Fab Terrarium

WS 2018/19, The Media Computing Lab Project

Official Lab Project:
https://hci.rwth-aachen.de/mcp1819

Our code repository can be found at Jaadu

The designed alien is a vital part of the fab-terrarium. It interacts with animals and plants in the terrarium as their emotion depictors. It also interact with the external user of the terrarium using a hand-held device. This device can cause movement of the alien and provide feedback to the user about transferred movement.

We also designed a user evaluation questionnaire for the complete terrarium which is available at: https://goo.gl/forms/JwVNhltjm1XeU8yt2

Let’s talk about the process we incorporated to design alien. The implementation is depicted using a diagram.

Implementation of the Alien

Alien: The body of the alien comprises of 3D printed body structure, 2X LED Matrix for eyes, 2X 3D printed legs (crawling based movement), a RasPi for communicating with Power hand and a 9V battery for the power supply. The eye panel is designed in such a way it provides alienated look for the design.

Alien – Final Design
Movement of alien with emotion depiction.

Power Hand: Power hand is designed using laser cut Plexi glass and LED Strips. It contains bluetooth module for communication with the alien, gyro sensor to detect the hand movement of the user and an arduino nano for sending data for LED strips. The LED strips follows a pattern according to hand-movement. On moving the hand towards left direction, the LEDs will follow serial blinking in right to left manner and vice-versa.

Hand-held device for external users to interact with the Fab-Terrarium.

Alien Specifications: Eyes of alien can depict multiple emotions based on the emotions of the animal/plant in its vicinity. The default emotion is Idle. A variety of emotions are depicted in the following figures.

Emotions depicted by Alien when in vicinity of Animal/Plant.
Alien is Sleeping! Do not Disturb!
Well, I am tired!
Alien in it’s angry look !

Leg Movements of the Alien!

Some short notes:

To implement the robot body, the feedback of the end users (gathered through lab-work) and the project constraints were considered (technical aspects, budget, time, etc.). Having a display for a face was discussed. This would have the advantage of it being easy to add extended screen-based functionality and interaction. However, finally, we opted for LED matrices as those would ensure discernibility and visibility of the displayed emotions, even in brightly lit rooms. White opaque material was used to visually connect the LED matrices.


The key contributions of this work include: a conceptual agile process for designing, evaluating and developing the alien; a computational component for emotion depiction, integrating in terrarium and customized movements with a hand controller. This rapid development of incrementally more complex prototyping and evaluation may benefit other research projects, especially when designing for understudied groups of people, involving new and innovative technology, situated in specific and complex task domains and environments.


As design considerations for a system that would be socially acceptable, we mainly stressed that the robot should be functional. Robot functionality is highly dependent on the target individual. This entails that a high degree of customizability is needed. Every individual needs a different design solution depending on their needs and possible impairments. Generally, people prefer (heuristic evaluation) a somewhat humanoid way of expressing emotions via a face, with individual people’s preferences ranging from abstract to very human-like. More research is needed to determine the acceptability of the current system, as well as research determining if users can recognize the emotions as programmed.

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