diff --git a/src/c3nav/mesh/dataformats.py b/src/c3nav/mesh/dataformats.py
index 3e5a3146..f497f15c 100644
--- a/src/c3nav/mesh/dataformats.py
+++ b/src/c3nav/mesh/dataformats.py
@@ -3,7 +3,6 @@ import struct
 from abc import ABC, abstractmethod
 from dataclasses import dataclass, field, fields
 from enum import IntEnum, unique
-from itertools import chain
 from typing import Self, Sequence, Any
 
 from c3nav.mesh.utils import indent_c
@@ -315,21 +314,25 @@ class StructType:
         return cls(**kwargs)
 
     @classmethod
-    def get_c_parts(cls, ignore_fields=None, no_empty=False, typedef=False):
+    def get_c_parts(cls, ignore_fields=None, no_empty=False, typedef=False, union_only=False,
+                    union_member_as_types=False):
         ignore_fields = set() if not ignore_fields else set(ignore_fields)
 
+        pre = ""
+
         items = []
         for field_ in fields(cls):
             if field_.name in ignore_fields:
                 continue
+            name = field_.metadata.get("c_name", field_.name)
             if "format" in field_.metadata:
                 items.append((
-                    field_.metadata["format"].get_c_code(field_.name),
+                    field_.metadata["format"].get_c_code(name),
                     field_.metadata.get("doc", None),
                 )),
             elif issubclass(field_.type, StructType):
                 items.append((
-                    field_.type.get_c_code(field_.name, typedef=False),
+                    field_.type.get_c_code(name, typedef=False),
                     field_.metadata.get("doc", None),
                 ))
             else:
@@ -340,19 +343,39 @@ class StructType:
             parent_fields = set(field_.name for field_ in fields(cls))
             union_items = []
             for key, option in cls._union_options[cls.union_type_field].items():
-                name = normalize_name(getattr(key, 'name', option.__name__))
-                union_items.append(
-                    option.get_c_code(name, ignore_fields=(ignore_fields | parent_fields))
+                base_name = normalize_name(getattr(key, 'name', option.__name__))
+                if union_member_as_types:
+                    struct_name = cls.get_struct_name(base_name)
+                    pre += option.get_c_code(
+                        struct_name,
+                        ignore_fields=(ignore_fields | parent_fields),
+                        typedef=True
+                    )+"\n\n"
+                    union_items.append(
+                        "%s %s;" % (struct_name, cls.get_variable_name(base_name)),
+                    )
+                else:
+                    union_items.append(
+                        option.get_c_code(base_name, ignore_fields=(ignore_fields | parent_fields))
+                    )
+            union_items.append(
+                "uint8_t bytes[%s];" % max(
+                    (option.get_min_size() for option in cls._union_options[cls.union_type_field].values()),
+                    default=0,
                 )
-            items.append((
-                "union {\n"+indent_c("\n".join(union_items))+"\n}",
-                ""))
+            )
+            union_code = "{\n"+indent_c("\n".join(union_items))+"\n}",
+            if union_only:
+                return "typedef union __packed %s" % union_code, "";
+            else:
+                items.append(("union %s;" % union_code, ""))
+        elif union_only:
+            return "", ""
 
         if no_empty and not items:
             return "", ""
 
         # todo: struct comment
-        pre = ""
         if typedef:
             comment = cls.__doc__.strip()
             if comment:
@@ -372,23 +395,31 @@ class StructType:
         return pre, ""
 
     @classmethod
-    def get_c_code(cls, name=None, ignore_fields=None, no_empty=False, typedef=True) -> str:
-        pre, post = cls.get_c_parts(ignore_fields=ignore_fields, no_empty=no_empty, typedef=typedef)
+    def get_c_code(cls, name=None, ignore_fields=None, no_empty=False, typedef=True, union_only=False,
+                   union_member_as_types=False) -> str:
+        pre, post = cls.get_c_parts(ignore_fields=ignore_fields, no_empty=no_empty, typedef=typedef,
+                                    union_only=union_only, union_member_as_types=union_member_as_types,
+                                    )
         if no_empty and not pre and not post:
             return ""
         return "%s %s%s;" % (pre, name, post)
 
     @classmethod
-    def get_base_name(cls):
-        return cls.__name__
+    def get_variable_name(cls, base_name):
+        return base_name
 
     @classmethod
-    def get_variable_name(cls):
-        return cls.get_base_name()
+    def get_struct_name(cls, base_name):
+        return "%s_t" % base_name
 
     @classmethod
-    def get_struct_name(cls):
-        return "%s_t" % cls.get_base_name()
+    def get_min_size(cls) -> int:
+        if cls.union_type_field:
+            return (
+                {f.name: field for f in fields()}[cls.union_type_field].metadata["format"].get_min_size() +
+                sum((option.get_min_size() for option in cls._union_options[cls.union_type_field].values()), start=0)
+            )
+        return sum((f.metadata.get("format", f.type).get_min_size() for f in fields(cls)), start=0)
 
 
 class MacAddressFormat(FixedHexFormat):
@@ -426,6 +457,7 @@ class MultipinLedConfig(LedConfig, StructType, led_type=LedType.MULTIPIN):
     gpio_blue: int = field(metadata={"format": SimpleFormat('B')})
 
 
+@dataclass
 class RangeItemType(StructType):
     address: str = field(metadata={"format": MacAddressFormat()})
     distance: int = field(metadata={"format": SimpleFormat('H')})
diff --git a/src/c3nav/mesh/management/commands/mesh_msg_c.py b/src/c3nav/mesh/management/commands/mesh_msg_c.py
index 034a0bcc..ce06f89f 100644
--- a/src/c3nav/mesh/management/commands/mesh_msg_c.py
+++ b/src/c3nav/mesh/management/commands/mesh_msg_c.py
@@ -2,22 +2,27 @@ from dataclasses import fields
 
 from django.core.management.base import BaseCommand
 
-from c3nav.mesh.dataformats import normalize_name
-from c3nav.mesh.messages import MeshMessage
+from c3nav.mesh.dataformats import normalize_name, LedConfig
+from c3nav.mesh.messages import MeshMessage, MeshMessageType
 from c3nav.mesh.utils import indent_c
 
 
 class Command(BaseCommand):
     help = 'export mesh message structs for c code'
 
+    def shorten_name(self, name):
+        name = name.replace('config', 'cfg')
+        name = name.replace('position', 'pos')
+        name = name.replace('mesh_', '')
+        name = name.replace('firmware', 'fw')
+        return name
+
     def handle(self, *args, **options):
         done_struct_names = set()
         nodata = set()
         struct_lines = {}
 
         ignore_names = set(field_.name for field_ in fields(MeshMessage))
-        from pprint import pprint
-        pprint(MeshMessage.get_msg_types())
         for msg_id, msg_type in MeshMessage.get_msg_types().items():
             if msg_type.c_struct_name:
                 if msg_type.c_struct_name in done_struct_names:
@@ -25,16 +30,22 @@ class Command(BaseCommand):
                 done_struct_names.add(msg_type.c_struct_name)
                 msg_type = MeshMessage.c_structs[msg_type.c_struct_name]
 
-            name = "mesh_msg_%s_t" % (
-                msg_type.c_struct_name or normalize_name(getattr(msg_id, 'name', msg_type.__name__))
-            )
+            base_name = (msg_type.c_struct_name or self.shorten_name(normalize_name(
+                getattr(msg_id, 'name', msg_type.__name__)
+            )))
+            name = "mesh_msg_%s_t" % base_name
+
+            if msg_id == MeshMessageType.CONFIG_LED:
+                msg_type = LedConfig
+
             code = msg_type.get_c_code(name, ignore_fields=ignore_names, no_empty=True)
             if code:
+                struct_lines[base_name] = "%s %s;" % (name, base_name.replace('_announce', ''))
                 print(code)
                 print()
             else:
                 nodata.add(msg_type)
-        return
+
         print("/** union between all message data structs */")
         print("typedef union __packed {")
         for line in struct_lines.values():
@@ -42,14 +53,17 @@ class Command(BaseCommand):
         print("} mesh_msg_data_t;")
         print()
 
-        max_msg_type = max(MeshMessage.msg_types.keys())
+        max_msg_type = max(MeshMessage.get_msg_types().keys())
         macro_data = []
         for i in range(((max_msg_type//16)+1)*16):
-            msg_type = MeshMessage.msg_types.get(i, None)
+            msg_type = MeshMessage.get_msg_types().get(i, None)
             if msg_type:
+                name = (msg_type.c_struct_name or self.shorten_name(normalize_name(
+                    getattr(msg_type.msg_id, 'name', msg_type.__name__)
+                )))
                 macro_data.append((
                     msg_type.get_c_enum_name()+',',
-                    ("nodata" if msg_type in nodata else msg_type.get_c_struct_name())+',',
+                    ("nodata" if msg_type in nodata else name)+',',
                     msg_type.get_var_num(),
                     msg_type.__doc__.strip(),
                 ))
diff --git a/src/c3nav/mesh/messages.py b/src/c3nav/mesh/messages.py
index 1a2ba074..a01b8a1d 100644
--- a/src/c3nav/mesh/messages.py
+++ b/src/c3nav/mesh/messages.py
@@ -9,7 +9,8 @@ from asgiref.sync import async_to_sync
 
 from c3nav.mesh.utils import get_mesh_comm_group, indent_c
 from c3nav.mesh.dataformats import (BoolFormat, FixedStrFormat, FixedHexFormat, LedConfig, LedConfig,
-                                    MacAddressesListFormat, MacAddressFormat, SimpleFormat, VarStrFormat, StructType)
+                                    MacAddressesListFormat, MacAddressFormat, SimpleFormat, VarStrFormat, StructType,
+                                    VarArrayFormat, RangeItemType)
 
 MESH_ROOT_ADDRESS = '00:00:00:00:00:00'
 MESH_PARENT_ADDRESS = '00:00:00:ff:ff:ff'
@@ -120,15 +121,12 @@ class MeshMessage(StructType, union_type_field="msg_id"):
         return sum((getattr(field.metadata["format"], "var_num", 0) for field in fields(cls)), start=0)
 
     @classmethod
-    def get_c_struct_name(cls):
-        return (
-            cls.c_struct_name if cls.c_struct_name else
-            re.sub(
-                r"([a-z])([A-Z])",
-                r"\1_\2",
-                cls.__name__.removeprefix('Mesh').removesuffix('Message')
-            ).lower().replace('config', 'cfg').replace('firmware', 'fw').replace('position', 'pos')
-        )
+    def get_variable_name(cls, base_name):
+        return cls.c_struct_name or base_name
+
+    @classmethod
+    def get_struct_name(cls, base_name):
+        return "mesh_msg_%s_t" % base_name
 
     @classmethod
     def get_c_enum_name(cls):
@@ -316,5 +314,4 @@ class ConfigUplinkMessage(MeshMessage, msg_id=MeshMessageType.CONFIG_UPLINK):
 @dataclass
 class LocateReportRangeMessage(MeshMessage, msg_id=MeshMessageType.LOCATE_REPORT_RANGE):
     """ report distance to given nodes """
-    #ranges: dict[str, int] =
-    pass
\ No newline at end of file
+    ranges: dict[str, int] = field(metadata={"format": VarArrayFormat(RangeItemType)})
\ No newline at end of file