Spring 2018 3DoT Hexy: Level 1 and Level 2 Requirements

By: Raymundo Lopez-Santiago (Mission, System, and Test)

Verified by: Eduardo De La Cruz (Project Manager and Manufacturing Engineer)

Approved by: Miguel Garcia (Quality Assurance)

Update 04/26/18

After several meetings with the customer, the requirements have been updated to reflect changes. For future reference, follow the format for requirements from the stakeholder’s expectations located here


This blog post covers 3DoT Hexy’s Level 1 and Level 2 Requirements. 3DoT Hexy will follow the stakeholder’s expectations which include mission objectives and mission constraints defined here. Requirements stated in this blog post follow the numbering conventions as: C-xx is used for all common requirements for all projects under The Robot Company. L1: xx is used for all Level 1 requirements specific to 3DoT Hexy. L2: xx is used for all Level 2 system and subsystem requirements specific to 3DoT Hexy.

Level 1 Requirements

Level 1 Program Requirements


In accordance with the spring 2018 final schedule, the project shall be completed by May 8th, 2018 and shall be prepared for a demonstration on the linoleum floor of ECS 316 on May 15th between the hours of 10:15 am – 12:15 pm.


Documentation for the project shall be completed a week prior to the day of demonstration (May 8, 2018).


The robot will be designed to be a toy for people ages 8+.


In order to minimize manufacturing and packaging cost, the robot shall be able to be constructed from subassemblies within 10 minutes.


For simplicity, disassembly of the robot shall be 10 minutes.


The robot will be remotely controlled wirelessly via Bluetooth using the ArxRobot Android or iPhone application.


The robot will need to navigate remotely through a custom-built maze (built by AoSa image), memorize the path it took, and autonomously travel through the path it took.


Video support during autonomous navigation will be provided via the Arxterra control panel.


The robot shall have a live VR feed via the Arxterra control panel.


The robot shall avoid collisions if it encounters other robots while navigating through the maze. This involves detecting the robot, retracing steps back, and moving to a room that allows the other robot to have a safe passage.


For quick production of the prototype, the preliminary project shall be restricted to six hours of total printing time with a 2 hours limit for each single print (2/2/2/ 6 rule).


The robot shall use a v6.43a 3DoT board.


The robot shall demonstrate the capabilities of the 3DoT micro-controller for DIY hobbyists.


The robot shall be designed in such a way that there are no dangling or exposed wires.


The robot shall incorporate 3D printed parts to demonstrate the feasibility of the 3DoT board for 3D printed robots.


For good construction techniques, all moving parts and rotating parts shall use bushings or bearings.

Level 1 Project Requirements


The robot shall use sensors to: detect non-navigable and navigable obstacles (i.e., robots) disrupting their path, for intersection detection, and for either line following or hedge following.


To keep cost down, and keep as a toy aspect, the robot shall use only 2 micro motors to drive the movement of the robot.


The robot shall be designed in a way to cost less than $250.


The robot shall have a custom PCB as platform to build from and will incorporate peripherals for sensors.


The robot shall have a chassis large enough to house a 3×7 cm 3DoT board.


The robot will weigh no more than 450 grams.

Level 2 Requirements



Communication to the robot will be through the BLE Bluetooth module.


The robot shall use a single RCR123A 3.7 V, 650mA rechargeable Li-ion battery to power the 3DoT board, which will power the drivetrain and all attached peripherals.


The robot shall use three Light sensors and three IR LEDs connected to a custom sensor PCB to handle intersection detection and for either line following or hedge following.


The robot shall use a Parallax Ping ultrasonic sensor ((detect other robots) to handle robot avoidance.


The robot shall use 3D printed chassis and legs. This follows from the project level requirement about using 3D printed parts.


The robot will use a cam system identical to that of 3DoT David to drive the movement of the legs while navigating through the maze.


The robot shall use 2 micro guard motors to drive the motion of the robot.


The robot shall incorporate 6 legs in the design of the drivetrain to improve stability while moving, to support its own weight and to mimic the behavior of a spider.


The robot shall have a cover to assist in the wire management and to give it a spider feature.


The robot shall have (2) LEDs acting as eyes of the spider.



The Ultrasonic sensor shall have a range of 10 centimeter to 25 cm to detect and respond accordingly to non-navigable and navigable (i.e., other robots).


The robot shall use PLA or ABS filament in the fabrication of the chassis and legs. This will minimize the mass of the robot, while at the same time being strong enough to hold its weight.


Gears shall have a gear capture system to prevent them from popping (main issue encountered in 3DoT David design). This ensures the cam system will work without fear of popping gears.


The robot shall operate in a tripod form, having three legs (2 outer in one side and middle leg in the other side) to provide stability while moving.


3DoT Hexy follows the program objectives defined by the customer. Several revisions for the Level 1 and Level 2 requirements were made after meeting with the customer and clarifying details on certain topics. A recommendation for future MSTs is to meet with the customer on a frequent basis to clarify any questions regarding customer expectations or mission constraints.


  1. https://www.arxterra.com/spring-2016-3dot-spider-bot-preliminary-research-project/
  2. https://www.arxterra.com/spring-2016-3dot-david-executive-summary/
  3. https://www.arxterra.com/2016-spring-3dot-david-final-project-blog-post/
  4. https://www.iconfinder.com/icons/2736378/comment_feedback_list_management_project_requirement_time_icon#size=256
  5. https://docs.google.com/document/d/1kwObe9HkGBeCjMYAETA5GiChyxhY1o6bpcmhWKbNFv8/edit?ts=5ae8d74b#heading=h.vkkyujysdeay
  6. https://www.arxterra.com/spring-2018-3dot-hexy-preliminary-design-review/