Inside an Otis elevator button (with schematic)
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- เผยแพร่เมื่อ 18 เม.ย. 2024
- It's always interesting to take a look at elevator components. Especially Otis components because of their iconic history. This is a fairly standard illuminated halo button that may be used by other elevator manufacturers too.
A search on AliExpress for the keyword br27c will find similar buttons, but they may have different connections than this one. Usually 24V because that's a standard control voltage in industrial applications. I've just ordered a couple to look at.
The electrical configuration of this button is odd, because it has a four pin connector, but only three pins are used. A different style of button has the LEDs and switch on four separate connections.
It does make sense to use 3 wires though, as the switch signal is also 24V in some applications.
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I was a service mechanic for OTIS. There are a dozen or so variations of this button using the the same button mounting design. These had 5 different colors of LEDs. Multiple voltages up to 120 volts. There were also all metal with a center dot of illumination. These variations probably explain why the PCB has open component spaces. The metal buttons had a different switch layout because an led was in the center of the PCB. They are not in the slightest bit water resistant and failed a lot when housekeeping wiped the buttons down. I changed hundreds during covid because the disinfectant sprays killed them better than the germs.
Have they made a revision that handles moisture or cleaning products?
@@ninjamaster3453 why would they do that when they can just sell you more buttons?
Wonderful comment.
There was a point during those times i thought my 3m stainless steel cleaner was leaving yellow residue on the steel, thought it was new formulas or something. Nope it was removing layers of yellow mr clean that were directly sprayed on by day staffers.
Oh the elevator service😄
If it wasn't for the elevator, society would never have gotten off the ground. Thank you, keep working.
Arrange a bunch of these up in a piano keyboard layout, wire them up to MIDI, and use them to make elevator music.
First song to test it has to be 'Girl from Impenama'. Buh buh buh, buh buh budup dedah...
I see what you did there..
Apparently you can run the same frequencies for producing audio as you would into a speaker coil into standard LEDs for a very interesting effect.
@@wobblyboost1582 yes. Search “LED vu meter.”
Early electronic elevator car call and hall controls used tone mudulators like vintage touch tone phones so that they could send many buttons over a single sheilded pair to the control room. Good ears could hear them play when pressed.
When I was a kid in the 80s I remember always being a little excited whenever my grandma would take me to the big department store downtown because the elevator had these very special buttons inside that would illuminate a neon light behind them (real neon, the color was unmistakable and it was too early for them to have been AlGaInP high brightness red LEDs) at the slightest touch without any force being applied at all. I'd never seen anything like that before and it seemed a little bit magical. It must have been capacitively sensing touch the way those touch lamps of the same era did. I've never seen them anywhere else since.
The buttons you describe were probably RCA 2040/TD74 (developed for Otis) or National NL-OA4GA neon thyratrons that were made specifically for this use. Effectively a switch and indicator in one very clever device so there was no need for a separate button and indicator. The thyratron was triggered by body capacitance and once triggered the neon would remain ionized until it was reset by briefly removing the supply voltage. It didn't require any mechanical switch or have any moving parts.
I have some of the tubes used in those exact touch buttons. It was neon which was held just under its strike voltage with a superimposed AC referenced to ground. When you touched the front of the module you capacitively coupled the AC to ground and the increased voltage struck the neon, which then remained latched. A sensitive relay coil in series was then energised.
Capacitive touch switches, which got regulated out of existence fast, and redesigned to require an actual touch instead of proximity. This was because of a building fire, where people, ignoring the instructions to evacuate via the stairs only, used the elevators, and the fire in the elevator lobbies triggered these switches, bringing cars full of people to the floors on fire, and refusing to close the doors or leave the floors. The redesign made them have a temperature sensor in the case, and a lot less sensitive, so that they would not operate above 80C, and also would also need to be touched for a half second to respond, not the hand wave near the original one had. Modern ones use IR diffuse sensors, so you need to reflect the diffuse beam with your hand, and only operate when you are close enough, though retroreflective clothing can operate them at around 3m distance no problem. So no shiny stainless steel insulated panel, but a black IR transparent button instead.
@@SeanBZA 4th floor - clothing and sporting goods, 3rd floor - furniture and white goods, 2nd floor - inescapable fiery hell.
@@SeanBZA Japan still uses those all over the place. Far more reliable and apparently their population is smart enough not to get themselves Tide podded out of existence.
Radio DJ: That was Otis and the Elevators singing "Baby, I had my ups and downs" 🙂
I'm that dickhead who randomly presses the alarm button while in motion 🤫🔔
And next up we have Ahti and the Janitors with "YÖÖÖÖÖTÖN YÖÖÖÖÖÖÖÖÖÖÖÖ."
I just found that album at a garage sale!
I'll let you pass for the good effort.
You get in an elevator and find Steven Spielberg is in there, pressing the buttons...
The 4 pin connection is so you can use a common loom, as some of those buttons have 2 colours on them, so the main dim path is always lit, but pressing the button, and the car accepting the call, lights up the other colour, normally green, brightly, showing the call is registered in the controller. Use a common connector and loom, so that you do not have to supply every kit when doing an install with both a 3 pin and 4 pin cable tail, as those button tails only go to a connector block on the back of the call panel, where they are put into a DIN rail mounted connector, that then interfaces them with a cable that leads to the bottom of car, where they are connected to the trailing cable, or to the under car interface card.
24V because that is common, and inputs are almost always optically isolated, not really for safety, but to simplify interfacing, as your input has both a zener diode, to cut out stray voltage, and also a filter and protection diodes, and draws 10mA through the switches, helping to keep the contacts clean, and 24V is enough to puncture any oxide build up on the switch. Those switches stop working only when they fall to pieces in this application, contacts are always cleaned by the tiny arc on closing. PLC side the optocoupler transistor has a pull up resistor and then to the MCU input, now a safe voltage immune to whatever is on the input.
The amount of fun that could be had with that button is worth buying it.
A random button that does nothing, a sign above the button saying " Do not press " and when pressed it makes a fart sound and so much more. 😆
Nice idea, hook up a little electronic circuit which gives people a little zap when they press it as punishment.
And maybe a counter to see how many have fallen for it without saying a word 😁
@@timhartherz5652 I did the zap thing as a young teen to deter my younger cousins. I wired an ignition coil with a simple 555 timer and a 6v lantern battery to the door knob to my bedroom so it would deliver about a 6mm spark to anyone touching it. It didn't work. Oh, the spark worked. They all thought it was great fun! I had not a moments peace until they left and every subsequent visit they would pester me to set it up so they could play again.
The best elevator sign that I've seen said:- "Overtravel through pit and loft is not dangerous, but not recommended"
@@Sylvan_dB the good old 555 so versatile yet so simple.
Maybe you've should have used 2 lantern batteries giving 12V which is what the coil probably was designed for😉
@@rambo1152 On a paternoster or a regular elevator though ?
I have deja vu... and a quick search confirms that Clive did make a video on an Otis illuminated button in 2017, looks the same from the front but has a far more robust construction with a bigger switch inside.
...can't believe that was almost 7 years ago now.
Everybody on floor 5 of the hotel is using the stairs during this episode.
Lol
But is it a UK or American fifth floor?
Otis Elevators: We won't let you down.
IDK, I think he'd be polite enough to leave a note and the correct pair of wires to cross hanging out.
@@dogwalker666 In some buildings, beyond the (missing) 13th floor, they are the same
The buttons for elevator in the building I work in are also 3-pin and are wired as: "hot" -> switch -> "out" -> LED -> "ground". The controller has a weak pull-down on the "out" wire and senses a button press when it's pulled high via the switch. It then drives the "out" wire high to keep the LED lit. This allows a single wire to be used for both button press sensing and halo lighting.
What causes the tactile switches to fail is to much activation pressure. Pushing the button in squashes the metal spring bit and deforms it over time. If you design your product so they never completely bottom out the switch will last much longer.
I think they do have a depth limit. I just received two clone buttons today and they have a robust physical limit.
It looks like a simple micro switch, same as what's on computer mice. It can be replaced but it requires soldering.
If Clive has taught me anything, it's that there are dozens of manufacturers for any given thing. And just because this button looks similar to the ones we've all seen in elevators across the planet, it doesn't mean that they are at all the same under the hood. 😉
My G'Pa born '22 was an Otis elevator/escalator installer for many years after WW2 then a state inspector until he retired. I have all sorts of old Otis-related related 'memorabilia' around the house. This would make a cool brooch if it lit.
I have fond memories of operating the old 'Crash-Gate' lifts in the offices my Grandparents were Care-Takers of in Queen Street, Glasgow, Clive. I was quite good at timing the lifts stopping at each floor. Fascinating direction for technology to take and thanks for the post. Cheers!
When I was in high school, Murray Hill Bell Labs had Otis elevators with wonderful touch sensitive buttons with neon lights behind. In messing around with them, I found out that they were either heat or moisture sensitive because you could set them off with your breath.
The neon was part of the operation. It was powered at just below its strike voltage with ground referenced AC superimposed on the DC. When you capacitively coupled to the neon tube it struck and latched on, also powering a low current relay.
Always cracks me up I use a lift and a nice sexy voice says "Going down" when I press the button.
When I was a kid there were square, neon-lamp-illuminated buttons with no moving parts; the metallic square in the center was either a heat or capacitive sensor. I played around with them as much as adults would let me, and the sensor would detect a finger even if not quite touching. Short life on those NE-x lamps tho.
Something about elevator buttons is warm and comforting...just me or yeah?
Maybe it's because when we were very young, just tall enough to reach, it was our job to press the button. It made us feel grown up and important . Later we aspired to pushing more buttons in the hi-tech future that awaited us. Nobody told us that those buttons would be arranged in a typewriter-style keyboard! Men didn't type, only girls typed.
I miss the old elevator buttons that were warm to the touch
A very nice button...might have to pick up some of them for a small project I'm starting soon.
I recommend the "vandal proof" model. It's got a single LED visible in the middle of the button and is much more robust.
"Cheapie tactile switch" was made in France by the look of it, so perhaps not so cheap. "Better" is a different question.
Good catch. They are almost certainly made by Telemecanique, now part of Schneider. They've long been leaders in industrial switch components. FWIW I think Schurter makes the nicest commercial/industrial pushbutton switches. I've never tried to do a teardown of the ones I've bought (they ain't cheap), but I think Clive would have a harder time getting them taken apart.
The Weatherspoons by Glasgow Central still has its original elevator with well used brass buttons and its lattice sliding gate but it's fronted by a modern door on each floor.
I think that might be a birdcage style lift.
very simple design, what actually is impressive is the engineering. Super rigid and long lasting.
It may be just me - and if I am being honest, I really think that it is just me surmising these things, but this is one of the most informative comment sections on the platform - at a minimum for this video directly. Buttons are fascinating to me. To drill in closer - neon buttons are of particular interest.
yeah our comments should be categorized and indexed via keywords... smFh
Did you nick the ground level switch? 😂 good one. 😂😂😂
In a moment of double nostalgia I realised the first video I ever watched of yours, was a very old elevator controller with solid core wiring and huge contact switches 8 years ago, was fascinating to see what was basically a dinosaur ancestor of the PCB. From 6 Kg to 6 grams lol. If you can ever get hold of still-serviceable tech like that again I'd love to see it examined, they were used a lot in old power stations, railways and shipping.
Here's to another 8 years of Clive 🍻
I took a pressure washer to that old panel. It came up well and is right next to me right now. I should really mount it to the wall.
@@bigclivedotcom Steampunk shiny brass noodle sculpture. 🤓
I'm still wary of metal elevator buttons after getting hundreds of static shocks in the 90's after walking through long hotel corridors with synthetic carpets and then pressing the metal elevator call button. I always assumed the buttons were earthed in those days.
The LEDs are not lit in normal operation. When pressed, the button sends a control signal to the car controller board that returns voltage to the LED to indicate the button has been pushed.
Always impressed with your Skeeeeematiks
@5:00 Mysterious unused contacts. That's for the "press more often to make the lift come slower" logic circuit.......
TKMax uses blue 💙
Wow you just unlocked a hidden memory of getting zapped by static electricity when pressing the elevator button
Try and Schindler one next. They have to be programmed with a combination of being at the floor and press and hold. Otis pushes are an easy Friday afternoon job to replace 😂
I need to get myself a pair of "twizzers" 😊
The one thing that always triggers my OCD are butons that have the floor number/letter just floating inside the button so they have a tendency to rotate and not be straight. For these buttons would it have really broken the bank to have the insert keys so it can't rotate. Really annoying.
I road a otis elevator before and I honstly loved the button feel
They're so *cute* when they're small!
A switch (with schematic)... 🤯The schematic was just about as fascinating as I anticipated. But still interesting to see the design choices.
Been installing access control on some new Otis elevators recently and they have a CAN bus versions of these buttons now as well that you can change the color of the LEDs. But I think those had 5 pin plugs on the back.
That has its ups and downs!
There is a version of OTIS button where there is LED light in the middle, their called vandal resistant
In case anyone's wondering, these buttons cost about $100 each. It's an absurd price for the simple device, but I suppose a lot of industrial components are priced this way
Lovely video
I have exactly one of these 24v Otis switches sitting on my workbench and was wondering how to hook it up. Thanks!!
That ⭕ is pushing all the right ⭕'s with me. Just saying. And here I thought Otis was the name of the lovable drunk on the Andy Griffith show from the 60's. (US). My memory keeps going UP and DOWN so I'm not absolutely sure. But thank you for another all-around GR8T video. Cheers!
I thought Otis was sitt'n' on the dock of a bay, not ebay.
@@wiseoldfool Oh. I see what you did there Up vote +1 for creativity! Much better than my 'drunken' Otis guess. Thanks for the thought. As I was just 🎶"Sittin' here resting my bones.."🎶
"its a very attractive button..."
Those are the words we want to hear.😉
It's more accurate to say that Otis reinvented the elevator brake at the same time that structural iron and steel frameworks for buildings made it feasible for the first time to build higher than about 10 floors, which was a problem without passenger elevators because 10 floors is LONG way to walk up, to the extent that before this, despite there being a good number of 10 story buildings, the upper floors were always really cheap because getting to them was such a pain that people avoided them unless they were cheap enough to justify the climb. (Structural iron and steel frames would have been switched to regardless of passenger elevators, because they take up less interior space in the buildings than the massive masonry walls that they replaced, so the valuable ground and lower floors above ground would have have more floor space in them to generate rents for the owners.)
That looks like a hall call button, if you get the rest of the circuitry they chain together for each floor with wiring up the hoist way, The buttons in the cab itself would be backlit with the number for the floor. The early buttons used incandescent bulbs and they switched to neon and then LEDs
By spacing out the resistors there is better heat distribution.
24V to the LEDs, I suppose that goes to the same elevator controller built in the 1960's that expects a lamp there lol.
Back when I were but a lad, living in an apartment building with an OTIS elevation cluster, the buttons were capacitive, and the lighting was neon. When I was a teenager, I came into possession of an OTIS service key. Back in the day, all their elevators and escalators came with the same key--a Yale #9 keyed to 24437. I used to rent my key out to my friends so they could "park" elevators between floors to, ahem, have "fun time" with their girlfriends.....
The neon was how the capacitive sensors worked, by nudging it over its strike voltage capacitively.
I bet the unused pin is for a green LED option for the button turning green to signify the elevator command received your request.
Very interesting, and very nice looking
the last unconnected pin is to call the elevator. It's the next step elevator : faulty by design x)
I'm disappointed, no microcontrollers, internet requirements and payed subscription to operate 😂
I wonder why these switches do not employ a magnet and reed switch/hall sensor. They are supposed to get a beating and survive. Our elevators on the local station has a lot of failing buttons.
Given the cost of elevators you'd be surprised at how cheap and nasty some of the components are.
The switches are cheap for that reason, they get a lot of abuse, so cheap and easy to replace. The old ones, like from the 1950's, are repairable and serviceable, but they were also expensive. If you pay Otis and the others will supply you with the vandal resistant versions, which do survive well. these are the type generally used in residential buildings, light loads, and generally with cameras, so that breaking the buttons results in your unit getting the bill delivered to them to pay. The older styles did often enough have magnets and reed switches, but also cost 50 times the price, though most had simple open spring brass contact strips with silver alloy button contacts on the ends, which would wipe across each other when pressed, removing the thin oxide layer. Also often operating on 100VAC, or 24 or 48VAC, same as the call lamps, as the call coil and the lamp was in parallel, and closing the button closed a contact on the relay that latched the relay and lamp on. Get to the floor, and the relay was deenergised via a contact on the selector unit being opened.
Considering the level of abuse these buttons see on a regular basis, I was expecting something far more robust! But they seem to have built it exactly as required and it does the job, quite elegant!
Kind of interesting DieselDucy uploaded a video about an Otis elevator in Virginia (with all the buttons behind a panel for some reason) a few hours ago and now you've got one of their buttons.
I'll send you a snippet of the schematic for the elevator buttons on the elevators where I work. These are MCE elevators, but they basically all work the same. One terminal is 24VDC, one terminal is a combination call sense / call latch, and the last terminal is common.
Did you not used to have loads of pinsetter videos?
The Otis elevators from the 90s are very scary to take.
uplifting video
Looks like the table was tortured a bit with the plastic welder ~~~
You can extend the life of the switch if the design h/w limits how far the switch can be depressed, and not relying on the button reaching the end of its travel.
I would expect a quality button from Otis.
that NC connection is there for Otis customers with dungeons that have some odd fetishes and hobbies. lol
Back in 2020 I bought a button that was probably used for calling lifts or for door butons on trains or something, the wiring had me rather confused though as it turned out it had some smarts in it that meant it had to be powered up first before it would actually work as a button, I had intended to use it with a custom-built door intercom/release thing as I'd also got a rather oddly assembled phone that had all sorts of buttons and lamps on it that were not standard, think it may have been used in a community radio station or something but was never 100% sure on that... :P
Older versions have hole in the middle of button, illumination comes from hole in centre. I recommend to watch Otis door control circuit, because it has 4 series relays, which is unusual as other brands use only 2 relays in door control circuit.
I've watched a couple videos on elevators.
It would make a nice doorbell....
Suggestion for a teardown... Aldi have now gone to eink digital price tags at least round our way. black/white/ deep red and they seem to have no external power connection and are programmed wirelessly (store lighting maybe). very self contained and I bet there's a lot of projects those displays can use...
the reason you would use 24v or more for signalling in these large installations is to suppress noise and interference. inputs would usually be optocoupled with tvs and reverse protection.
More for safety reasons. The lower voltage is used in current sinking signal circuitry to reduce noise issues. Most modern elevator user interfaces are below the voltage that can deliver a bad shock in case there is damage that exposes the insides of the panels., or water damage.
I reckon the reason for the ability to have the buttons to light up only when pressed will be for the buttons that don't stay illuminated after thry are pressed, such as the door and alarm buttons. Would make sense to do it in the button rather than trying to get the lift logic to do that
I’m guessing that 24v+ is set at the switch and when depressed it sends a signal to the ecu which then applies 24v+ to the led’s until your floor is reached and 24v+ is removed. Less wires.
You could use these for a stand in, (as opposed to sit down), arcade machine....
Elevator Simulator.
When I first saw the schematic I guessed the power would be on the switch side and the sense and LED latch would be the center contact. But I guess it could ground the LEDs to signal the call instead. I'm curious now which way it works.
I'm assuming the physical button must bottom out on the bezel (limited travel) or else the first ham fisted person in the elevator would render that tactile switch useless.
Did Clive ever do a teardown of an Otis touch sensitive elevator button (2040 thyratron), or was it someone else?
Now THAT was a button!
Bad form to reply to ones own post, but I've just seen an exchange further down about these, including a contribution from Clive.
I'm guessing the LED- must be switched or else the button would be illuminated at all times. I think the the switch is used to tell the controller the button has been pushed and then the controller connects the LED- to light the button (if the elevator is in service).
Please Big Clive, do a video on how bad capacitors affect the function and output of a power supply or circuit
Suppressed the LEDs dont change colour, but I guess the indicator is in the panel to let you know the lift is coming. Nice red ring 😃 Interesting button 2x👍
It's there to tell you the call is latched, ie the elevator knows about your call and in the hope that the button pusher stops pushing the button because it's actually rather flimsy. Interestingly, there is another colour - green. Red is the UP button, green is the DOWN button, or the other way around - I can never remember...
Interesting switch choice.They usual have 100,000 cycles and tend to get bouncy towards the end.
Since elevators have to be serviced in regular intervals i guess it does not matter. XD
Maybe some have a lighted number in the middle? Or, if it is a button used to request the elevator, it might have an up/down arrow.
The tactile switch, made in France is probably by Apem, a long established French manufacturer.
Now I'm wondering if they sell those big LED displays that show the level that the elevator is on and go ding when it arrives. If they do, I'm guessing it would cost a lot more than the button.
I had to replace those tact switches in the controller for a diesel heater. It's worth noting that the dimension for "button height" in the listings is the height of the whole thing, not the actual operating rod - they come in various heights which is obviously critical if they are being operated by something else.
Such a jolly, candy-like button!
When you press it, does it take you to the dock of the bay?
OTIS Elevator has a one story building on Lancaster road in Ottawa, Ontario, Canada - which of course does not inspire confidence!
Aha! There is a floor in your argument... 🤣
Never knew there was so much to them thanks Clive 😊
So much simpler than the KONE equivalent that is over engineered to say the least. Theirs have a chip on board that has to be coded to the lift motherboard for it to operate. (And yup, you guessed it, only KONE engineers can code them)
Now do a video reversing an entire otis gen2 controller!! :P
Wait, so the door close placebo button actually does something?!
Sometimes. It can be programmed.
I found that in most elevators I've used, the door close button will close the doors, but only after a preprogrammed delay. So it won't help make it close faster after you initially hop in, but if someone holds the door open longer than the minimum open time, it will close it immediately.
I still can't figure out why the Otis elevator in my apartment building with a front and rear door has two door close buttons, with one like < | > and one like > | < though... Only one or the other door ever can open at a time.
Otis used to make these amazing buttons that just lit from touch. There was nothing to press. I understand they quit for ADA reasons, but they were in my Dad's office building growing up and since we went back to buttons, I feel like we've regressed.
They were capacitor sensors based on neon. The reason they were discontinued was because they called the elevator to a floor that was on fire due to air ionisation.
Can you do one for kone lifts
Could the unpopulated centre LED positions be used for e.g. illuminating a floor number?
First time I've seen electronic components made in France, or at least just marked France by the manufacturer.
Very interesting! I feel like 9/10 Otis lifts use these buttons and I'm a bit sick of seeing them aha. Great video though!
These buttons ring of dingy hotels and college dorm rooms, but maybe that says more about me than the button
But Clive, does it understand when you say Eleven?
Mr. Otis invented the freefall-brake for elevators. That was one pre-condition for designing and building skyscrapers at all. 😉
Not really. The traction sheave was more important, because it operates without drums to roll the ropes onto. The "all safe, gentlemen" crap is Otis marketing.
@@dougerrohmer I disagree. The sheave is no doubt technically important, but the advertised safety feature is what made it socially acceptable to ask the general public to use these lifts. Hence the still remembered demonstration where Mr O himself was in a lift when the ropes were deliberately cut.
It was socially acceptable to expect miners to use lifts before they had the fail safe features, but not the nice middle class folk who were expected to work in offices in the skyscrapers -- and certainly not the stinking rich in the penthouses suite at the top.
You could call that marketing, but I call it health and safety, dating back to the days when manufacturers still had a conscience about customer welfare.
Just like on the railways the driver's dead man's handle was more than just a marketing gimmick: and likewise all the aviation safety innovations after every crash, and after some near misses. It's not good for business to get known for killing your customers (unless you sell tobacco, of course).
And naturally there are multiple ways that the safety could have been achieved, just as there were no doubt other ways to store the ropes without rolling them onto a drum. Otis invented the first patented versions of both, and it's no wonder that it's the safety one that the general public remember
@@trueriver1950 There is no way to store the ropes on a drum, if we're talking high rise buildings. There is a way to live without safety gear, which is to have a safety factor of 8 on multiple ropes. And don't gimme that "corporate responsibility" thing for the early 20th century - how long did it take to invent safety belts in cars?