LiftLocker Keeps Your Lift Safe from Attacking Garage Doors

Car lifts used to be a tool reserved for professional mechanics. Times are a-changing though. With the advent of reasonably priced four-post hydraulic lifts, more and more shade tree mechanics are joining the five-foot high club. Installing a lift in a home garage creates a few hazards, though. What happens when a family remotely opens the garage door while there is a car up on the lift? Garage door and lifted vehicle will meet – with expensive and/or dangerous results. [Joe Auman] saw this problem coming a mile away. He built the LiftLocker to make sure it never happens to him.

At its core, LiftLocker is a set of switched extension cords. Two cast-aluminum boxes hide the electronics. One box plugs in-line with the lift. The other box plugs in-line with the garage door opener. Each box includes a Sparkfun Redboard Arduino compatible, an RFM22 433 MHz Radio, and a relay. Input comes from a security system magnetic reed-switch. Both boxes are identical in hardware and code.

Operation is simple. One box and reed switch goes on the lift, the other on the garage door. If the lift is going up, its reed switch will open. The lift’s Arduino detects this and commands its RFM22 to send a signal to the other box on the garage door. Upon receiving this signal, the garage door controller will open its relay, disconnecting power to the garage door opener. Communication is two-way, so if the Lift controller doesn’t hear an ACK message from the garage door controller, everything will shut down. Click past the break to see the system in action.

So far the system works. The only problem [Joe] has had is a few missed ACK signals. We’re betting that is due to interference from the high current AC lines running just above the radio module. A bit of shielding inside the box would probably help.

If you really want to limit access to your garage, you could always install a fingerprint sensor-enabled garage door opener. You could even hack an ESP8266 to log all open/close events to Google Drive.

53 thoughts on “LiftLocker Keeps Your Lift Safe from Attacking Garage Doors

    1. Yes, with a four post lift you can jack the car up away from the lift when you need that end’s wheels in the air etc.
      The one in this video has a manual sliding platform to put a jack on to do this that you can spy if you watch for it. My 3.5t Fog brand four post lift has a heavy jacking beam with a inbuilt air powered jack and runs on bearings and rails up the inside of the platform, you roll the jacking beam to where you want to lift and turn the jack valve and up it goes.

      Four post lifts are better for certain jobs, but make others more of a pain. For me, the lift is more stable, they place less stress on the floor mounts and floor structure and I just feel better working on a larger vehicle on it and I can do alignment and steering inspection stuff loaded with turning tables under the front wheels and tighten parts when loaded. Plus some of my vehicles don’t lend themselves to being picked up with two arms at the sides. I know people that will only consider a two post because they use the arm’s to lift body’s off, or unload things from the bed etc, its a bit of a marmite thing I think depending on what you used (you either hate them or you love them).
      It sounds expensive and a pain compared to a simple inspection pit, but a ramp is much safer because you don’t have the gassing/fire while trapped risks inherent with even a well built inspection pit. I have dug one of those too, but only use it when I have to (3.5t+ machines).
      In this case I’d have just swapped the up and over garage door for one that wound onto a bobbin at the top so it didnt interfere with the space mind…

      1. Everything you’ve said I agree with. 2 poster here, given I had to pick one over the other and I work with lighter vehicles (no trucks), just remember your CoG when removing large parts :o)
        I’d also have swapped the door over becasue this now means it’s impossble to store a car on the lift and have another underneath it.
        And as others have said it compromises egress in an emergency, and sometimes it’s just useful to be able to open the door for more room.

      1. I would also agree with a basic hardwired interlock being exactly what you want here. Why such fascination with having things like a cloud based wireless solution that has 5 layers of hardware made by the cheapest vendor possible that requires internet connections, wireless, cell phones and several other things to all work in sync for this to function in between basic safety systems? Just because you *can* or that it technically “works” doesn’t always mean you should or that it is better.

    1. This is the best idea for this sort of system by far, I know sometimes people just want to create a project because they can but sometimes the obvious answer is obvious is because it works best.

    2. I’m glad somebody said it. Too complicated and a single voltage regulator away from complete failure. The only oddball thing in his setup appears to be that he occasionally stores it in the up position.

      Personally I’d go for a key interlock that disables the garage door for as long as the switch is in the locked position. Then it’s up to the mechanic to determine when garage door opening is safe.

  1. Well executed build, looks reasonably professional. Good layout inside the box and wiring doesn’t look like hack job which is way too common in DIY projects (sorry, I hate seeing horrible wiring when it is so easy to do good work like this guy). He explains things pretty good in the video as well which is a plus. Many youtube videos are just show and tell with the assumption that the watcher is as intimately involved in the details of the project as the maker. Nice streetrod!!

    However, it is a heavily unnecessary design and creates a level of confidence in safety that should not exist. It would be much simpler to create a simple mechanical interlock that takes advantage of nearly every garage door opener’s force limit sensors. When I was working on rafter storage setups in my garage, I did the same thing with a properly positioned pair of vise grips on the openers rail. I tried opening the door and when the trolley hit the vise grips, it stopped at flashed the lights indicating an obstruction. Anyhow, as he stated, it’s not like this is going to become a product, so if it works for him, awesome. As a note regarding “wireless interlocks”, there are many, many reasons why not to trust them. He at least tried to build in some dead man features to help with the wireless concern, so have to tip my hat for that effort.

    1. Most garage doors in the US already have a mechanical interlock. A toggle along the slide that disengages the door from the motor in case of power failure. It’s not as sleek but I’m sure a solenoid could could be spliced in it’s place to streamline it.

      There’s also the anti bugler locks that slide into a notch in the rails.

  2. Really neat idea. Would be useful for other interfering machine paths too.The wire antenna is partially shielded with those huge earthed cable hole thingys (technical term) and is probably mis-tuned because of them. For the range he’s in, probably wont matter much. There’s is also the big RF jammer sitting nearby, That mechanical relay will mess things up nicely when it fires/releases, wiping out any packets at that time. Activate relay, send ack.. oops.

    1. I don’t know your finances but you might be able to afford one easier than you think. You can get a “basic” one for about a grand and a half. Provided no living creature goes near it because it is from Horrible Freight, you might be able to maybe get by with it. Says it holds up 6000 lbs.

      I suppose that you could use this and then actually buy some quality made jack stands and then just use this to physically lift the vehicle up.

      Odd that they state that their average time to ship is 4 weeks with a maximum of 17 weeks.

      A proper one that a living being would actually feel somewhat comfortable getting under or just using might set you back a little more but they actually are not *that* expensive if you work on your car much at all beyond the basics and can amortize the cost over 1 – 2 trips to the dealer or 3 – 4 trips to an independent shop for any moderate to advanced work. Plus don’t mind doing the work yourself of course.

    1. I was amused that they went with a solid aluminum enclosure and then not only didn’t install any kind of gasket or seal but then also ruined any kind of watertightness by installing a barrel plug and toggle switch. They are so close too with those nice cord grips.

  3. Great idea- I may just use a 3-way switch in a box to switch two mutually exclusive outlets- one for the door, one for the lift pump. Ten minutes, no code, and dead bang simple.

      1. A closed when depressed switch mounted on a bracket underneath the lowered hoist arm or on the side of it at lowered position that interrupts the circuit for the door will prevent any door to hoist interference issues. A waterproof switch would be a good choice. Or relocate hoist to remove the issue. unlimited budget required though.

      2. But he appears to store it in the up position when he parks a car underneath. If he’s got dodgy code and isn’t willing to use a keyswitch or padlock cover to manual switches to put the system into a car maintenance mode, which only a human can deactivate, he’s heading for a failure of some sort.

  4. I had a similar problem: My compressor is on the same circuit as a radiant heater. Both on will pop the breaker, so I wired them into a SPDT (i.e. “three way”) switch. Want air? Turn off the heat. and vice versa. Sucks to have just 4 kW available in a shop.

    1. Is electric heating your only option in this case? Of course it is easy, but it’s expensive in operation and if it has issues with power availability, I would think about oil, gas (propane) or wood.

      1. or… get a secondary air tank to expand the compressor’s capability and add some kind of sand/water heat resevoir to the heater such that its not such a big deal to trade them off.

  5. Well he put a bypass switch on it so the safety function is null. So now he puts it’s in bypass, forgets he put it in bypass and boom. Seems like the better solution would be a force gauge on the platform and a switch in the lowered position for both the door and the lift. If force and lift switch open then door inoperable. If force and door switch open then lift inoperable. All scenarios covered and no need for a bypass.

    1. But hey, it is your car and/or garage door, so do as you please. If safety of personnel was an issue we would want to be more emphatic (or are we concerned about people working in the garage being hit by pieces of the garage door?

    1. Agreed. One limit switch and a relay is all you need and it would be more fail safe than the Arduino solution posted here. Heck add two more limit switches and you can stop the lift from going too high if the garage door is opened.

  6. Haven’t watched the video yet, but I hope there is another way out of the garage. Fire in the vehicle up on the ramp, and you can’t open the garage door for egress/firefighting.

    1. Yep, pretty much the same situation if there was a fire in a garage with no lift. Because building fires commonly take out the electricity, garage door openers are equipped with manual releases, so the door may be opened without power.

  7. Wow, thanks for the comments! I didn’t expect this to get posted to Hackaday, cool!

    A just a couple clarifications:
    1) I fixed my interference issues with just a simple software update. It works well now.
    2) I went with wireless because the lift is mobile. It has four wheels that allow it to be moved around the garage, including outside. Making LiftLocker wireless makes that whole process less cumbersome. Wired would be a lot simpler for stationary lifts.
    3) Yup, there sure are simpler ways to do this. But like any interlock, it’s a preventative against absent-mindness. It only takes one mistake to ruin a good paint job.
    4) I described this as a safety interlock, which I regret. This is only a property protection interlock. It doesn’t increase or decrease the safety aspect of either device, just limits their movement to prevent damage.

    1. very nicely built in most respects, but regarding #2, if the lift can move outside, presumably the garage door isnt a concern at that point? you could use a hardwired version on the outlet dedicated to plugging the lift in when its in the garage (or any number of other options suggested above) right?

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