convertir valores en enteros antes de procesarlos

app/controllers/readings_controller.rb

@@ -73,7 +73,7 @@ class ReadingsController < ActionController::API
                                       :sample,
                                       :signature,
                                       coordinates: %i[lat lng]).tap do |p|
-                                        p[:timestamp] = Time.at p[:timestamp]
+                                        p[:timestamp] = Time.at p[:timestamp].to_i
                                       rescue TypeError
                                       end
   end