scripts: add extra folder with named_value_float_echo.lua

scripts/ardupilot/extra/named_value_float_echo.lua

@@ -0,0 +1,55 @@
+local NAMED_VALUE_FLOAT = {}
+NAMED_VALUE_FLOAT.id = 251
+NAMED_VALUE_FLOAT.fields = {
+    { "time_boot_ms", "<I4" },
+    { "value", "<f" },
+    { "name", "<c10" },
+}
+
+local function decode_named_value_float(message)
+    local result = {}
+    local offset = 2  -- Start from the second byte
+
+    for _, field in ipairs(NAMED_VALUE_FLOAT.fields) do
+        local value
+        local success, err = pcall(function()
+            value, offset = string.unpack(field[2], message, offset)
+        end)
+        if not success then
+            return nil
+        end
+        result[field[1]] = value
+    end
+    return result
+end
+
+local function bytes_to_string(str)
+    return str:match("^%z*(.-)%z*$")  -- Remove leading and trailing null bytes
+end
+
+local function hex_dump(str)
+    return (str:gsub('.', function (c) return string.format('%02X ', string.byte(c)) end))
+end
+
+mavlink.init(1, 10)
+mavlink.register_rx_msgid(NAMED_VALUE_FLOAT.id)
+
+function update()
+    local msg, _, timestamp_ms = mavlink.receive_chan()
+    if msg then
+
+        local header = msg:sub(1, 10)  -- MAVLink v2 header is 10 bytes
+        local payload = msg:sub(12)    -- Payload starts at 11th byte for MAVLink v2
+
+        local decoded_msg = decode_named_value_float(payload)
+        if decoded_msg then
+            local name = bytes_to_string(decoded_msg.name)
+            local value = decoded_msg.value
+            --gcs:send_text(6, string.format("Received NAMED_VALUE_FLOAT: %s = %f", name, value))
+            gcs:send_named_float(name, value)
+        end
+    end
+    return update, 100
+end
+
+return update()