might ditch the esp32, this is the best ive gotten with it.

include/protocol.h

@@ -0,0 +1,85 @@
+#pragma once
+
+#include <stdint.h>
+#include <type_traits>
+
+#include <Arduino.h>
+
+namespace mrr {
+
+constexpr uint8_t kControlMagic = 0xAA;
+constexpr uint8_t kTelemetryMagic = 0x55;
+constexpr uint8_t kProtocolVersion = 1;
+constexpr size_t kSensorGroup100Length = 80;
+constexpr size_t kMaxRobotIdLength = 16;
+
+enum class OiModeRequest : uint8_t {
+  kNoChange = 0,
+  kPassive = 1,
+  kSafe = 2,
+  kFull = 3,
+};
+
+enum ActionBits : uint8_t {
+  kActionSeekDock = 0x01,
+  kActionPlaySong = 0x02,
+  kActionLoadSong = 0x04,
+  kActionEnableOi = 0x08,
+};
+
+struct __attribute__((packed)) ControlPacket {
+  uint8_t magic{kControlMagic};
+  uint8_t version{kProtocolVersion};
+  uint16_t seq{};
+  int16_t left_mmps{};
+  int16_t right_mmps{};
+  uint8_t oi_mode{};
+  uint8_t actions{};
+  uint8_t song_slot{};
+  uint8_t checksum{};
+};
+
+static_assert(sizeof(ControlPacket) == 12, "ControlPacket must remain packed");
+
+struct __attribute__((packed)) TelemetryPacketHeader {
+  uint8_t magic{kTelemetryMagic};
+  uint8_t version{kProtocolVersion};
+  uint16_t seq{};
+  uint32_t uptime_ms{};
+  uint32_t last_control_age_ms{};
+  int8_t wifi_rssi_dbm{};
+  uint8_t status_bits{};
+  uint8_t sensor_bytes{};
+  uint8_t robot_id_length{};
+  char robot_id[kMaxRobotIdLength]{};
+};
+
+struct __attribute__((packed)) TelemetryPacketTrailer {
+  int16_t applied_left_mmps{};
+  int16_t applied_right_mmps{};
+  uint16_t last_control_seq{};
+  uint16_t dropped_control_packets{};
+  uint8_t checksum{};
+};
+
+inline uint8_t checksum8(const uint8_t* data, size_t len) {
+  uint32_t sum = 0;
+  for (size_t i = 0; i < len; ++i) {
+    sum += data[i];
+  }
+  return static_cast<uint8_t>(sum & 0xFF);
+}
+
+template <typename T>
+inline uint8_t checksumPayload(const T& pod) {
+  static_assert(std::is_trivially_copyable<T>::value, "checksum payload must be POD");
+  return checksum8(reinterpret_cast<const uint8_t*>(&pod), sizeof(T));
+}
+
+template <typename T>
+inline uint8_t checksumExcludingLastByte(const T& pod) {
+  static_assert(std::is_trivially_copyable<T>::value, "checksum payload must be POD");
+  return checksum8(reinterpret_cast<const uint8_t*>(&pod), sizeof(T) - 1);
+}
+
+}  // namespace mrr