diff --git a/app/controllers/readings_controller.rb b/app/controllers/readings_controller.rb
index 103f3f0..c32efab 100644
--- a/app/controllers/readings_controller.rb
+++ b/app/controllers/readings_controller.rb
@@ -21,14 +21,14 @@ class ReadingsController < ActionController::API
       params[:arduinos]&.reject do |a|
         a[:id].blank? || a[:sensores].empty?
       end&.each do |a|
-        arduino = raspberry.arduinos.find_or_initialize_by(local_id: a[:id])
+        arduino = raspberry.arduinos.find_or_create_by(local_id: a[:id])
 
         a[:sensores].each do |s|
-          arduino.sensors.build(reading: reading, **sensor_params(s))
+          arduino.sensors.create(reading: reading, **sensor_params(s))
         end
       end
 
-      if raspberry.save
+      if raspberry.save!
         render plain: reading.id, status: :ok
       else
         head :bad_request
@@ -36,6 +36,8 @@ class ReadingsController < ActionController::API
     end
   rescue ActiveRecord::RecordNotUnique
     render plain: params[:transaction_uuid], status: :ok
+  rescue ActiveRecord::RecordInvalid
+    head :bad_request
   end
 
   private