Dog elevator/stairlift

[gigidk13]

Hello! I am an absolute beginner to everything Arduino, circuitry, engineering, carpentry - you name it. I'd like to build my dachshund a lift/elevator up the stairs to protect her back and save her from injury. I'm in the research stage of my project and am looking for advice on its feasibility as well as some guidance on what terms I should be using when I'm searching for parts (I'm a little lost). Any jumping points are appreciated!

Here is Pixel the weenie dog:



I would like to train my pup to use the lift/elevator on her own and I think this is where an Arduino would come in handy. Simplified, I'd like the elevator to work as follows: when my dog enters the elevator, it will sense her weight which will trigger it to move up/down the stairs.  

There are some videos on youtube (https://youtu.be/i3gY8rNpSeM) where they use a winch (that's a new term for me) to pull the elevator up and down. However, my dog is about 12-15 lbs so I'm hoping to build my own winch and power it with a motor controlled by the Arduino (the winches I've found online are heavy-duty, 600lb+!).

Some questions:

• Is what I'm looking to do feasible? Is an Arduino necessary and would it help?
• How to go about finding a motor, any special terms I should be using when researching?
• Any suggestions about how to trigger the elevator? I'm thinking weight - is there such an Arduino sensor that can do this and if so, any suggestions on terms to use for research? Is there a better sensor that's more effective/safe?
• If I use weight or some other sensor, does that mean I'd need an Arduino at both the top and bottom of the stairs? Or can one Arduino be used to sense weight at both ends? I guess I could get away with one arduino at the top but have a very long cable attached to the sensor that self retracts as the elevator moves up and down?

Thanks, everyone for your help and insight! I'm hoping this thread will lead to better research on my end.

[xl97]

My first suggestion to you would be to:

forget about all electronics *(for the most part)

And think about the mechanical portion first.

The box.. the 'lift'.. how does it move up and down along your 'path'?

How long does this need to travel?

In my mind.. you could probably make/fabricate/buy some sort of 'geared rack'  (think rack and pinion).. to mount on-top/under the stair rail?

You would need a matching GEAR that that works with the 'rack'.. that is then secured to the 'box/elevator'.. that move up the hand rail..

** The electronics to keep in my while seeking this part out is:

Where will my electronics go?  You will probably need some sort of STEPPER motor to control the movement..  so you need to think about how the stem/shaft will 'jut out' and connected to the gear it will be controlling.

First and foremost if the mechanical engineering..

if if you just are able to move it up and down by hand, securely... then you can start thinking about the weight/trigger..etc


update:
watched video..  you could the same thing with wire/rope...whatever..  but just an arduino and stepper motor..

[Railroader]

It all sounds like an elevator made for and used by disabled persons. Try and find out how they are built. The mechanics is the hard thing, not the controlling parts. They often use rails fitted to the wall.
A more covnetional rail road track, normally kept upright along the wall, turned down to horizontal when need for transport is the idea i get, here and now.

[Blackfin]

When you're blocking it out, make sure to consider safety: Make sure pupper (or her tail or paws etc) can't get squashed or pinched in it. Think about any part responsible for starting or stopping -- including firmware -- and what hazards might form if that part should fail. Would it start unexpectedly? Would it fail to stop when it should? Is the mechanism and power supply protected against stalling or overload? What additional things could be added to form a level of redundancy?

It's awesome that you're thinking of protecting your wee pup's back and legs and hips but make sure whatever you come up with is redundantly safe for her.

[saildude]

I doubt you need a stepper motor - put limit switches at each end - make the switches/sensors redundant - i.e. you want two switches/sensors so if one fails or goes out of adjustment the lift will still stop and it has an over travel alarm

Just in case you probably should have hard wired e-stop buttons at each end - push to stop and stays in and a reset button

[hammy]

I'd look at maybe buying a secondhand stair lift , easier to install and you'd only have to modify the controls for the dog to use .

Actually if you put a plank down One side of the stairs with rubber matting couldn't he just run up that ?

[PerryBebbington]

I'm probably speaking out of turn here as I am a cat person not a dog person, but why does a puppy need a stair lift? None of my dog loving friends has ever expressed any concern about their dogs being injured going up or down stairs.

[eiriks]

I love the idea, though unless your dog has some underlying disabilities, I have to agree with Perry whether this is really needed. But then again, who cares! It's fun

If you could tell a little bit more about the construction of the staircase where you want to build your dog lift, it would be easier to help with some ideas. Maybe a picture?

[dave-in-nj]

I'm probably speaking out of turn here as I am a cat person not a dog person, but why does a puppy need a stair lift? None of my dog loving friends has ever expressed any concern about their dogs being injured going up or down stairs.

the simple answer is that because they have a dog and not a cat !
I too agree that the sled, the rails, the motor and pulleys and such do not need an Arduino.
what you can do is to have a switch, or series of switches, that sense the weight.  14 pounds work, 30 pounds does not.
I would even move the switches to make a front ramp come up, even a small one.  like a D-Day landing craft.
it would train your puppy to sit and wait and not jump out.
and at the top, it could cover any of the extra parts.
I would use a pipe, like electrical conduit as one of the rails so you can have a way to stop the cart from coming away from the rails.  you would not need rollers, just some plastic like a dollar store cutting board.
you are also correct that you do not need a massive motor.  you can get a gear motor for under $20 that would work.  you trade speed for power.  one of those 2,000 pound winches typically might have a power window motor in it, with a lot of gearing.

[gigidk13]

Thanks everyone for your insight and suggestions! I've learned a few new terms (like stepper and gear motor, limit switches...) and have a better game plan in mind on how to go about researching the mechanics. I love the idea of having a front ramp (thanks @dave-in-nj). 

It would be great if I could get away with just a simple ramp for Pixel to run up, but the stairs are long and steep (I think about 45 degrees) which wouldn't work. Weiner dogs aren't very agile (save for running straight, very very fast!). Their short little legs means their spines are quite prone to injury so they shouldn't be going up and down stairs for too long. Not to mention, Pixel is terrified of going headfirst down them! So far we've been carrying her up and down, but it would be nice if she could be more independent and explore the house at her will  

[Railroader]

It ought to be doable in a safe way. A dog is able step over gaps. Gaps could minimize or remove the danger of the dog getting a paw, a leg, trapped. Downwards travel can use gravity, upward travels monitoring f ex the motor force used, ought to be done in a safe way.
I would think of a wall mounted douböe rail, well covered from noses, paws, legs....

[Paul_KD7HB]

My first cousin and her late husband are retired Air Force officers. The late husband was paralized from the waist down. He had a motorized chair-lift installed in their stairs between the basement and the main floor. By looking at your picture, you do not have enough room to install anything on those stairs.

Please go examine the local rules for legal stairs in your location. There are minimum requirements.

Paul

[Railroader]

To lift a "little dog" must call for a lot smaller equipment. Having seen stair lifts made for wheel chairs, being hung on the wall, a small version for a lite weight dog could be no problem.

[dave-in-nj]

If it is mostly about the high step. 
Considder making  locks.
Half the rise and half the depth. About 8 iinches wide.
Then you would have more steps but much easier to manage.