diff --git a/microSWIFT_V2.2/Core/Components/Inc/iridium.h b/microSWIFT_V2.2/Core/Components/Inc/iridium.h
index 20f9a29..997eb24 100644
--- a/microSWIFT_V2.2/Core/Components/Inc/iridium.h
+++ b/microSWIFT_V2.2/Core/Components/Inc/iridium.h
@@ -4,6 +4,7 @@
  *  Created on: Oct 28, 2022
  *      Author: Phil
  */
+// clang-format off
 
 #ifndef SRC_IRIDIUM_H_
 #define SRC_IRIDIUM_H_
@@ -46,7 +47,6 @@
 #define SBDD_RESPONSE_SIZE 20U
 #define SBDIX_WAIT_TIME ONE_SECOND * 13U
 #define ERROR_MESSAGE_TYPE 99U
-#define IRIDIUM_CHECKSUM_LENGTH sizeof(iridium_checksum_t)
 #define IRIDIUM_MAX_RESPONSE_SIZE 64U
 #define IRIDIUM_DEFAULT_BAUD_RATE 19200U
 #define CHECKSUM_FIRST_BYTE_INDEX 327U
diff --git a/microSWIFT_V2.2/Core/Inc/sbd.h b/microSWIFT_V2.2/Core/Inc/sbd.h
index 740fcb6..a1c0967 100644
--- a/microSWIFT_V2.2/Core/Inc/sbd.h
+++ b/microSWIFT_V2.2/Core/Inc/sbd.h
@@ -4,6 +4,7 @@
  *  Created on: Sep 18, 2024
  *      Author: philbush
  */
+// clang-format off
 
 #ifndef INC_SBD_H_
 #define INC_SBD_H_
@@ -12,7 +13,6 @@
 #include "NEDWaves/rtwhalf.h"
 #define TYPE_99_CHAR_BUF_LEN 320
 #define IRIDIUM_SBD_MAX_LENGTH 340
-#define IRIDIUM_SBD_OVERHEAD_BYTES 2
 #define TELEMETRY_FIELD_ERROR_CODE (0x70E2)
 
 // @formatter:off
@@ -22,6 +22,7 @@ typedef struct
   uint8_t     checksum_a;
   uint8_t     checksum_b;
 } iridium_checksum_t;
+#define IRIDIUM_CHECKSUM_LENGTH sizeof(iridium_checksum_t)
 
 // Primary message type for wave dynamic measurements
 typedef struct __packed
@@ -64,7 +65,7 @@ typedef struct __packed
   uint16_t    ambient_avgs[17];
 } sbd_message_type_53_element;
 
-#define TURBIDITY_MSGS_PER_SBD ((IRIDIUM_SBD_MAX_LENGTH - IRIDIUM_SBD_OVERHEAD_BYTES) / sizeof(sbd_message_type_53_element))
+#define TURBIDITY_MSGS_PER_SBD ((IRIDIUM_SBD_MAX_LENGTH - IRIDIUM_CHECKSUM_LENGTH) / sizeof(sbd_message_type_53_element))
 
 // Definition for the SBD message with multiple sample windows
 typedef struct __packed
@@ -102,7 +103,7 @@ typedef struct __packed
   uint16_t    avg_nir;
 } sbd_message_type_54_element;
 
-#define LIGHT_MSGS_PER_SBD ((IRIDIUM_SBD_MAX_LENGTH - IRIDIUM_SBD_OVERHEAD_BYTES) / sizeof(sbd_message_type_54_element))
+#define LIGHT_MSGS_PER_SBD ((IRIDIUM_SBD_MAX_LENGTH - IRIDIUM_CHECKSUM_LENGTH) / sizeof(sbd_message_type_54_element))
 
 // Definition for the SBD message with multiple sample windows
 typedef struct __packed
@@ -115,6 +116,64 @@ typedef struct __packed
   iridium_checksum_t          checksum;
 } sbd_message_type_54;
 
+// Definition for accelerometer waves message; based heavily on type_52 for the
+// waves component.
+typedef struct __packed
+{
+  char legacy_number_7;  // byte 0
+  uint8_t type;  // byte 1
+
+  // I'm hoping we can omit this, otherwise will have to find 3 bytes elsewhere
+  // uint8_t             port;
+  // uint16_t            size;
+
+  uint32_t timestamp; // byte 2-5
+
+  float latitude;  // byte 6-9
+  float longitude;  // byte 10-13
+
+  // bit 0-1: sensitivity (+/- 2, 4, 8g) == {00, 01, 10}
+  // bit 2: == 0 for low-rate spectra; == 1 for high-rate
+  // bit 3: ==0 for background/duty-cycle; == 1 for wake-on-shake
+  // bit 4-7: threshold for wake-on-shake; TODO: define how this translates to counts
+  uint8_t config;  // byte 14
+  // bit 0-3: count of wake-on-shake events since last duty cycle
+  // bit 4-7: TBD
+  uint8_t status;  // byte 15
+
+  uint16_t min_x_accel;  // byte 16-21
+  uint16_t max_x_accel;
+  uint16_t mean_x_accel;
+
+  uint16_t min_y_accel;  // byte 22-27
+  uint16_t max_y_accel;
+  uint16_t mean_y_accel;
+
+  uint16_t min_z_accel;  // byte 28-33
+  uint16_t max_z_accel;
+  uint16_t mean_z_accel;
+
+  // at 34 bytes here...
+
+  // the Waves component is 204 bytes
+  real16_T Hs;
+  real16_T Tp;
+  real16_T Dp;
+  real16_T E_array[42];
+  real16_T f_min;
+  real16_T f_max;
+  signed char a1_array[42];
+  signed char b1_array[42];
+  signed char a2_array[42];
+  signed char b2_array[42];
+  unsigned char cf_array[42];
+
+  // 2 bytes for the checksum; this MUST be the final element in the struct,
+  // since the iridium thread calculates the checksum and calls memcpy on
+  // payload[sizeof(sbd_message_type_55) - IRIDIUM_CHECKSUM_LENGTH]
+  iridium_checksum_t  checksum;
+} sbd_message_type_55;
+
 typedef struct
 {
   char                  message_body[TYPE_99_CHAR_BUF_LEN];