more making the hardware stuff actually work...
diff --git a/aos/crio/hardware/digital_source.h b/aos/crio/hardware/digital_source.h
index 52a50ba..9980bd0 100644
--- a/aos/crio/hardware/digital_source.h
+++ b/aos/crio/hardware/digital_source.h
@@ -52,8 +52,8 @@
   virtual ::DigitalSource *source() const { return output_.get(); }
 
  private:
-  // Might be NULL.
-  const ::std::unique_ptr< ::AnalogTrigger> trigger_;
+  const ::std::unique_ptr< ::AnalogTrigger> trigger_holder_;
+
   const ::std::unique_ptr< ::AnalogTriggerOutput> output_;
 };