Desktop Elevator for Autistic Kids

This Instructable describes a desktop elevator model I built several years ago for a friend's son with Autism. He has been in love with elevators for years and encourages his mom to ride elevators whenever possible at a mall or in office buildings. I thought it would be a fun project to make a desktop sized elevator that he could run any time he wanted without having to make a trip to the mall.

In the process of researching elevators I learned there is a whole community of Autistic elevator lovers on YouTube. Elevators provide a multi-sensory experience that make them appealing to people with Autism. Mechanical objects like trains, busses, and elevators with sounds, lights, and movement have a common fixation for kids with Autism. Pushing the buttons, the lights, the doors moving closed, feeling of the motion, and the sounds of the mechanism moving, all make elevators attractive to these kids.

The most well-known YouTube elevator channel is by Andrew Reams, whose YouTube channel name is DieselDucy. He has over 25 thousand subscribers and 82 million views! I also found a wide range of attempts to build small versions of operational elevators, but they ranged from too big, to too simple.

My design is a three floor elevator, with a simplified door, that could be called to any floor by pushing buttons on each floor. The scale was desktop sized, so that the elevator cab was about right for placing Lego characters inside. It turned out to be a complicated project using one Arduino as the controller, servo motors to open and close the doors, and a stepper motor to drive a tall lead screw to raise and lower the cab. Mechanically, it was built using T-Slot framing rails to build the framework that had channels for foam core doors to easily slide.

Three years later, I did an upgrade and added an LCD screen and sounds to increase the level of reality. This is described at the end. In the future I may extend the capability beyond entertainment, to possibilities for teaching about numbers, sequences, etc. 

Because of the complexity of this project, the goal of this Instructable is to describe the overall design to motivate other Maker/builders to construct their own version. It is not to provide a construction blueprint and software code to make an exact copy. I’ve included some time-saving trial and error details that I hope will help make your project a success. But this is not a simple project.

Arduino microprocessor (any version)

8 - T-Slot 80/20 Aluminum Extrusion Frames (Amazon or McMaster-Carr). Standard pre-cut lengths of T-slot rails are used. The basic frame is made from eight 12" lengths to make a square front and square back. Those squares are connected by four 6" lengths to complete the frame. One more 12 inch length is used in the back to hold the elevator lead screw.

In addition to the T-slot rails, corner connecting hardware is used to connect the rails, including

1- Nema 17, 300mm Linear Stepper Motor. This is a common stepper part used in CNC and 3D printers. If you search you can find one attached to guide rails. Try searching for, "300mm Long Ball Screw Linear Guide Rail + Nema17 42 Stepper Motor. This will require customization to add three micro-switches and the cab housing.

3 - Stepper motors

3 - Lighted push button switches for floor requests

3 - Micro-switches to detect when the elevator is at the right floor

1 - 5V power supply to augment the Arduino power for the servos and stepper

Foam core used for the doors and elevator cab

Here is a link to a YouTube demonstration of the first generation elevator. The picture is of the second generation which has significant improvements to the front to allow sliding in photos of stores on the three levels.

The outside framework is made from T-Slot rails. It is assembled from pre-cut lengths. This is an ideal choice because it provides a track for the doors to slide back and forth. The first picture shows a good view of the stepper driven leads screw that lifts the elevator cab. You can also see the cab on the first floor. This is just made from foam core and hot glued together. It is carried up/down by the lead screw. This also shows the three micro switches mounted on the T-Slot to detect when the elevator is in the right position for each floor. You can also see the doors with connecting links to the three servo motors, one on each floor. The top is covered with PVC sheet cut to size and a handle added to make it convenient for carrying. Rubber bumpers are on the bottom corners to make sure it does not scratch mom's furniture.

Each door is just a square cut from foam core that will slide back and forth in the T-slot track. The rear view in the first pic shows a servo "control horn" epoxied to the back of each door. These are common hardware you can get at Hobby Shops used in radio controlled models. The horns are connected to the servo by a linkage made from bent piano wire, also available at hobby shops. The linkage length and positioning of the servos will have to be determined by trial and error. This is done by manually rotating the servo through their full 180 degree motion to see how far forward and back they move, then bending the linkage to adjust the swing.

This picture shows how the three servos are mounted to two aluminum bars about 1/8" thick and the height of the frame. One bar on each side of the servos.

These pics show a side and back view of the cab attached to the stepper lead screw assembly and a front view looking into the cab. The cab is a hollow cube open on the front, made of foam core hot glued together.

There is a white light LED on the top to illuminate the inside when the door is open. The inside back wall is decorated with a picture taken looking into a real elevator cab, printed on paper, cut and pasted onto the back wall. The floor and side walls are covered with decorative paper that looks like floor tile and paper.

A read view is shown of the three floor selection buttons. These are large buttons that light when pressed, so they take 3 wires each. Nothing special about the buttons, but these happened to be actual elevator buttons.

A listing of pseudo code for the Arduino software. While the basic organization is fairly logical, the actual Arduino code gets more lengthy with lots of calls to displays, lights, sensing switch states, etc. It does not require any specialized programming, just lots of details.

A Fritz diagram of the hardware connections is shown. It is not overly complicated, just lots of wires to make it all work.