diff --git a/app/controllers/readings_controller.rb b/app/controllers/readings_controller.rb
index 44e53b8..058d701 100644
--- a/app/controllers/readings_controller.rb
+++ b/app/controllers/readings_controller.rb
@@ -21,10 +21,10 @@ class ReadingsController < ActionController::API
       params[:arduinos]&.reject do |a|
         a[:id].blank? || a[:sensores].empty?
       end&.each do |a|
-        arduino = reading.arduinos.find_or_initialize_by(local_id: a[:id])
+        arduino = raspberry.arduinos.find_or_initialize_by(local_id: a[:id])
 
         a[:sensores].each do |s|
-          arduino.sensors.build(sensor_params s)
+          arduino.sensors.build(reading: reading, **sensor_params(s))
         end
       end
 
diff --git a/app/models/arduino.rb b/app/models/arduino.rb
index 29046d3..73093bd 100644
--- a/app/models/arduino.rb
+++ b/app/models/arduino.rb
@@ -2,7 +2,6 @@
 
 class Arduino < ApplicationRecord
   belongs_to :raspberry
-  belongs_to :reading
   has_many :sensors
 
   validates_presence_of :local_id
diff --git a/app/models/reading.rb b/app/models/reading.rb
index addf084..3ed53ea 100644
--- a/app/models/reading.rb
+++ b/app/models/reading.rb
@@ -2,8 +2,7 @@
 
 class Reading < ApplicationRecord
   belongs_to :raspberry
-  has_many :arduinos
-  has_many :sensors, through: :arduinos
+  has_many :sensors
 
   # @param :public_key [SSHData::PublicKey]
   def verify(public_key)
diff --git a/db/migrate/20220611174308_remove_reading_to_arduino_association.rb b/db/migrate/20220611174308_remove_reading_to_arduino_association.rb
new file mode 100644
index 0000000..69f489d
--- /dev/null
+++ b/db/migrate/20220611174308_remove_reading_to_arduino_association.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+# XXX: La migración que deduplicaba Arduinos pierde la relación entre
+# lectura y sensado.
+class RemoveReadingToArduinoAssociation < ActiveRecord::Migration[6.1]
+  def change
+    add_belongs_to :sensors, :reading, index: true
+    remove_belongs_to :arduinos, :reading, index: true
+  end
+end