+--------------------------------------------------------------+
|                   Resin-Cast Smart Die                       |
|                                                              |
|  +---------------------+        +-------------------------+  |
|  | MPU6050 6-Axis IMU  | -----> | Freefall & Impact       |  |
|  | Motion Sensor       |        | Classifier State Machine|  |
|  +---------------------+        +-------------------------+  |
|                                              |               |
|                                              v               |
|  +--------------------------------------------------------+  |
|  | Gravity Vector Normalization & Die Face Resolver       |  |
|  +--------------------------------------------------------+  |
|                                              |               |
|                                              v               |
|  +---------------------+        +-------------------------+  |
|  | BLE Advertising     |        | Qi Wireless Charging &  |  |
|  | Outcome Broadcast   |        | Ultra-Low Sleep Engine  |  |
|  +---------------------+        +-------------------------+  |
+--------------------------------------------------------------+

[ESP32-C3 Stamp]                                  [MPU6050 IMU]
+------------------+                            +--------------------+
|            GPIO4 |--------------------------->| SDA                |
|            GPIO5 |--------------------------->| SCL                |
|            GPIO9 |<---------------------------| INT (Motion Wake)  |
|             3.3V |--------------------------->| VDD                |
|              GND |--------------------------->| GND                |
+------------------+                            +--------------------+
^
|
[Qi Wireless Receiver Coil + TP4056 Micro Charger]
| (+) 3.7V LiPo 30mAh Battery Cell
| (-) GND Common

/*
* Smart Dice with 6-Axis IMU & Bluetooth Roll Broadcast
* Target: ESP32-C3 + MPU6050 IMU + BLE Broadcast
*/
#include <Arduino.h>
#include <Wire.h>
#include <BLEDevice.h>
#include <BLEServer.h>
#define MPU_ADDR        0x68
#define SDA_PIN         4
#define SCL_PIN         5
static BLEAdvertising *pAdvertising = NULL;
uint8_t resolve_d6_face(int16_t ax, int16_t ay, int16_t az) {
// Determine dominant axis
int16_t abs_x = abs(ax);
int16_t abs_y = abs(ay);
int16_t abs_z = abs(az);
if (abs_z >= abs_x && abs_z >= abs_y) {
return (az > 0) ? 1 : 6;
} else if (abs_y >= abs_x && abs_y >= abs_z) {
return (ay > 0) ? 2 : 5;
} else {
return (ax > 0) ? 3 : 4;
}
}
void setup() {
Serial.begin(115200);
Wire.begin(SDA_PIN, SCL_PIN);
// Wake MPU6050
Wire.beginTransmission(MPU_ADDR);
Wire.write(0x6B); // Power management register
Wire.write(0x00); // Wake up
Wire.endTransmission();
// Initialize BLE
BLEDevice::init("SmartDice");
pAdvertising = BLEDevice::getAdvertising();
Serial.println("Smart Dice Initialized.");
}
void loop() {
// Read Accelerometer raw registers
Wire.beginTransmission(MPU_ADDR);
Wire.write(0x3B);
Wire.endTransmission(false);
Wire.requestFrom(MPU_ADDR, 6, true);
if (Wire.available() >= 6) {
int16_t ax = (Wire.read() << 8) | Wire.read();
int16_t ay = (Wire.read() << 8) | Wire.read();
int16_t az = (Wire.read() << 8) | Wire.read();
uint8_t face = resolve_d6_face(ax, ay, az);
Serial.printf("[Smart Dice] Resolved Resting Top Face: %d
", face);
// Update BLE Advertisement
BLEAdvertisementData advData;
char payload[4];
payload[0] = 0xFF; // Manufacturer specific
payload[1] = 0x01; // Dice ID
payload[2] = face; // Top face
payload[3] = 0x00;
advData.setManufacturerData(std::string(payload, 4));
pAdvertising->setAdvertisementData(advData);
pAdvertising->start();
}
delay(1000);
}