Microwave

Handicap Accessible Microwave

Summer 2015
Segal summer internship

skills utilized:
+ user observation
+ microcontroller programming
+ PCB design
+ vacuum forming
+ sheet metal fabrication

We set out to construct a microwave for use by the developmentally disabled students of North Center in Chicago. The microwave had to use images for its interface, provide tactile feedback, and require only simple motor functions to use.

 

 

Research

My teammates and I conducted user observation of the students and teachers working with a prototype developed by a previous team in order to pinpoint areas that most needed improvement. We gathered that large pictures, tactile feedback, and simple motor functions would all play a role in making the microwave easier to use.

Taking a leadership role in the design and fabrication of the project, I proposed the idea of a "controller" with large pictorial buttons that could be removed from the microwave to be more accessible to wheelchair-bound students.

My initial sketch
 
 
 

Prototyping

After failed attempts to rewire and actuate a push-button microwave, we made the decision to use a dial-operated microwave. Once my teammate designed and fit gears to the motor and dial, I designed a circuit that used a Teensy LC microcontroller to actuate the dial from single button press inputs. I then learned Eagle PCB software to fit this circuit on a 1.5 inch by 2 inch board (motor and circuit assembly can be seen in the bottom right corner of the microwave in the photo at left).

In order to protect the new components, I designed a stainless steel cover in Solidworks that would use existing fasteners on the microwave, and included a panel from which to hang the “controller.” Finally I vacuum formed a piece of polystyrene into a shell which could contain the buttons’ circuitry while keeping the "controller" light.

 
 
 

Results

Challenges along the way included designing fail-safe and self-calibrating characteristics into the motor control program, as well as ensuring reliability of the system as a whole. We conquered these challenges by stepping back and asking ourselves, “Are we overcomplicating things?” to which the answer was often yes. By remembering the priorities of the design, we could simplify components without sacrificing functionality and intent.

The microwave is currently in daily use by the students at North Center, to the enjoyment of many students.

Fully operational!