dia      = 35;       // nominal stand/pole diameter
 clamp_thick   = 4.0;      // ring wall thickness
@@ -42,16 +29,15 @@ mouth_width   = 13.0;     // clamp opening
 m3_clearance  = 3.4;      // M3 screw clearance
 nut_flat      = 6.4;      // M3 nut trap flat-to-flat
 
-// Case ↔ clamp interface
-// v3b removes the dovetail: use a flat two-screw mounting plate instead.
-// This is simpler to print, easier to inspect, and field-serviceable.
-mount_plate_w      = 24.0;
-mount_plate_h      = 16.0;
-mount_plate_thick  = 4.0;
-mount_hole_spacing = 14.0;  // side-by-side M3 case-mount screws
-mount_screw_clear  = 3.4;   // M3 clearance through clamp plate
-mount_case_pilot   = 2.7;   // pilot/insert hole through case boss
-mount_boss_r       = 1.2;
+// Dovetail slide interface
+// Male rail is on the case; matching female socket is on the tripod clamp.
+// This is easier to inspect and avoids the previous mismatched "two lips + tab" geometry.
+rail_z         = outer_h * 0.78;
+rail_depth     = 5.0;
+rail_neck_w    = 12.0;   // narrow width at case wall / slot opening
+rail_outer_w   = 18.0;   // wider retained edge
+rail_clearance = 0.45;   // FDM sliding clearance per side-ish
+socket_wall    = 2.2;
 
 // Cable ports
 usb_port_w = 12; usb_port_h = 6;
@@ -121,20 +107,15 @@ module screw_post(x, y) {
     }
 }
 
-module case_mount_boss() {
-    // Flat rear boss on the case. The clamp plate bolts directly to this face.
-    // Holes run front/back (Y axis) for M3 screws, heat-set inserts, or nuts.
-    boss_y = outer_d/2 + mount_plate_thick/2 - 0.2;
-    difference() {
-        translate([0, boss_y, outer_h/2])
-            rounded_cube_centered(mount_plate_w, mount_plate_thick, mount_plate_h, mount_boss_r);
+module case_male_dovetail_rail() {
+    // Positive tapered rail on the case back. Cross-section is narrow at the
+    // wall and wider at the outside, so the clamp socket captures it.
+    translate([0, outer_d/2 - 0.15, outer_h/2])
+        dovetail_prism(rail_z, rail_neck_w, rail_outer_w, rail_depth);
 
-        for (xoff = [-mount_hole_spacing/2, mount_hole_spacing/2]) {
-            translate([xoff, outer_d/2 + mount_plate_thick/2, outer_h/2])
-                rotate([90, 0, 0])
-                    cylinder(d=mount_case_pilot, h=mount_plate_thick + wall*3, center=true, $fn=24);
-        }
-    }
+    // Bottom stop so the clamp socket cannot slide past the case.
+    translate([0, outer_d/2 + rail_depth/2, outer_h*0.12])
+        rounded_cube_centered(rail_outer_w + 3.0, rail_depth + 0.8, 2.4, 0.8);
 }
 
 module case_body() {
@@ -142,48 +123,22 @@ module case_body() {
         case_shell();
         for (x = [-1, 1], y = [-1, 1])
             screw_post(x*(outer_w/2 - 5), y*(outer_d/2 - 5));
-        case_mount_boss();
-    }
-}
-
-module lid_locating_lip() {
-    // Thin underside frame that drops into the case opening. This registers the
-    // lid so it cannot skate/rock on the rim, while staying clear of screw posts.
-    lip_outer_w = inner_w + tol - lid_clearance;
-    lip_outer_d = inner_d + tol - lid_clearance;
-    lip_inner_w = lip_outer_w - lid_lip_wall*2;
-    lip_inner_d = lip_outer_d - lid_lip_wall*2;
-
-    translate([0, 0, -lid_lip_h])
-        difference() {
-            rounded_cube0(lip_outer_w, lip_outer_d, lid_lip_h, 1.0);
-            translate([0, 0, -0.1])
-                rounded_cube0(lip_inner_w, lip_inner_d, lid_lip_h + 0.2, 0.7);
-
-            // Corner reliefs so the lip doesn't interfere with screw posts.
-            for (x = [-1, 1], y = [-1, 1]) {
-                translate([x*(outer_w/2 - 5), y*(outer_d/2 - 5), lid_lip_h/2])
-                    cylinder(d=7.0, h=lid_lip_h + 0.4, center=true, $fn=24);
-            }
+        case_male_dovetail_rail();
     }
 }
 
 module case_lid() {
     difference() {
-        union() {
-            // Thinner top cover; underside lip handles registration.
-            rounded_cube0(outer_w, outer_d, lid_top_thick, 0.8);
-            lid_locating_lip();
-        }
+        rounded_cube0(outer_w, outer_d, wall*2, 1.8);
 
         for (x = [-1, 1], y = [-1, 1]) {
-            translate([x*(outer_w/2 - 5), y*(outer_d/2 - 5), -lid_lip_h - 0.5])
-                cylinder(d=2.4, h=lid_top_thick + lid_lip_h + 1, center=false, $fn=20);
+            translate([x*(outer_w/2 - 5), y*(outer_d/2 - 5), -0.5])
+                cylinder(d=2.4, h=wall*2 + 1, center=false, $fn=20);
         }
 
         for (x = [-outer_w/4, 0, outer_w/4]) {
-            translate([x, 0, lid_top_thick/2])
-                cube([8, outer_d*0.6, lid_top_thick*3], center=true);
+            translate([x, 0, wall*2/2])
+                cube([8, outer_d*0.6, wall*3], center=true);
         }
     }
 }
@@ -192,7 +147,7 @@ module clamp_ring_with_mouth() {
     outer_r = pole_dia/2 + clamp_thick;
     difference() {
         cylinder(r=outer_r, h=clamp_width, center=true, $fn=72);
-        cylinder(r=pole_dia/2 + tol, h=clamp_width + 1, center=true, $fn=72);
+        cylinder(r=pole_dia/2 + rail_clearance, h=clamp_width + 1, center=true, $fn=72);
         // Mouth opens toward +Y. Width is intentionally generous for snap-on placement before tightening.
         translate([0, outer_r, 0])
             cube([mouth_width, outer_r*2, clamp_width + 2], center=true);
@@ -219,21 +174,25 @@ module clamp_ears() {
     }
 }
 
-module clamp_mount_plate() {
+module clamp_dovetail_socket() {
     outer_r = pole_dia/2 + clamp_thick;
-    plate_y = -outer_r - mount_plate_thick/2 + 0.2;
+    socket_outer_w = rail_outer_w + socket_wall*2;
+    socket_depth   = rail_depth + socket_wall*2;
 
-    // Flat plate matching the case boss. Two M3 clearance holes pass through
-    // along Y so the clamp bolts to the case with ordinary hardware.
+    // Solid boss on the rear of the clamp, opposite the tightening mouth.
+    // A matching dovetail void is cut through it along Z so the case rail
+    // slides in from the top/bottom with practical FDM clearance.
     difference() {
-        translate([0, plate_y, 0])
-            rounded_cube_centered(mount_plate_w, mount_plate_thick, mount_plate_h, mount_boss_r);
+        translate([0, -outer_r - socket_depth/2 + socket_wall, 0])
+            rounded_cube_centered(socket_outer_w, socket_depth, clamp_width, 1.2);
 
-        for (xoff = [-mount_hole_spacing/2, mount_hole_spacing/2]) {
-            translate([xoff, plate_y, 0])
-                rotate([90, 0, 0])
-                    cylinder(d=mount_screw_clear, h=mount_plate_thick + 2, center=true, $fn=24);
-        }
+        translate([0, -outer_r - 0.15, 0])
+            dovetail_prism(
+                clamp_width + 1.0,
+                rail_neck_w + rail_clearance,
+                rail_outer_w + rail_clearance,
+                rail_depth + 0.6
+            );
     }
 }
 
@@ -241,7 +200,7 @@ module tripod_clamp() {
     union() {
         clamp_ring_with_mouth();
         clamp_ears();
-        clamp_mount_plate();
+        clamp_dovetail_socket();
     }
 }
 
@@ -252,7 +211,7 @@ module tripod_clip() {
 
 module full_case() {
     case_body();
-    translate([0, 0, outer_h]) case_lid();
+    translate([0, 0, outer_h + 2]) case_lid();
     translate([0, outer_d/2 + pole_dia/2 + clamp_thick + 8, outer_h/2])
         rotate([90, 0, 0]) tripod_clamp();
 }

internal/api/cameras.go

@@ -132,10 +132,10 @@ func GetCameraDetail(database *db.DB) http.HandlerFunc {
 		// Get camera info
 		var c models.Camera
 		err := database.QueryRowContext(r.Context(), `
-			SELECT camera_id, friendly_name, mac_address, created_at, updated_at
+			SELECT camera_id, friendly_name, mac_address, battery_calibration_offset, created_at, updated_at
 			FROM cameras WHERE camera_id = ?
 		`, cameraID).Scan(
-			&c.CameraID, &c.FriendlyName, &c.MacAddress,
+			&c.CameraID, &c.FriendlyName, &c.MacAddress, &c.BatteryCalibrationOffset,
 			&c.CreatedAt, &c.UpdatedAt,
 		)
 		if err == sql.ErrNoRows {

internal/db/db.go

@@ -14,6 +14,9 @@ import (
 //go:embed migrations/001_create_tables.sql
 var migration001 string
 
+//go:embed migrations/002_add_camera_calibration.sql
+var migration002 string
+
 // DB wraps the sql.DB with connection-level settings.
 type DB struct {
 	*sql.DB
@@ -62,6 +65,12 @@ func Open(path string) (*DB, error) {
 			return nil, err
 		}
 		log.Println("Migrations complete")
+	} else {
+		// Run incremental migrations on existing databases
+		if err := runIncrementalMigrations(db); err != nil {
+			db.Close()
+			return nil, err
+		}
 	}
 
 	return &DB{db}, nil
@@ -83,6 +92,25 @@ func migrate(db *sql.DB, sql string) error {
 	return nil
 }
 
+// runIncrementalMigrations applies migrations that haven't been run yet on
+// an existing database (one where the 001 schema already exists).
+func runIncrementalMigrations(db *sql.DB) error {
+	// Migration 002: add battery_calibration_offset if it doesn't exist
+	var colCount int
+	err := db.QueryRow(`SELECT COUNT(*) FROM pragma_table_info('cameras') WHERE name = 'battery_calibration_offset'`).Scan(&colCount)
+	if err != nil {
+		return err
+	}
+	if colCount == 0 {
+		log.Println("Running migration 002: add battery_calibration_offset")
+		if err := migrate(db, migration002); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 // splitSQL splits a SQL string on semicolons, respecting quoted strings.
 func splitSQL(sql string) []string {
 	var stmts []string

internal/db/migrations/001_create_tables.sql

@@ -6,6 +6,7 @@ CREATE TABLE IF NOT EXISTS cameras (
     camera_id                    TEXT PRIMARY KEY,
     friendly_name                TEXT NOT NULL,
     mac_address                  TEXT UNIQUE,
+    battery_calibration_offset   REAL,
     created_at                   DATETIME NOT NULL DEFAULT (datetime('now')),
     updated_at                   DATETIME NOT NULL DEFAULT (datetime('now'))
 );

internal/db/migrations/002_add_camera_calibration.sql

@@ -0,0 +1,5 @@
+-- Migration 002: Add battery_calibration_offset to cameras table
+-- This column stores a per-camera calibration value for converting raw battery
+-- readings (e.g. GoPro Hero 3 byte at offset 57) into percentage values.
+
+ALTER TABLE cameras ADD COLUMN battery_calibration_offset REAL;

internal/mqtt/subscriber.go

@@ -404,9 +404,9 @@ func extractCameraID(topic string) string {
 func getCamera(db *db.DB, cameraID string) (models.Camera, error) {
 	var cam models.Camera
 	err := db.QueryRow(
-		"SELECT camera_id, friendly_name, COALESCE(mac_address,''), created_at, updated_at FROM cameras WHERE camera_id = ?",
+		"SELECT camera_id, friendly_name, COALESCE(mac_address,''), COALESCE(battery_calibration_offset, NULL), created_at, updated_at FROM cameras WHERE camera_id = ?",
 		cameraID,
-	).Scan(&cam.CameraID, &cam.FriendlyName, &cam.MacAddress, &cam.CreatedAt, &cam.UpdatedAt)
+	).Scan(&cam.CameraID, &cam.FriendlyName, &cam.MacAddress, &cam.BatteryCalibrationOffset, &cam.CreatedAt, &cam.UpdatedAt)
 	return cam, err
 }
 

pkg/models/camera.go

@@ -10,6 +10,7 @@ type Camera struct {
 	CameraID                  string    `json:"camera_id"`
 	FriendlyName              string    `json:"friendly_name"`
 	MacAddress                string    `json:"mac_address,omitempty"`
+	BatteryCalibrationOffset  *float64  `json:"battery_calibration_offset,omitempty"`
 	CreatedAt                 time.Time `json:"created_at"`
 	UpdatedAt                 time.Time `json:"updated_at"`
 }