Cognitive Walkthrough

Posted on: Thursday, January 24, 2008

Description of the Prototype

The Sustain-a-Stack is a mini indoor greenhouse used for growing herbs, vegetables and other small plants. Ideally to be located in a living room or a kitchen, this product is targeted for people with interests in the organic food market or in growing their own plants at home but don’t have the space or time to do so.

The physical prototype will include a watering system and LED lights in a box to sustain the plant. Other sensors that will pick up temperature, humidity and water levels will be added later on in the process. The levels that the sensor will detect will transmit to an interface widget on a computer through the Arduino microcomputer. The widget will allow the user to monitor the plant by checking up on its status, viewing the last watering date, water the plant and turn the lights on and off.

Although the widget provides efficient feedback to the user, it will only simulate the desired action since there is still no communication between the interface and the physical box as of now.


Representative Task

At home: The user would approach the Sustain-a-Stack physically and check on its status. Based on how often the plant needs to be watered, the user would push the watering button and the system would spray water on the plant. The lighting system will automatically turn on and off in a cycle but if the user wishes, the lights could also be controlled manually by pressing the light toggle button.

At work/elsewhere: The user would check on the status of the plant by accessing the Sustain-a-Stack widget on his computer. Then he can check the temperature, humidity and water levels. Also shown are the days since the plant has last been watered which then prompts the user to click on the water button on the widget interface. Lights can also be manipulated through this widget.


Actions Needed

Pre-planting -performed everytime user is to plant something new

  • adding soil to fill the bottom of the Sustain-a-Stack
  • planting seedlings within the soil
  • filling water reserve to enable watering through the press of a button or through the widget


  • watering - box/widget
  • turn lighting on and off - box/widget/automated
  • monitor status of the plant in person or through the detected levels on the widget interface - box/widget

Once in a while

  • trimming the plant
  • reaping the harvest of the produce or herbs grown to be consumed



Users + Experience

Our target audience will be people who are interested in the organic food market specifically people who want to grow their own organic food. Typically, our users will be busy, having little time to take tend to their plant. They will have familiarity with using computers to be able the access the widget. They should also have an idea of basic plant care. The user will be able to take care their plants indoors ideally in their living room or kitchen. Having the Sustain-a-Stack is meant to motivate people to grow their own food, promote green living and display the progress they’ve made with their plant in their homes.


Recent Events

Pete, our original prototype plant, died over the Christmas break. RIP. So we got Petunia (Pete-2-nia) :)


We also had to design a poster for the Open House coming up. Andrew will make a better, digital version of it but this is what we have for now. We plan to include a description of the product, our target audience, mission statement and a bit of the processes we went through.poster