diff --git a/app/mutations/sensor_readings/create.rb b/app/mutations/sensor_readings/create.rb
index 0688f7d7f..56762bca5 100644
--- a/app/mutations/sensor_readings/create.rb
+++ b/app/mutations/sensor_readings/create.rb
@@ -10,13 +10,14 @@ module SensorReadings
     end
 
     optional do
+      time :read_at
       integer :mode,
         in:      CeleryScriptSettingsBag::ALLOWED_PIN_MODES,
         default: CeleryScriptSettingsBag::DIGITAL
     end
 
     def execute
-      SensorReading.create!(inputs)
+      SensorReading.create!(inputs.merge(read_at: read_at || Time.now))
     end
   end
 end
diff --git a/app/serializers/sensor_reading_serializer.rb b/app/serializers/sensor_reading_serializer.rb
index cc19555de..8cc4c0776 100644
--- a/app/serializers/sensor_reading_serializer.rb
+++ b/app/serializers/sensor_reading_serializer.rb
@@ -1,3 +1,10 @@
 class SensorReadingSerializer < ApplicationSerializer
-  attributes :mode, :pin, :value, :x, :y, :z
+  attributes :mode, :pin, :value, :x, :y, :z, :read_at
+  # This is for legacy support reasons.
+  # Very old sensor_readings will have a
+  # read_at value of `nil`, so we pre-populate it
+  # to `created_at` for the convinience of API users.
+  def read_at
+    object.read_at || object.created_at
+  end
 end
diff --git a/db/migrate/20191220010646_add_read_at_to_sensor_readings.rb b/db/migrate/20191220010646_add_read_at_to_sensor_readings.rb
new file mode 100644
index 000000000..040deedce
--- /dev/null
+++ b/db/migrate/20191220010646_add_read_at_to_sensor_readings.rb
@@ -0,0 +1,5 @@
+class AddReadAtToSensorReadings < ActiveRecord::Migration[6.0]
+  def change
+    add_column :sensor_readings, :read_at, :datetime, default: nil
+  end
+end
diff --git a/db/structure.sql b/db/structure.sql
index d988eb0f0..4456e5c10 100644
--- a/db/structure.sql
+++ b/db/structure.sql
@@ -1483,7 +1483,8 @@ CREATE TABLE public.sensor_readings (
     pin integer,
     created_at timestamp without time zone NOT NULL,
     updated_at timestamp without time zone NOT NULL,
-    mode integer DEFAULT 0
+    mode integer DEFAULT 0,
+    read_at timestamp without time zone
 );
 
 
@@ -3444,6 +3445,7 @@ INSERT INTO "schema_migrations" (version) VALUES
 ('20191107170431'),
 ('20191119204916'),
 ('20191203163621'),
-('20191219212755');
+('20191219212755'),
+('20191220010646');
 
 
diff --git a/frontend/__test_support__/fake_state/resources.ts b/frontend/__test_support__/fake_state/resources.ts
index 65681e322..dce3f5cab 100644
--- a/frontend/__test_support__/fake_state/resources.ts
+++ b/frontend/__test_support__/fake_state/resources.ts
@@ -229,6 +229,7 @@ export function fakeSensorReading(): TaggedSensorReading {
   return fakeResource("SensorReading", {
     id: idCounter++,
     created_at: "2018-01-11T20:20:38.362Z",
+    read_at: "2018-01-11T20:20:38.362Z",
     pin: 1,
     value: 0,
     mode: 0,
diff --git a/package.json b/package.json
index d0a829a62..d95ab2685 100644
--- a/package.json
+++ b/package.json
@@ -45,7 +45,7 @@
     "coveralls": "3.0.9",
     "enzyme": "3.10.0",
     "enzyme-adapter-react-16": "1.15.1",
-    "farmbot": "9.0.0-rc1",
+    "farmbot": "9.0.0",
     "i18next": "19.0.2",
     "install": "0.13.0",
     "lodash": "4.17.15",
diff --git a/spec/controllers/api/sensor_readings/controller_spec.rb b/spec/controllers/api/sensor_readings/controller_spec.rb
index 0498b6f05..34d594ff1 100644
--- a/spec/controllers/api/sensor_readings/controller_spec.rb
+++ b/spec/controllers/api/sensor_readings/controller_spec.rb
@@ -7,11 +7,39 @@ describe Api::SensorReadingsController do
     let(:user) { FactoryBot.create(:user) }
     let (:reading) { FactoryBot.create(:sensor_reading, device: user.device) }
 
+    it "sets a default `read_at` value" do
+      sign_in user
+      before = SensorReading.count
+      read_at = Time.now - 5.hours
+      post :create,
+        body: {
+          pin: 13,
+          value: 128,
+          x: nil,
+          y: 1,
+          z: 2,
+          mode: 1
+        }.to_json,
+        params: { format: :json }
+
+      expect(response.status).to eq(200)
+      expect(json[:created_at]).to eq(json[:read_at])
+    end
+
     it "makes a sensor reading" do
       sign_in user
       before = SensorReading.count
+      read_at = Time.now - 5.hours
       post :create,
-        body: { pin: 13, value: 128, x: nil, y: 1, z: 2, mode: 1 }.to_json,
+        body: {
+          pin: 13,
+          value: 128,
+          x: nil,
+          y: 1,
+          z: 2,
+          mode: 1,
+          read_at: read_at
+        }.to_json,
         params: { format: :json }
 
       expect(response.status).to eq(200)
@@ -24,6 +52,7 @@ describe Api::SensorReadingsController do
       expect(json[:z]).to eq(2)
       expect(json[:pin]).to eq(13)
       expect(json[:mode]).to eq(1)
+      expect(read_at.as_json.first(23)).to eq(json[:read_at].first(23))
       expect(before < SensorReading.count).to be_truthy
     end