Initial commit

firmware/firmware.ino

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+#include <bluefruit.h>
+#include <Adafruit_LittleFS.h>
+#include <InternalFileSystem.h>
+#include "HX711.h"
+
+//#define calibration_factor -6980.0 // black wired load cell
+#define calibration_factor -5760.0 // orange wired load cell
+
+#define DOUT 30
+#define CLK  27
+
+HX711 scale;
+
+// BLE Service
+BLEDfu  bledfu;  // OTA DFU service
+BLEDis  bledis;  // device information
+BLEUart bleuart; // uart over ble
+BLEBas  blebas;  // battery
+
+void setup()
+{
+  Serial.begin(115200);
+
+
+  scale.begin(DOUT, CLK);
+  digitalWrite(CLK, LOW); // hangs without this
+  scale.set_scale(calibration_factor); //This value is obtained by using the SparkFun_HX711_Calibration sketch
+  scale.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0
+
+  Serial.println("");
+  Serial.println("");
+  Serial.println("Load Cell Demo");
+  Serial.println("--------------\n");
+
+  Bluefruit.autoConnLed(true);
+  Bluefruit.configPrphBandwidth(BANDWIDTH_MAX);
+
+  Bluefruit.begin();
+  Bluefruit.setTxPower(4);
+  Bluefruit.Periph.setConnectCallback(connect_callback);
+  Bluefruit.Periph.setDisconnectCallback(disconnect_callback);
+
+  bledfu.begin();
+
+  bledis.setManufacturer("Tanner");
+  bledis.setModel("Load Cell");
+  bledis.begin();
+
+  bleuart.begin();
+
+  blebas.begin();
+  blebas.write(100);
+
+  startAdv();
+
+  Serial.println("Please use Adafruit's Bluefruit LE app to connect in UART mode");
+}
+
+void startAdv(void)
+{
+  // Advertising packet
+  Bluefruit.Advertising.addFlags(BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE);
+  Bluefruit.Advertising.addTxPower();
+
+  // Include bleuart 128-bit uuid
+  Bluefruit.Advertising.addService(bleuart);
+
+  // Secondary Scan Response packet (optional)
+  // Since there is no room for 'Name' in Advertising packet
+  Bluefruit.ScanResponse.addName();
+  
+  /* Start Advertising
+   * - Enable auto advertising if disconnected
+   * - Interval:  fast mode = 20 ms, slow mode = 152.5 ms
+   * - Timeout for fast mode is 30 seconds
+   * - Start(timeout) with timeout = 0 will advertise forever (until connected)
+   * 
+   * For recommended advertising interval
+   * https://developer.apple.com/library/content/qa/qa1931/_index.html   
+   */
+  Bluefruit.Advertising.restartOnDisconnect(true);
+  Bluefruit.Advertising.setInterval(32, 244);    // in unit of 0.625 ms
+  Bluefruit.Advertising.setFastTimeout(30);      // number of seconds in fast mode
+  Bluefruit.Advertising.start(0);                // 0 = Don't stop advertising after n seconds  
+}
+
+void loop()
+{
+  char buf[100] = "";
+  
+  int reading = (int) scale.get_units();
+  String message = String(reading) + "\n";
+  message.toCharArray(buf, message.length()+1);
+  bleuart.write(buf, message.length()+1);
+  
+  delay(50);
+}
+
+// callback invoked when central connects
+void connect_callback(uint16_t conn_handle)
+{
+  // Get the reference to current connection
+  BLEConnection* connection = Bluefruit.Connection(conn_handle);
+
+  char central_name[32] = { 0 };
+  connection->getPeerName(central_name, sizeof(central_name));
+
+  Serial.print("Connected to ");
+  Serial.println(central_name);
+}
+
+/**
+ * Callback invoked when a connection is dropped
+ * @param conn_handle connection where this event happens
+ * @param reason is a BLE_HCI_STATUS_CODE which can be found in ble_hci.h
+ */
+void disconnect_callback(uint16_t conn_handle, uint8_t reason)
+{
+  (void) conn_handle;
+  (void) reason;
+
+  Serial.println();
+  Serial.print("Disconnected, reason = 0x");
+  Serial.println(reason, HEX);
+}