Instruction: Given a question and the related document, predict if the question is answerable based on the information provided in the document. Output only yes or no.

Input:
Question: How does it determine the state of the door?  Is it a beam sensor, switch lever, or just a tilt sensor?
Document: Installs easily in minutes and works perfectly. Green light on remote monitor shows when garage door is closed and red light shows when door is open. Change in door position from the vertical when door is opening is sensed by simple internal switch in the sensor. Very reliable so far. Cannot think of any negatives at all.
She opened the inside door to check and the garage door was open. I tapped on the sensor to try to close the switch, but it wouldn't turn to flashing red. Next time closing and opening the door it worked fine, and has worked fine since then. It sort of defeats the purpose if you can't trust it and have to open the door to check for certain.
Initially I thought the sensor is magnet based, like the one used in window alarm sensors. But in fact this is sensor is mechanical, and indicates open/close according to its physical tilt position: when it is vertical, it means "closed". As the door rolls up the sensor soon flips to become horizontal, with its back pointing and parallel to the ceiling.
I have left open the garage door a couple of times after I left home for work. And I found my neighbors left open theirs even late in the night. That's why I decided to search for a garage door monitor.Among all the sensing method available in the market, this tilt sensor is most robust and does not affect by installation dimensional tolerance(means easy to install and fail-proof. )It works as claimed. But the design has some more to go.
Tested out the case of out-of-battery. The receiver stays at its last known state, when the battery is transmitter's battery is dead. Thus, if the battery dies while the garage door is down, the receiver will always indicate that the garage door is down, regardless of actual situation.
I don't think my family will appreciate the beep when I leave for work early in the morning. If Skylink (or Chamberlain) reads this, it would be really nice if the beep could be configured to start beeping after the door has been open for 5 minutes. The beep volume can be set to off, low, or high with a switch. It also has a mute feature which you can press if you know the garage door will be open for a while.
The units would be reset once the door is closed again. When opened again, the beeping would again commence for 30~60 seconds. That coupled with a volume switch would be nice. This way one could be possibly awoken in the bedroom should the door open `mysteriously' in the night (i.e. me sneaking in from a long day at `work').Lastly, the receiver units are white and the power transformers are black. Okay. Whatever.
Installation was straight forward and simple; mainly do to the simple design. The transmitter does uses a mechanical type position switch to send signal thus it does need to be fastening securely to door. I found the self-adhesive Velcro strip does a good job however be sure to clean the surface well before applying. I wouldn&#8217;t think it would stick to a wood surface well.
Works well, exactly as advertised. The company could make a model that is inset and wired like a wall switch. Just a wall plate with a red and green light.
Anyway, even if it was due to low battery, it should not send a cheating signal; It should indicate the third state (low battery) by blinking between red and green alternatively (or any other method). Simply it cannot cheat, no matter what, even occasionally.
Answer: yes