commit 56863e8398a23a590de0cff8dbdd8af8bfbcc7d6
Author: Diogo Cruz Diniz <diogocruzdiniz@gmail.com>
Date:   Sat Jul 25 16:20:19 2026 +0100

    feat: Basic read/write characteristic

diff --git a/driver.h b/driver.h
new file mode 100644
index 0000000..a139bf7
--- /dev/null
+++ b/driver.h
@@ -0,0 +1,2 @@
+#define BOARD_SCREEN_COMBO 505 // 1.54 inch monochrome ePaper Screen
+#define USE_XIAO_EPAPER_BREAKOUT_BOARD
\ No newline at end of file
diff --git a/scoobytag.ino b/scoobytag.ino
new file mode 100644
index 0000000..e5ee733
--- /dev/null
+++ b/scoobytag.ino
@@ -0,0 +1,114 @@
+
+#include <bluefruit.h>
+
+#include "TFT_eSPI.h"
+
+#define SCBT_BLUETOOTH_PIN "123456"
+
+// 69420    ...  ... 42069
+// 00010F2C-DEAD-BEEF-A455-DEAD69BEEF69
+const uint8_t SCBT_UUID_SERVICE[] =
+{
+  0x69, 0xEF, 0xBE, 0x69, 0xAD, 0xDE, 0x55, 0xA4,
+  0xEF, 0xBE, 0xAD, 0xDE, 0x2C, 0x0F, 0x01, 0x00
+};
+// 00010F2D-DEAD-BEEF-A455-DEAD69BEEF69
+const uint8_t SCBT_UUID_CHR_PET[] =
+{
+  0x69, 0xEF, 0xBE, 0x69, 0xAD, 0xDE, 0x55, 0xA4,
+  0xEF, 0xBE, 0xAD, 0xDE, 0x2D, 0x0F, 0x01, 0x00
+};
+
+BLEService scbtSvc(SCBT_UUID_SERVICE);
+BLECharacteristic scbtPet(SCBT_UUID_CHR_PET);
+
+EPaper epaper;
+
+void setup() {
+  Serial.begin(115200);
+
+  pinMode(LED_GREEN, OUTPUT);
+  pinMode(LED_RED, OUTPUT);
+
+  epaper.begin();
+  epaper.fillScreen(TFT_WHITE);
+  epaper.drawFastHLine(0, 0, 32, TFT_BLACK);
+  epaper.drawRect(19, 19, 102, 22, TFT_BLACK);
+  epaper.update();
+  epaper.setTextSize(2);
+
+  // Init as peripheral
+  Bluefruit.begin(1, 0);
+  Bluefruit.setTxPower(4);
+  Bluefruit.autoConnLed(false);
+  Bluefruit.Security.setPIN(SCBT_BLUETOOTH_PIN);
+  Bluefruit.Periph.setConnectCallback(connectCallback);
+  Bluefruit.Periph.setDisconnectCallback(diconnectCallback);
+
+  // Init service
+  scbtSvc.begin();
+
+  // Init pet
+  scbtPet.setProperties(CHR_PROPS_WRITE | CHR_PROPS_READ);
+  scbtPet.setPermission(SECMODE_OPEN, SECMODE_OPEN);
+  scbtPet.setFixedLen(4);
+  scbtPet.begin();
+  scbtPet.setWriteCallback(scbtPetWriteCallback);
+
+  // Setup advertising
+  Bluefruit.Advertising.addFlags(BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE);
+  Bluefruit.Advertising.addTxPower();
+
+  // Add service
+  Bluefruit.Advertising.addService(scbtSvc);
+
+  // Set name for secondary scan response
+  Bluefruit.setName("Scbt");
+  Bluefruit.Advertising.addName();
+
+  // Start advertising
+  Bluefruit.Advertising.restartOnDisconnect(true);
+  Bluefruit.Advertising.setInterval(32, 2056); // *.625ms = 20ms and 1285ms; see https://developer.apple.com/library/content/qa/qa1931/_index.html
+  Bluefruit.Advertising.setFastTimeout(30);
+  Bluefruit.Advertising.start(0);
+
+  Serial.println("=== START ===");
+}
+
+void connectCallback(uint16_t conn_handle)
+{
+  (void)conn_handle;
+}
+
+void diconnectCallback(uint16_t conn_handle, uint8_t reason)
+{
+  (void)conn_handle;
+  (void)reason;
+  Bluefruit.Advertising.start(0); //Resume adverstising
+}
+
+void scbtPetWriteCallback(uint16_t conn_hdl, BLECharacteristic *chr, uint8_t *data, uint16_t len)
+{
+  (void)conn_hdl;
+  (void)chr;
+  (void)len; //Always 4
+
+  uint32_t value = *(uint32_t*)data;
+
+  char str[32] = { 0 };
+  sprintf(str, "Got pet write %d\n", value);
+  Serial.write(str);
+
+  if (value == 0)
+    digitalWrite(LED_RED, LOW);
+  else
+    digitalWrite(LED_RED, HIGH);
+}
+
+void loop() {
+  digitalWrite(LED_GREEN, LOW);
+  delay(1);
+  digitalWrite(LED_GREEN, HIGH);
+  delay(3999);
+  Serial.write("Alive\n");
+}