S17: Sphero Droid

Grading Criteria

• How well is Software & Hardware Design described?
• How well can this report be used to reproduce this project?
• Code Quality
• Overall Report Quality:
  • Software Block Diagrams
  • Hardware Block Diagrams

    Schematic Quality

  • Quality of technical challenges and solutions adopted.

Sphero Droid

Sphero Droid

Abstract

Robots are revolutionizing almost every industry, primarily in the sectors where human safety is at risk. In hazardous working conditions such as in the mining industry, the lack of knowledge about the geographic nature and the environmental conditions of the mine hinder the rescue operations. Autonomous robots are being employed to improve the plight of mine workers and rescue operators. The robotic vehicle can explore the inaccessible and unworkable mines and disaster-affected areas and send valuable information to the teams to assist in search and rescue operations. But traditional robots could be rendered useless if they are overturned or in terrains having staircases and ledges. Also, there is a possibility of failure of the electrical and mechanical components exposed to the harsh environmental conditions. An autonomous spherical robot is a better option since its shape offers better robustness and rigidity. The spherical robot will enclose all the components within it and will not have any wheels or legs on its exterior. This feature enables it to operate in any hazardous conditions since there will be very less chance for the components to get damaged by the surrounding environment. The spherical design allows it to easily maneuver in different types of terrain, be it stairs or corners, and have no risk of being overturned. These advantages enable the robot for many applications such as exploration and mapping of access routes, surveillance and rescue operations in uncomfortable working conditions.

Objectives & Introduction

The objective of this project is to design an autonomous spherical robot with sensors, Global Positioning System (GPS) module, Bluetooth module and other control units interfaced to the microcontroller, which navigates its way to the destination avoiding obstacles. The temperature and the route followed by the robot can be logged on the SD card. These features enable the robot for many applications such as exploration and mapping of access routes, surveillance, and rescue operations in uncomfortable working conditions.

Sphero Droid front view

Sphero Droid side view

Sphero Droid Internal view

Team Members & Responsibilities

• Ultrasonic Range Finders
  • Sushma Nagaraj
    
  • Shivam Chauhan
    
• Motors
  • DC Motors
    • Virginia Menezes
      
  • Servo Motor
    • Sushma Nagaraj
      
    • Shivam Chauhan
      
• GPS and Temerature Sensor
  • Harshitha Bura
    
• SDCard
  • Harshitha Bura
    
  • Naveen Kumar Bhuthakatanahalli Ramalingaiah
    
• Bluetooth module and Android Aplication
  • Naveen Kumar Bhuthakatanahalli Ramalingaiah
    
• PCB Designing
  • Shivam Chauhan
    

Schedule

Week#	Start Date	End Date	Task	Status	Actual Completion Date
1	3/21	3/27	Requirement analysis and team discussion to order parts. Determine individual tasks and assigning work based on different modules in project	Done	3/29
2	3/28	4/3	Configure and interface the GPS module with the SJOne board Configure and interface individual sensor with SJOne board Interface motors with the SJOne board Upload code on GitLab	Done	4/9
3	4/9	4/18	Designing PCB Team discussions to integrate the design and work on the algorithm Continue work on individual module (Sensors, motors, GPS) working with SJOne board	Done	4/21
4	4/18	4/25	Integrate the different modules Build the sphere with bearings and enclose the components within it	Done	4/28
5	4/25	5/2	Test in different environments and fix bugs based on different issues Team discussion on extra features that can be implemented	Done	5/7
6	5/2	5/9	Testing and Debugging Work on extra features (if any) Work on Project Report on Wiki	In Progress
7	5/9	5/20	Testing and Debugging Project Presentation and update Wiki	Plan
8	5/16	5/23	Complete Wiki Report and Final Demo	Plan

Parts List & Cost

Qty	Description	Manufacturer	Part Number	Cost	Links
1	SJ One Board [1]	Preet	SJ-one	$80	http://www.socialledge.com/sjsu/index.php?title=SJ_One_Board
2	DC Motor	RobotShop	Pololu 4.5V, 80rpm Right Angle Plastic Gear Motor	$4.95	http://www.robotshop.com/en/pololu-80rpm-right-angle-plastic-gear-motor.html
1	Servo Motor	Fry's electronics	Metal Gear Digital Servo Part No. LS-0009AF	$19.99	http://www.frys.com/product/7027281
1	Motor Driver	Fry's electronics	Motor Driver	$9.99	http://www.frys.com/product/8353697
1	GPS Logger	Spark fun Electronics	Venus638FLPx	$59.95	https://www.sparkfun.com/products/10920
1	Bluetooth Module	Amazon.com	HC-05 Bluetooth	$8.49	https://www.amazon.com/dp/B01G9KSAF6?psc=1
3	Ultrasonic sensor	Amazon.com	LV Maxsonar -EZ MB1010	$74.85	https://www.amazon.com/Maxbotix-MB1010-LV-MaxSonar-EZ1-Range-Finder/dp/B00A7YGVJI
1	Antenna GPS Embedded SMA	Spark fun Electronics	VTorch Datasheet	$11.95	https://www.sparkfun.com/products/177
1	PCB components	Amazon.com	(7805, 2 pin SPDT switch, 4004 diode, LD1117, Female pin header, male pin header, USB type B female jack, DC power jack, power supply module)	$72.00	https://www.amazon.com/gp/product/B01LRXIJRY/ref=oh_aui_detailpage_o03_s02?ie=UTF8&psc=1
2	Wheels	Amazon.com	70 x 8mm Black Robot Wheels	$12.00	https://www.amazon.com/gp/product/B00T3MQDHU/ref=oh_aui_detailpage_o08_s00?ie=UTF8&psc=1
2	Bearing	Amazon.com	2 Pcs 22mm Outside Dia Plastic Coated Ball	$7.93	https://www.amazon.com/gp/product/B00HR5SJKE/ref=oh_aui_detailpage_o08_s01?ie=UTF8&psc=1
1	Hollow spherical ball	Amazon.com	Giant Chinchilla Run-About 11-1/2-Inch Exercise Ball	$15.76	https://www.amazon.com/gp/product/B0006IK0LA/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Design and Implementation

System Block diagram

Robot interface

Within the Robot

System State Diagram

State Diagram

Hardware Design

We have four distinct hardware modules used in this project:

• Ultrasonic Range Finders (sensors)
• Motors
• GPS Module
• Bluetooth Module

Ultrasonic Range Finders

Used MB1010 LV-MaxSonar-EZ21 Ultrasonic Rangefinder sonar sensors, which can from 6-inches to 254-inches, with 1-inch resolution. Any object from 0-inches to 6-inches is typically ranged as 6-inches. They are used in PW mode for outputting. For efficient working of sensors without any crosstalk, we have configured 3 sensors in the chaining mode called AN output commanded loop. This mode of configuration uses 5 pins of each sensors such as VCC = +5V,GND,TX,RX and PWM. While triggering,the first sensor RX pin is held high for a time period > 20micro seconds and < than 48ms.This will start the sensor chain. The first sensor will range, then trigger the second sensor to range and so on for all the sensor in the array.

Mounting of the sensors are made on a curved platform such that the sensors are aimed with a positive slope and not horizontally. This decision is made in order to avoid interference with the ground due to the wide range of detection by the sensors.

MB1010 LV-MaxSonar-EZ21 Ultrasonic sensor

Sensor timing diagram

Sensor's mounting platform Motors DC Motors The DC motors used in the project are 100 RPM low-cost single shaft straight geared motors. They are suitable for lightweight robots that do not require high power or torque. The DC motors are connected to the wheels which are in contact with the base of the ball. The DC motors are driven by a driver module which controls the motor direction and speed. Driver module Control inputs of driver module Servo Motors Write about the servo motor used and its uses. Bluetooth Module Bluetooth module HC-05 is used to communicate between the spherical robot and mobile application. It is implemented to establish the connection between the two so that we can remotely control the robot (to send start and stop signals) and receive the data from the robot directly on the Android application. The data being sent by the robot is current GPS location, ultrasonic range sensor values, and temperature sensor values. Bluetooth module HC-05 HC-05 Pin connections Hardware Interface We have four major hardware modules interfaced with a single SJOne board using different communication protocols. For simplicity sake, we have given a description of how each module is individually interfaced with the SJOne board. In reality, all these modules are connected to a single SJOne microcontroller. Ultrasonic Range Finders The ultrasonic range finders have been interfaced with the SJOne board using PWM. How is it triggered?? Ultrasonic range finders interfacing with SJOne board via PWM Motors The DC motor is connected with the SJOne board via the motor driver module using GPIO. The GPIO signals from SJOne board provide inputs to the motor driver module, which in turn drives the DC motors in forward or reverse direction or stop signal. Servo motor is interfaced with the SJOne board using PWM. DC Motors and driver module connected to SJOne board using GPIO Servo motors interface with SJOne board via PWM The hardware interface of how the DC motors are connected to the wheels which are driven from the SJOne board and how the servo motor is connected with the pendulum to steer the robot in right or left direction can be viewed in the figure below. Internal Hardware connection (Motors) GPS Module GPS module communicates with SJOne board via UART communication. GPS interface with SJOne board via UART communication Bluetooth module The Bluetooth HC-05 module is connected with the SJOne board via UART communication. Bluetooth connection with SJOne via UART Software Design PCB Design SD Card Writing Android Application Software Design Sensors logic DC and servo motor logic Implementation GPS Module Hardware Design Venus GPS Module Antenna for the GPS Module The GPS module used in our project is Venus GPS logger (Venus638FLPx) by Spark fun Electronics. This module is the successor of Venus634LPx and it has a higher update rate and can be configured to operate at an update rate of 20Hz.It can be connected to the PC using a serial to USB converter and configured with the help of a GPS viewer software by SkyTraq which has a GUI and is easy to use.This is handled by the software by sending appropriate commands to the GPS logger when any option is selected by the user. GUI of the SkyTraq GPS Viewer By opening the correct COM port after connecting the GPS module to the PC, serial communication between the GPS module and PC can be established. The GPS logger works at a default baud rate of 9600bps but it can be configured to work at a baud rate of up to 115200bps. The changes in the configuration of the GPS module can be made permanent by writing the commands to the flash instead of the SRAM. The "Cold Start", "Warm Start" and "Hot Start" buttons on the bottom left corner of the screen define how fast a fix can be achieved by the GPS logger. Hot Start: When a 3V battery is connected to the GPS module, it helps the GPS logger in saving information about the previous fix in its memory. This ensures that a fix is attained quickly when the system is switched on the next time. A warm start will happen if the module is switched on again before a specified amount of time, typically two hours. Warm Start: As mentioned above if the module is switched on after about more than two hours then it will take a while for the module to attain a fix. It will take more time to attain a fix compared to the warm start, but is less than the time taken to attain a fix when the module is not fixed with a battery at all. Cold Start: When a battery is not connected to the module at all then there is no information available about the previous fix and it would take a long time to attain a fix. The output of the GPS module can be in NMEA format or SkyTraq Binary Message format. For sending the data from the GPS module to a controller it has to be configured to send data in the NMEA format. There are many message types in the NMEA format but for our project, the GGA type of NMEA output has been used which contains the time, position and fix related data for the GPS receiver. The GGA message will have the following format $GPGGA,hhmmss.sss,ddmm.mmmm,a,dddmm.m m m m,a,x,xx,x.x,x.x,M,,,,xxxx*hh<CR><LF> 1 2 3 4 5 6 7 8 9 10 11 1 UTC of position in hhmmss.sss format 2 Latitude in ddmm.mmmm 3 Latitude hemisphere indicator, ‘N’ = North, ‘S’ = South 4 Longitude in dddmm.mmmm 5 Longitude hemisphere indicator, 'E' = East, 'W' = West 6 GPS quality indicator 0: position fix unavailable 1: valid position fix, SPS mode 2: valid position fix, differential GPS mode 3: GPS PPS Mode, fix valid 4: Real Time Kinematic. System used in RTK mode with fixed integers 5: Float RTK. Satellite system used in RTK mode. Floating integers 6: Estimated (dead reckoning) Mode 7: Manual Input Mode 8: Simulator Mode 7 Number of satellites in use 8 Horizontal dilution of precision 9 mean sea level 10 Differential reference station ID 11 Checksum Hardware Interface GPS module is interfaced with the microcontroller via UART. GPS Interfacing with SJOne board via UART Software Design Software Flow for the GPS Implementation SDCard Hardware Design Hardware Interface Software Design Implementation Bluetooth module and Android Application Hardware Design Hardware Interface Software Design Implementation PCB Designing Hardware Design PCB board PCB Schematic PCB board PCB board } Hardware Interface Software Design Implementation Testing & Technical Challenges Describe the challenges of your project. What advise would you give yourself or someone else if your project can be started from scratch again? Make a smooth transition to testing section and described what it took to test your project. Include sub-sections that list out a problem and solution, such as: My Issue #1 Discuss the issue and resolution. Conclusion Conclude your project here. You can recap your testing and problems. You should address the "so what" part here to indicate what you ultimately learnt from this project. How has this project increased your knowledge? Project Video Upload a video of your project and post the link here. Project Source Code Sourceforge Source Code Link References Acknowledgement Any acknowledgement that you may wish to provide can be included here. References Used List any references used in project. Appendix You can list the references you used.