diff --git a/app/controllers/readings_controller.rb b/app/controllers/readings_controller.rb
index f196e82..755d4dc 100644
--- a/app/controllers/readings_controller.rb
+++ b/app/controllers/readings_controller.rb
@@ -21,7 +21,7 @@ class ReadingsController < ActionController::API
       params[:arduinos]&.reject do |a|
         a[:id].blank? || a[:sensores].empty?
       end&.each do |a|
-        arduino = reading.arduinos.build local_id: a[:id], raspberry: raspberry
+        arduino = reading.arduinos.find_or_initialize_by(local_id: a[:id], raspberry: raspberry)
 
         a[:sensores].each do |s|
           arduino.sensors.build(sensor_params s)