Third Eye Kit, Node C: Manual/Tactile Scanning (Gloves)
==========================================================

MICROCONTROLLER: Arduino Mini Pro (3.3V)
STATUS: [IN DEV], Glove enclosure not yet fabricated (per node_c.ino)

SENSOR WIRING (HC-SR04 Ultrasonic, hand-held):
────────────────────────────────────────────────
  Sensor Pin | Arduino Pin | Function
  ─────────────────────────────────────
  VCC        | +5V         | Power (5V) [see NOTE below]
  GND        | GND         | Ground
  TRIG       | D9          | Trigger pulse
  ECHO       | D10         | Echo measurement

HAPTIC (Vibration Motor, low intensity):
───────────────────────────────────────────
  Motor Pin  | Arduino Pin | Function
  ─────────────────────────────────────
  Positive   | D5          | Control signal
  Negative   | GND         | Ground

POWER:
──────
  Platform per node_c.ino header comment: Arduino Mini Pro (3.3V)
  Connected to Arduino RAW pin or USB power during development

FIRMWARE CONFIGURATION (node_c.ino):
────────────────────────────────────
  #define TRIG_PIN      9      // Trigger pin
  #define ECHO_PIN      10     // Echo pin
  #define HAPTIC_PIN    5      // Haptic motor (low intensity)
  #define ALERT_CM      40     // Alert distance in cm (arm's reach)

TUNING NOTES:
─────────────
- ALERT_CM (40 cm) targets arm's-reach detection for hand-guided exploration
- BUILD.md does not give a documented tuning range for Node C (unlike Nodes
  A/B); adjust based on field testing and document the final value in the
  build log
- Sample rate is higher than A/B (50 ms loop delay in node_c.ino) for more
  responsive hand-guided scanning

TESTING:
────────
1. Upload firmware to Arduino Mini
2. Open Serial Monitor (9600 baud)
3. Slowly move obstacle (hand, book) across sensor cone
4. Verify haptic pulse fires when distance < ALERT_CM
5. Adjust ALERT_CM until feedback distance feels natural for hand-guided use

TROUBLESHOOTING:
─────────────────
- No haptic feedback: check HAPTIC_PIN (D5) wiring and motor driver
- Distance always 0: check HC-SR04 power and pin connections (D9 TRIG / D10 ECHO)
- Erratic readings: sensor may be damaged; try spare HC-SR04

NOTE:
─────
- BUILD.md's Node C pinout section documents TRIG/ECHO/haptic pin
  assignments but does not state the HC-SR04's supply voltage for this node.
  The VCC (+5V) row above follows the same HC-SR04 wiring pattern documented
  for Node A (node-a-pinout.txt), since HC-SR04 modules are commonly rated
  for 5V. This is a real ambiguity worth flagging: node_c.ino's own header
  comment states the platform is "Arduino Mini Pro (3.3V)" only (not "3.3V
  or 5V" like Node A), so powering a 5V-rated sensor on a 3.3V-only board
  may require a regulator or level-shifting that is not documented anywhere
  in this repo. Verify actual sensor voltage tolerance before building.