# EspNowHeartbeat.msg — heartbeat status from ESP-NOW UWB tag (Issue #618)
#
# Published by the ESP-NOW relay node on each MSG_HEARTBEAT (0x30) frame.

std_msgs/Header header

uint8   tag_id        # tag identifier
uint8   battery_pct  # 0-100, or 255 = unknown
uint8   seq_num      # rolling sequence number (detect loss)
uint32  timestamp_ms # ESP32 millis() at time of transmission
