August 2022
Furby Product Teardown: Why Embedded Systems Engineering and Human-Centered Design go Hand-in-Hand
<a href="" target="_self">Rob Rehrig</a>
Rob Rehrig

Senior Electrical Engineer

Furby Product Teardown: Why Embeded Systems Engineering and Human-Centered Design go Hand-in-Hand

Interactive toys have always been a source of design inspiration and intrigue for me as an electrical engineer and human-centered designer. Human-centered design is often associated with disciplines such as service and interaction design, but I find toys to be a great example of how consideration for the end-user should also come from the engineering level.

Why Embedded Systems Engineering and Human-Centered Design go Hand-in-Hand

Take embedded systems design for example. This aspect of design can seem hidden away and not directly connected to the user, but a toy’s interaction points with the user are going to be limited (or broadened) by what’s possible with the embedded hardware and the creativity of the developers designing for it.

Therefore, just like external aspects of a product’s design, embedded systems must be driven by a deep understanding of the target user, the context(s) of use, and what functional and emotional attributes the product must embody for the user, with the added responsibility of keeping the design within the bounds of the underlying hardware.

But what I particularly enjoy about embedded toy designers is that they still don’t let the bounds of the hardware stop them.

They understand the target user so well that they’re able to creatively find ways to distract from limitations or employ techniques that make the end-user perceive more functionality than there really is. It requires a lot of creative engineering to design something deeply interactive and engaging while also maintaining a low build cost.

A great engineering team takes on this responsibility of pairing their human-centered design knowledge with their knowledge of what is/isn’t possible from a hardware level. And this is what we practice here at Sundberg-Ferar as we help clients design and develop effective and engaging products from medical devices, to robotics, to kitchen appliances.

They understand the target user so well that they’re able to creatively find ways to distract from limitations or employ techniques that make the end-user perceive more functionality than there really is.

Furby Product Teardown

One example of a toy that I feel does a great job of conveying human-centered design from the engineering level is the original Furby.

Released in 1998, this toy quickly became a worldwide sensation. Furby is a robotic pet that requires attention and care to develop over time. As a result of creative engineering and a deep understanding of the end-user, Furby seemed to come alive at times, to the level that rumors of new abilities and features started to circulate because it was so interactive. With so much success, history, and lore, Furby seemed like a great place to start for our new series of teardowns. We’ll look at how the Furby was able to achieve such realistic movement, what interactive abilities it did and did not have, and what controls were responsible for all of its liveliness.

All the Furby’s movements are driven by a single, bidirectional brushless DC motor. This motor gives so much life to the toy, articulating the ears, eyes/eyelids, mouth, and the base (allowing the Furby to lean forward). Through a series of uniquely modelled gears, wheels, and levers, the motor’s movement is translated throughout the body. An LED and phototransistor are used to track the motor positions and movement. There are precisely placed slots in one of the base gears that the so that the Furby’s processor is triggered via the photo sensor when the gearing aligns to specific positions. These techniques enable the Furby to perform unique movements such as blinking the eyes without affecting the mouth or ears, all from a single motor, bringing the Furby one step closer to appearing alive.

Movement gives the Furby life, but it’s the wide variety of inputs that makes the Furby feel playful. Five different sensor types make this possible. The most obvious are the tactile touch points, the belly, back, and mouth; back and belly for petting, the mouth for feeding. Another sensor many may remember interacting with is the ball switch; it is used to wake the Furby when you flip it upside down, but it also detects smaller tilt movements. On the Furby’s forehead is a lens, and behind that lens are two different sensors. One is an ambient light sensor so the Furby can react to its environment’s light level. The other sensor is an infrared (IR) photo sensor that is used to communicate with other Furbys; each Furby has an IR LED and sensor pair for sending and receiving low bandwidth data. Lastly, and probably most controversially, is the microphone. Despite the rumors, the microphone was only used for detecting and reacting to ambient sound levels; learning words based on ambient speech was a little too advanced for the Furby.

While we’re on the topic of processing power, the Furby is equipped with two processors; the main processor (SunPlus SPC81A according to the Furby source code) is used for keeping track of the Furby’s state, handling inputs and outputs, and is regarded as the Furby’s “brain”, while the co-processor (Texas Instruments TSP50C04 according to the Furby patent) handles the speech/audio synthesis, and IR communication from other Furbys. As for the Furby’s memory, an EEPROM is used to save the Furby’s age, name, and voice. When the Furby is first unboxed, or reset, the name and voice are randomly selected, and the age starts at zero, but increases slowly over time to unlock more language and interactive skills.

Expand your creative engineering and human-centered design skills

Every time I look under the hood—or should I say under the fur—of the Furby, I’m impressed in new ways by the engineering creativity. The unique design and layout of the gearing and levers gives the toy so much life that is still hard to believe is possible from a single motor. The way the toy uses ambient sensors to detect changes in the surrounding environment, not just relying on tactile interaction, causes Furby to react in more organic ways that add to its whimsical nature. By thoughtfully dedicating electronic resources to the features kids would regard as important, such as adding a processor specifically to handle voice synthesis, the Furby is able to appear more capable and intelligent.

There is a lot more going on with Furby than what we’ve discussed here, so if you’re working on your own engineering project and looking for inspiration on how to better engage the end-user from the low-level design, perform your own Furby teardown and see what you uncover.

Or if you’re looking for creative engineering support for embedded systems or smart and connected product design, reach out to us! We’d love to help you create cleverly engineered, highly engaging products!

Reach out now for a free consultation and see how our creative engineering services can help you realize new possibilities for your product development.


Furby Product Teardown: Why Embedded Systems Engineering and Human-Centered Design go Hand-in-Hand


Rob Rehrig

Senior Electrical Engineer

Rob is part hardware hacker, part creative technologist, and part human-centered designer thriving at the cross-section of engineering and design. Led to engineering by his passion for music, art, and math, Rob has degrees in electrical, computer, and music engineering, and his work experience spans both academia and world-renowned design firms.

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