diff --git a/app/controllers/readings_controller.rb b/app/controllers/readings_controller.rb
index 8e1b877..6471d30 100644
--- a/app/controllers/readings_controller.rb
+++ b/app/controllers/readings_controller.rb
@@ -15,7 +15,7 @@ class ReadingsController < ActionController::API
       reading = raspberry.readings.build reading_params
       reading.id = params[:transaction_uuid]
       # TODO: Verificar firma
-      reading.signature = headers[:'X-Signature']
+      reading.signature = request.headers[:'X-Signature']
 
       params[:arduinos]&.each do |a|
         arduino = reading.arduinos.build local_id: a[:id], raspberry: raspberry