I have a hallway, 1.2m wide, with 5 automatic doors.
Walking through the hallway – with conventional detectors – opens one door after the other
I thought of using ultrasound, but the dogs don’t like it.
I thought about laser beams, but do not know exactly how they work practically; e.g. single beam from ceiling to floor; but how would it sense being interrupted?
I could work something into the door blades, like some proximity sensor (what kind?).
Maybe infra-red? I am thinking that a human needs to be in the vicinity of 200mm for the sensor to react.
Or even (non-)touch panels, which could react by touch or 20mm distance of a hand, elbow, etc…
It should be unobtrusive… almost unnoticeable…
It should work without touch, and hook into an Arduino; this part I have covered.
My post demonstrates the complexities of operating automated doors on confined spaces.
… such as a hallway, where doors are opposite each other; or at the end, where three doors are located – one in each direction.
Also, the automated door:
does not only open or close; it may be ‘told’ to stay open.
needs to be operated from both sides
in case of a door-blade-central touch/near field panel, it disappears in a wall cavity, unable to be reached to further operate the door (at least on the inside of the room)
Is the wall switch the only practical solution; one I was hoping to avoid with automation
The situation can be quite complex, e.g.:
How does a small child operate a specific door?
How does any human operate a distinctive door?
If you would have to solve this problem, how would you do it?
… if the constraints are extended to no wireless or radio frequency
Laser sensors are usually installed wall to wall, not ceiling to floor. They work by having a transmitter and a receiver. The transmitter fires the beam across to the receiver and the receiver detects the beam being broken when it no longer sees the beam. This is how the sensors in modern garage door openers (in the US at least) work. NOTE: I think the beam is infrared.
I think the sensors for commercial building door openers work with a simply Infrared PIR mounted to the top of the door. When motion is detected it opens the door.
I think there are some however that work by sensing weight. Have a plate embedded in the floor which triggers the door when it senses weight in front of the door, or senses a change in weight. I’m not sure how feasible that is in a home but it is an idea.
You could set up cameras and use some computer vision to “see” when someone is near the doorway. It might add some security (thought the creepy factor goes up too).
You could have them open based on sound a la Airplane 2.
This is all going to be managed in rules with some way to have the users tell the rules to keep the door open (a button?)
You will need sensors (what ever ones chose) on both sides of the door no matter the solution.
Check that a door like that in a hallway meets fire code. Similarly, I’d also be cautious about any door that can’t be manually opened for safety and fire code reasons as well. Even those automatic doors at the store can be manually opened in an emergency.
Retro reflective sensors have the emitter and receiver in one housing, they just use a reflector on the other side to bounce the beam back. Distance isn’t as good as a through beam sensor, but more than enough for a door.
You could place the sensor at foot/knee/hip height within the door frame so a simple bodily gesture would break the beam and open the door. Or, tinker with things a little and place the sensor on the opposite wall to the door, and the reflector on the door itself. You would need to use a timer so if the beam is broken for a period longer than that needed for someone to walk past it triggers the door opening action.
Or, perhaps the laser is overkill, and a directional PIR would suffice. You could test putting a small shroud around the sensor to direct it’s field of vision to that only directly in front of the door. This would require some trial and error perhaps. And may fail if someone isn’t standing ‘just right’
For what purpose do the doors need to open automatically? Hygeine? Ease of use (because handles are difficult when carrying stuff)?
Assisted living; we are turning 60, with my wife potentially needing a wheelchair in a few years.
I am currently building, hence adding things which aid autonomy.
Or give a few more years and I may need a walker… do I want to take hands off to open doors?
hahaha you are funny. Well, we live off the battery, and have the grid as backup. I would not expect both to be on fire – however, I mentioned it, meaning, while it can be opened manually, it is also on (permanent) UPS power as a safety measure… and can have its own too
This is (internally) quite an interesting discussion. goals, core functions and exceptions get mixed up quite a bit… lots of fun.
Also with respect to switches… if you need switches for everything, we end up like in the photo with 50 switches on one wall section
Maybe I am too advanced
Think first computers, and the question: why would have a domestic home ever have a computer.
Kirk to Enterprise: touching a sort of radio device…
Computer: what is this and that?
Doors that do open – for decades now.
Cars that self-drive
… all unthinkable and greeted with reservations…
Many of the reservations stem for the unreliability and usability I’ve seen with my own setup and others. There is a whole lot of things that are possible in home automation but sadly there isn’t much that has a rock steady years long reliability. There isn’t a single part of my system that I haven’t had to tinker with or trouble shoot in the past six months. That is fine and acceptable when it comes to non-safety related things like turning on and off a lamp or for something for which there is a manual backup way to control it. But for safety related things light whole house lighting, doors, etc. I personally do not trust the long term reliability of these technologies enough yet.
So it has less to do with can you make it work than it has to do with, in the utmost emergency (e.g. house is on fire, home invasion, tornado, blizzard, etc.) is my house more or less safe than it would be otherwise. I just can’t say yet that it would be more safe if it were 100% computer controlled.
Well, I understand ‘security people’ … … and hence, understand where you are coming from.
I have been designing commercial solutions all my life, and so will be this home automation system.
I already have two systems: dev & test, and production.
As far as the doors go; they are a commercial system, except I am planning on building the control myself; for two reasons: 1. the commercial sensor puts the price point close to $1,000, and 2. given my space constraints, I need something more accurate (even a combination of multiple sensors).
Well, I have built quite a few electronic devices, decades ago, which still work today. See, I am not building in obsolescence as it is done by manufacturers for decades now.
Also, I would argue, why a ‘new technology door’ has to behave differently to an ‘old technology’ door; e.g. why it should be possible to open an electronic door in case of an emergency, which is not a requirement of a traditional door – it will be broken down by the emergency service.
So, the unreliability you have experienced does not stem from the technology per se, but from its unreliable (composition / design) implementation.
This is actually quite a nice find… I like the ‘round’ shape of it… then on second thought, I need something where I can select the sensitivity via software… but still, thanks.
Actually it is a requirement of a traditional door. If the door has a lock, according to the building and fire codes where I am, it must be unlockable from outside the door. Deadbolts, chains, and the like that can only be unlocked from one side of the door are not allowed on interior doors. Deadbolts that can only be unlocked with a key are not allowed on interior doors. An electronic door that can’t be opened if there is no power (perhaps the fire damaged UPS or the motor was damaged or the computer that controls it is down) would be like an interior door with a dead bolt.
And in case of a fire the door knob has almost no chance of failure in most emergency situations. It certainly has less likelihood of failure than a sensor, motor, or computer, let alone all three combined.
And keep in mind I’m mainly concerned about getting out of the house yourself in an emergency. Emergency responders are indeed going to be breaking down locked interior doors with kicks and an ax and are not going to bother with unlocking doors. But by that point it is likely too late for you. The number one cause of death in a house fire is smoke inhalation, not burns.
Be that as it may, I’ve not seen enough reliability from individual military grade or space grade electronics to trust my life to them (I work in this industry). That is why most of these systems have triple and sometimes quadruple backups and use fault tolerant designs and algorithms (e.g. Byzantine Generals) for life critical systems. Doing the same for home automation is simply not feasible.
Given my experience I would say that indeed the technology is A source of unreliability.