Arrow Electronics and ADI Grant a Child’s Request for a Pet Dragon

Article By : Arrow Electronics Inc.

Working with suppliers and customers, Arrow Electronics helped nonprofit Make-A-Wish Colorado grant a child's wish for a pet dragon and an important new friend.

Like many teenagers, 14-year-old Belle yearned for a pet. But Belle lives with cancer and having a live animal poses health risks. Unwilling to defer her dream, Belle asked Make-A-Wish Colorado to make the impossible possible, in the form of a pet dragon. Arrow collaborated with the nonprofit to grant Belle’s wish, working with suppliers and vendors to build a dynamic, semi-autonomous social robot in the form of the mythical creature Belle imagined.

Sophisticated robotic dragon designed to fulfill child’s dream

Belle has always wanted a pet of her own. Most teenagers want a dog or a cat. However, Belle has been diagnosed with cancer and health considerations discourage her family from owning a live pet. So, she turned her attention toward mystical creatures like the ones portrayed in her favorite novels and movies.

Belle dreamed of training her own dragon.

The nonprofit Make-A-Wish Colorado contacted Arrow Electronics, one of the world’s leading technology solutions providers. Arrow has the engineering expertise and relationships with companies the world over to make this unique companion robot as a corporate social responsibility project.

The project became a team effort to fulfill the wish

Arrow collaborated with several suppliers: Analog Devices Inc. (ADI) provided key electronics and reference designs; Robot innovator Caleb Chung and his team designed and assembled the dragon; Autodesk provided the design software; and ServoCity provided the actuation servos to help the dragon move.

A dragon built with the most advanced technology

The approach was clear: Belle’s dragon would not be a toy. The dragon is designed to provide interactive companionship. Its movements and reactions are meant to motivate, comfort, and encourage Belle at this challenging time in her life.

It has sensors to feel Belle’s touch and respond with fluid movements resembling those of the characters from her favorite dragon stories. Its skin feels reptilian, its expressions change, and it reacts when it perceives a treat. Belle consulted with the Arrow-led team on the dragon’s appearance, haptics, and behaviors.

Arrow engineers brainstormed with Belle about how her dragon should look, feel, sound, move and behave. Robot innovator Caleb Chung and his team handled prototyping while Arrow coordinated with its vast supply network—especially ADI—to provide the electronics and other components needed to make it work. The result is a robot that mimics a live pet, capable of meaningful connection and engagement.


To achieve this sophisticated look and feel, the dragon’s functions incorporate the latest technology. ADI provided crucial electronics, including the servo, controller and power boards, transceivers for internal communication, microphone array, sensors, and other essentials.

A virtual reality program produced by Emerge Studios helps Belle to discover her new pet and explore a mythical world in flight from a dragon’s perspective, adding richness and context to her experience.

“We created a technology for Belle that establishes an emotional connection,” said robot inventor Caleb Chung, who prototyped the dragon with a team of technology fabricators. “Humans need to feel empathy toward things to be more human. We can help that by having creatures that you can love. If we continue this path, we are designing our children’s best friends. There is a lot of social responsibility in that.”

A special experience for Belle, and the prototype for a new generation of companion devices

Belle’s dragon has proven to be so much more than just fulfilling an order. The result of this collaborative effort is not just another toy, but a unique companion technology that demonstrates how technology makes life better now for Belle, and perhaps for many others in the future.

Covered in scaly, reptilian “skin,” Belle’s dragon is about the same size as a small dog and moves fluidly. Thanks to sensors embedded all over her body, it can coo or flap her colorful, illuminated wings in response to Belle’s touch. The dragon changes expressions. She tires if overstimulated and shows displeasure towards certain foods.

Belle’s dragon addresses the isolation and loneliness that is common among children dealing with critical illnesses—concerns magnified by the COVID-19 pandemic. It’s ability to interact provides Belle with critical emotional support, demonstrating how technology can enrich our lives. This platform could be modified to take other forms and programmed to perform other tasks—wakeups, reminders, and communications—to widen its applications and audiences.

How to Build Your Dragon: Arrow created a dynamic social robot to fulfil a Make-A-Wish request

Arrow organized a team of its engineers, technology suppliers, and animatronics developers to build a prototype social robot in the form of a dragon to be Belle’s companion. They consulted with Belle and her sketchbooks for information about the dragon’s size, shape, appearance, movements, and personality.

The team includes robot innovator Caleb Chung, semiconductor supplier Analog Devices, Inc. (ADI), design software provider Autodesk, and Emerge Studios, creator of a magical VR journey so that Belle can explore an entire realm of dragons and meet her dragon with minimal medical risks.

The Dragon: Design overview

Belle’s Dragon incorporates several engineering disciplines. In this article, we will examine the electronics side of the design. The electronics in Belle’s Dragon are split into five separate functional boards: the controller board, two motor boards, the power board, a camera board and an RFID board.

Each board has its own independent controller, but the controller board still has a degree of authority over the other boards. This makes Belle’s Dragon a mix between a centralized and decentralized design. Communication between all the boards is done using a CAN bus, thanks to the ADI LTC2875 transceivers, and the power source of Belle’s Dragon is a collection of rechargeable nickel-metal hydride batteries—an ideal choice, considering the dragon’s portability safety and the use of multiple servo motors for complex movement.


Motor driver boards                                                                                

The dragon utilizes 25 servos and 3 LED channels (RGB) for providing motion and gestures, and all of these are monitored and controlled by the motor board, while the controller board indicates to the motor board what type of movement is required. To start, the motor board communicates with the main controller board using the CAN bus that connects the power, servo and controller boards together. In order for the on-board MCU to work with the CAN bus, a special transceiver is needed (to shift logic levels and condition signals). ADI’s LTC2875 is used in this instance.

Diodes ZXCT1009FTA

To ensure safety and longevity of the dragon, all twenty-five motors are carefully monitored so that if any one motor fails, the system can prevent permanent damage to the rest of the dragon. Each servo has its own built-in temperature sensor to ensure that motors do not overheat while also each having their own current sensor, the ZXCT1009FTA, to ensure each servo draws current within an expected range.

Cypress CY8C4247AZI-M485

Controlling all the motors is the responsibility of the CY8C4247AZI-M485, a mixed-signal microcontroller with programmable digital and analog circuitry. The heart of the CY8C4247AZI-M485 is the 32-bit Arm Cortex M0 CPU, with 128 KB of flash and 16 KB of SRAM. The MCU offers a range of peripherals, including serial communication, PWM, 55 GPIO, capacitive sensor, and an LCD drive. The programmable analog system includes four op amps with a range of different modes, while the programmable digital system includes four programmable logic blocks, with each block having eight macrocells.

Power board

The power board on the dragon provides proper monitoring of the batteries as well as an ultra-low-power mode to do away with the need for a physical on/off slide switch to disconnect power when not in use. The main controller of the power board is another CY8C4247AZI-M485.

The on/off button mechanism utilizes the ADI LTC2950, which is an on/off power button controller. This device works with a wide range of input voltages and has a very low current draw of 6 µA. When a pushbutton is pressed, the device not only debounces the signal but also provides an enable signal for an external power circuit (such as a DC/DC converter). This allows the dragon to have a single pushbutton to turn the unit on and off without the need for a slide switch.


Controller board

The controller board is the brain of the dragon and responsible for reading sensory information, determining the energy levels of the dragon, and for executing the algorithms that change the dragon’s behavior. Central to the controller board lies the CY8CPROTO-062-4343W, a development system for working with the PSoC 62 MCU that integrates a dual-core architecture with a 150-MHz Arm® Cortex® M4 serving as the primary processor and a 100-MHz Arm Cortex M0+ as the secondary processor. Also integrated into the PSoC 62 MCU is 288-KB SRAM, 1-MB flash, RTC, cryptographic hardware accelerators, and a wide range of peripherals, including GPIO, I2S, I2C, USB, and SMIF.

The controller board also connects to the many sensors for environmental awareness, capacitive touch (built into the MCU), multiple contact closure inputs, and an IMU (using the BNO055). Two channels of digital audio with high quality speakers (ADI SSM3582) and preprogramed behaviors provide user feedback via movement and noise that can indicate happiness, energy levels, and needs of the dragon.

Cypress CY8CPROTO-062-4343W

Bosch BNO055


Camera Board

The NXP i.MX RT106F is the center of the camera board and serves as its vision system (the SLN-VIZN-IOT). This MCU-based system allows for easy development for facial-recognition systems utilizing an Arm Cortex-M7 clocked at 600 MHz, 32-KB cache, and 32-KB D-cache.



RFID Board

To provide an ability for the dragon to differentiate between the foods and play-toys we are providing, the Murata LSRFZZHAAA-026 is used as the RFID board in the dragon’s head. This evaluation kit is an HF RFID Reader/Writer with integrated firmware and optimized antenna design for contactless communication 13.56 MHz. With RFID tags embedded in the accessories provided with the dragon, the RFID solution will enable the dragon to recognize the different foods and toys used to play with the dragon.

Belle’s Dragon software

As with any programmable system, the hardware that makes up Belle’s Dragon is only half the story; the software that runs on the main controller is equally important and breathes life into the dragon. While the flowchart that describes the dragon is complex and vast, the concept behind it is simple. The dragon utilizes an energy system that indicates its activity, and the more the dragon is interacted with, the more this energy increases. If this energy becomes too low, the dragon will become tired and move more slowly, as well as perform actions such as sitting and lying down. If this energy level reaches 0, the dragon will fall asleep and wait for sensory activity in the capacitive sensors and IMU.

When the dragon is awake, performing different actions will make it behave differently. For example, if the sensors in the feet are activated, then the dragon expresses ticklish behavior, and if the face-recognition system detects a face, then the dragon performs the “hello” behavior. The dragon also has a range of RFID accessories that use RFID to indicate to the dragon what it has been presented with. For example, food items make the dragon perform chewing actions. The tug toy engages the tug-of-war behavior to play with Belle, and the honeycomb engages the healing behavior, which is needed when the dragon catches a cold.

Development cycle of Belle’s Dragon

The development of Belle’s Dragon has undergone multiple stages of development and prototyping. The prototype of Belle’s Dragon has taken advantage of many different evaluation boards (such as those used by the PSoC 62), which allows engineers to try out various hardware without having to commit to a single fully assembled PCB. It also shows how each different part behaves and if the various sub-circuits are compatible with each other.

Furthermore, the use of ADI evaluation boards such as the EVAL-SSM3582 allow for a reduced development cycle by enabling the testing of various ADI hardware such as the microphone array and audio DSP. The dragon’s development cycle also massively benefited from the wide range of evaluation boards available for the many controllers, sensors, and processors manufactured and produced by companies such as ADI and Cypress.


When the collection of evaluation boards shows that the design can work, engineers then transcribe the various components and ICs used in those boards into PCBs that remove unneeded components, compact the design, and allow mechanical engineers to more closely work with the final electronics. At the same time, engineers from different fields of study work on the various parts of the dragon, including the mechanical and software structure. Belle’s Dragon has taken advantage of a range of different software platforms, including Autodesk, Eagle, Fusion360, and Z-Brush.

Belle’s Dragon project demonstrates how products can be rapidly prototyped in a short space of time and how the use of evaluation boards allow engineers to quickly determine how a system will fit together. The use of the CAN bus allows for designs to be split into individual functional units so that each unit can offload tasks that can then be performed independently of the main controller. The dragon’s use of various sensors and outputs helps to create an interactive toy, while the use of RFID creates a complex interactive system with accessories that can carry their own information.

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