working streaming of raw accel/gyro data. must restart firmware after run of test_basic.py

README.md

@@ -146,3 +146,10 @@ make html
 
 The output will be stored in the ``_build_sphinx`` folder. You may check for
 other output formats other than HTML by running ``make help``.
+
+
+## Resources
+
+This was a useful tutorial for getting a bunch of bluetooth stuff working:
+- https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/lessons/lesson-4-bluetooth-le-data-exchange/topic/blefund-lesson-4-exercise-1/
+- Source code: https://github.com/NordicDeveloperAcademy/bt-fund/blob/main/l4/l4_e1_sol/src/my_lbs.h

firmware/app/src/bt_services.c

@@ -0,0 +1,64 @@
+
+#include <zephyr/types.h>
+#include <stddef.h>
+#include <string.h>
+#include <errno.h>
+#include <zephyr/sys/printk.h>
+#include <zephyr/sys/byteorder.h>
+#include <zephyr/kernel.h>
+
+#include <zephyr/bluetooth/bluetooth.h>
+#include <zephyr/bluetooth/hci.h>
+#include <zephyr/bluetooth/conn.h>
+#include <zephyr/bluetooth/uuid.h>
+#include <zephyr/bluetooth/gatt.h>
+
+#include "bt_services.h"
+
+#include <zephyr/logging/log.h>
+
+LOG_MODULE_DECLARE(main, CONFIG_APP_LOG_LEVEL);
+
+static sensors_raw_t sensors;
+
+void set_sensors(const sensors_raw_t *values)
+{
+    sensors = *values;
+}
+
+// Callback definitions
+static ssize_t read_sensors(struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf,
+                            uint16_t len, uint16_t offset)
+{
+    const char *value = attr->user_data;
+    size_t size = sizeof(sensors_raw_t);
+
+    LOG_INF("Attribute read, handle: %u, conn: %p, bytes: %d", attr->handle, (void *)conn, size);
+
+    return bt_gatt_attr_read(conn, attr, buf, len, offset, value, size);
+}
+
+// Service declaration
+
+static ssize_t read_string(struct bt_conn *conn, const struct bt_gatt_attr *attr, void *buf, uint16_t len, uint16_t offset)
+{
+    const char *value = attr->user_data;
+    LOG_INF("String read, handle: %u, conn: %p\t%s", attr->handle, (void *)conn, value);
+    return bt_gatt_attr_read(conn, attr, buf, len, offset, attr->user_data, strlen((char *)attr->user_data));
+}
+
+BT_GATT_SERVICE_DEFINE(my_lbs_svc, BT_GATT_PRIMARY_SERVICE(BT_UUID_IMU),
+                       // Read raw sensor values
+                       BT_GATT_CHARACTERISTIC(BT_UUID_IMU_SENSORS,
+                                              BT_GATT_CHRC_READ,
+                                              BT_GATT_PERM_READ,
+                                              read_sensors,
+                                              NULL,
+                                              &sensors),
+                       BT_GATT_DESCRIPTOR(BT_UUID_GATT_CUD,
+                                          BT_GATT_PERM_READ,
+                                          read_string,
+                                          NULL,
+                                          "Read raw sensor values"),
+                       // TODO: add characteristic to read state estimate
+);

firmware/app/src/bt_services.h

@@ -0,0 +1,36 @@
+#ifndef BT_SERVICES_H_
+#define BT_SERVICES_H_
+
+// NOTE: these are randomly generated for development
+// https://www.uuidgenerator.net/
+#define BT_UUID_IMU_VAL BT_UUID_128_ENCODE(0xc77cb872, 0xa346, 0x40bf, 0x97a5, 0x3223f6f0a47c)
+#define BT_UUID_IMU_SENSORS_VAL BT_UUID_128_ENCODE(0x99b59474, 0x5570, 0x464b, 0xbe37, 0x64465aa050fd)
+// #define BT_UUID_IMU_EULER_VAL BT_UUID_128_ENCODE()
+// #define BT_UUID_IMU_QUATERNION_VAL BT_UUID_128_ENCODE()
+
+#define BT_UUID_IMU BT_UUID_DECLARE_128(BT_UUID_IMU_VAL)
+#define BT_UUID_IMU_SENSORS BT_UUID_DECLARE_128(BT_UUID_IMU_SENSORS_VAL)
+
+typedef struct
+{
+    double accel_x; ///< [m/s]
+    double accel_y; ///< [m/s]
+    double accel_z; ///< [m/s]
+    double gyro_x;
+    double gyro_y;
+    double gyro_z;
+    double mag_x;
+    double mag_y;
+    double mag_z;
+} sensors_raw_t;
+
+typedef sensors_raw_t (*sensors_cb_t)(void);
+
+struct my_imu_cb
+{
+    sensors_cb_t sensors_cb;
+};
+
+void set_sensors(const sensors_raw_t *values);
+
+#endif // BT_SERVICES_H_

firmware/app/src/main.c

@@ -7,6 +7,8 @@
 #include <app/drivers/blink.h>
 
 #include <app_version.h>
+#include <math.h>
+#include "bt_services.h"
 
 // #include <zephyr/bluetooth/bluetooth.h>
 // #include <zephyr/bluetooth/hci.h>
@@ -317,16 +319,28 @@ int thread_sensors(void)
 		uint8_t pct_bat = 100.0 * (vbat - 3.3) / (4.2 - 3.3);
 		bt_bas_set_battery_level(pct_bat);
 
+		sensors_raw_t values;
+		values.accel_x = accel_x.val1 + accel_x.val2 * 1e-6;
+		values.accel_y = accel_y.val1 + accel_y.val2 * 1e-6;
+		values.accel_z = accel_z.val1 + accel_z.val2 * 1e-6;
+		values.gyro_x = gyro_x.val1 + gyro_x.val2 * 1e-6;
+		values.gyro_y = gyro_y.val1 + gyro_y.val2 * 1e-6;
+		values.gyro_z = gyro_z.val1 + gyro_z.val2 * 1e-6;
+		values.mag_x = NAN;
+		values.mag_y = NAN;
+		values.mag_z = NAN;
+		set_sensors(&values);
+
 		sprintf(str_v, "V :%7.5f", vbat);
 		sprintf(str_i, "I :%7.5f", current.val1 + current.val2 * 1e-6);
 		sprintf(str_p, "P :%7.4f", pressure.val1 + pressure.val2 * 1e-6);
 		sprintf(str_t, "T :%7.4f", temperature.val1 + temperature.val2 * 1e-6);
-		sprintf(str_ax, "AX:%+7.3f", accel_x.val1 + accel_x.val2 * 1e-6);
+		sprintf(str_ax, "AX:%+7.3f", values.accel_x);
-		sprintf(str_ay, "AY:%+7.3f", accel_y.val1 + accel_y.val2 * 1e-6);
+		sprintf(str_ay, "AY:%+7.3f", values.accel_y);
-		sprintf(str_az, "AZ:%+7.3f", accel_z.val1 + accel_z.val2 * 1e-6);
+		sprintf(str_az, "AZ:%+7.3f", values.accel_z);
-		sprintf(str_gx, "GX:%+7.3f", gyro_x.val1 + gyro_x.val2 * 1e-6);
+		sprintf(str_gx, "GX:%+7.3f", values.gyro_x);
-		sprintf(str_gy, "GY:%+7.3f", gyro_y.val1 + gyro_y.val2 * 1e-6);
+		sprintf(str_gy, "GY:%+7.3f", values.gyro_y);
-		sprintf(str_gz, "GZ:%+7.3f", gyro_z.val1 + gyro_z.val2 * 1e-6);
+		sprintf(str_gz, "GZ:%+7.3f", values.gyro_z);
 		sprintf(str_az_ref, "Zr:%+7.3f", accel_z_ref.val1 + accel_z_ref.val2 * 1e-6);
 		sprintf(str_h, "H :%7.3f", humidity.val1 + humidity.val2 * 1e-6);
 

firmware/app/src/peripheral_gatt_write.c

@@ -13,6 +13,8 @@
 #include <zephyr/bluetooth/hci.h>
 #include <zephyr/bluetooth/services/bas.h>
 
+#include "bt_services.h"
+
 extern int mtu_exchange(struct bt_conn *conn);
 extern int write_cmd(struct bt_conn *conn);
 extern struct bt_conn *conn_connected;
@@ -29,7 +31,8 @@ static const struct bt_data ad[] = {
 static unsigned char url_data[] = "\x17//brendanhaines.com";
 
 static const struct bt_data sd[] = {
-	BT_DATA(BT_DATA_URI, url_data, sizeof(url_data) - 1), // -1 to strip \0
+	// BT_DATA(BT_DATA_URI, url_data, sizeof(url_data) - 1), // -1 to strip \0
+	BT_DATA_BYTES(BT_DATA_UUID128_ALL, BT_UUID_IMU_VAL),
 };
 
 static void mtu_updated(struct bt_conn *conn, uint16_t tx, uint16_t rx)

python/test_basic.py

@@ -0,0 +1,39 @@
+# %% imports
+import asyncio
+import time
+
+import numpy as np
+from bleak import BleakClient, BleakScanner
+from matplotlib import pyplot as plt
+
+# %%
+devices = await BleakScanner.discover()
+for d in devices:
+    print(d)
+
+
+# %%
+address = "D7:FC:DA:4B:02:D7"
+MODEL_NBR_UUID = "2A24"
+SENSORS_UUID = "99b594745570464bbe3764465aa050fd"
+
+
+timeseries = list()
+async with BleakClient(address) as client:
+    # model_number = await client.read_gatt_char(MODEL_NBR_UUID)
+    # print("Model Number: {0}".format("".join(map(chr, model_number))))
+    start_time = time.time()
+    print("Starting capture...")
+    while time.time() < start_time + 20:
+        buffer = await client.read_gatt_char(SENSORS_UUID)
+        sensor_values = np.frombuffer(bytes(buffer), dtype=np.double)
+        timeseries.append(sensor_values)
+    print("DONE")
+
+timeseries = np.array(timeseries)
+
+# %%
+plt.plot(timeseries)
+plt.show()
+
+# %%