Smart Home Sensor Hunt

[Roadwarrior82]

Hello, I thought I would post here and see if anyone might be able to give me some help/information on where to look. To start, a little explanation of what I am trying to do. I am going to be installing a 4 post car lift in my garage in order to be able to work on cars in there a little bit more easily. But since my garage isnt massive, I want to create a sort of safety for my garage door opener so that if a car is all the way up the hoist, you cant open the garage door since it would likely hit the car and damage either one or both. So What I was wanting to do is find some sort of light beam sensor or laser sensor that I could mount on my garage door rails and if it see's something in the way, I could use something like IFTT to shut off the plug for the garage door opener(wemo plug). But I have been trying to find sensors or anything that would work for this but havent seemed to have had much luck. So thought I would check here and see if anyone would know.

[IkeaGnome]

I wouldn't call it a "smart home sensor", but why not use these?

https://www.amazon.com/Chamberlain-41A5034-Original-Equipment-Manufacturer/dp/B06ZYDH4WK/ref=sr_1_10?dchild=1&keywords=garage+door+sensor&qid=1627860457&sr=8-10

Just set them at a height that would be blocked by a car and wire them in like the ones that are more than likely already at the bottom of your garage door.

[Roadwarrior82]

That was actually my first thought. But the sensors in the garage door opener only seem to be active when the door is already open and you go to close it. I tried blocking the sensors and it still opens no problem. 

[IkeaGnome]

6 minutes ago, Roadwarrior82 said:

That was actually my first thought. But the sensors in the garage door opener only seem to be active when the door is already open and you go to close it. I tried blocking the sensors and it still opens no problem. 

If you got line of sight ones, couldn't you wire them into the actual door open circuit? 

You could also use a whisker switch. Mount it on the lift. Get a Normally Closed switch. Wire it between the motor and the signal wires for the door button and any receivers for the remotes. Mount it on the lift to where when the lift is up it opens that circuit and you can't tell the door to open or close. 

https://www.amazon.com/Stens-430-362-Delta-Plunger-Switch/dp/B004HSFDQM?ref_=Oct_s9_apbd_orecs_hd_bw_b6GQDYZ&pf_rd_r=FH8S3YPPSG6P3RFJT25C&pf_rd_p=5232c2d4-bca0-5da1-b182-354bacd00ec8&pf_rd_s=merchandised-search-10&pf_rd_t=BROWSE&pf_rd_i=5739467011

https://www.amazon.com/TWTADE-TZ-8108-ME-8108-Choose）Adjustable-Momentary/dp/B07NL6JVCY?ref_=Oct_s9_apbd_obs_hd_bw_b6GQDYZ&pf_rd_r=FH8S3YPPSG6P3RFJT25C&pf_rd_p=e5052765-f9e8-5645-b975-c70f1e769f82&pf_rd_s=merchandised-search-10&pf_rd_t=BROWSE&pf_rd_i=5739467011

 

[Roadwarrior82]

That whisker switch might work. The reason I planned on going direct to the power for the opener is because there is a keyless pad outside plus openers in the cars. And it's honestly those ones I worry the most about. Thanks for the ideas so far, giving me something to work with. 

[artuc]

10 hours ago, Roadwarrior82 said:

... The reason I planned on going direct to the power for the opener is because there is a keyless pad outside plus openers in the cars. And it's honestly those ones I worry the most about...

 

What are the wiring codes and so on like where you are ?

 

Can you do mains wiring or are you willing to pay for it ?

 

The industrial limit switch @IkeaGnome linked, the heavier duty ones could be wired to the mains directly to turn off the door opener (no battery backup on yours right ?), a smaller one can switch a relay on the mains.

 

There may be ways on the door opener, depends on the unit. Commercial ones will often have an e-stop terminal that can stop  the door, some can have open safety sensor connections also. That can all be done on the extra low voltage side without having to touch the mains and is the best in my opinion. Do you have a model/manual for it ?

 

Could go a bit overboard with hoist up indicator, bypass/override or seperate e-stop etc.

 

You do not want run of the mill Smart Home/IoT devices as safety devices, too many points of failure. 

 

There are wireless/RF safety devices but they are purely designed for it.

 

I do suggest if you get a limit switch go with a proper brand name industrial one that is IP rated, they are more reliable, more options and are somewhat serviceable/replaceable. (Omron, Siemens, Honeywell, Telemecanique etc)

 

Different if playing with a microcontroller project but once you've got life or limb or expensive gear on the line it's a no brainer to get something better.

 

 

[Roadwarrior82]

Wiring doesnt bother me and I have an electrician friend who could always look over things, but Im comfortable with the wiring part of things. I talked to the garage door opener company and they dont offer any way to add a second set of sensors to keep the door from going up, at least not on their residential stuff like I have. When it comes to cars, and even home wiring Im good, its stuff like this where I get a bit lost. I see so many videos talking about sensors and raspberry pi's that Im sure there is a way to do this, Im just not sure the best place to start lol.