Holland_Devin_J 725KB Apr 22 2014 05:28:30 AM
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1. drums that are spun up to their maximum speed A foam dart is fed in between the two drums using a mini servo The turret relies on gravity to reload the turret after the mini servo returns to the docked position Lastly the sweeping IR sensors are allowed to pivot only when a Hitec servo pulls a string inside the chassis which rotates a large wooden disk Both the IR sensor and the wooden disk are fixed to a 1 5 4 40 screw When returning to the front the disks use a set of springs to pick up the slack in the line Sensors MinuteMachine s two important senses are infrared distance measuring and an onboard vision system To visually scan its surroundings the robot will use the onboard camera built into the Android Then by using OpenCV to detect color blobs it will send filtered data to the microcontroller to decide what to do A custom app was needed to collect and process the information from the Android and communicate with the microcontroller The robot will also use IR light to detect the world around it and if they were to fail bump switches would let the robot know it encountered something solid Special Sensor The special sensor used on MinuteMachine is a camera which is incorporated in an Android device The live feed will be analyzed frame after frame by a software library known as OpenCV This OpenCV library can be used on many different platforms including Android To use It have written an app in Eclipse and could possibly distri2. D display and system buttons On top of the main platform resides a pan amp tilt rig containing a Samsung S4 Android device and dart launching device When MinuteMachine is first turned on the voltage from the 12v lipo battery is split between a motor controller and a 5v regulator that powers the microcontroller and 10 additional devices The LCD will immediately prompt the user to select a mode from a list after a short bootup sequence The modes include a Full Mode to launch the main program a Turrent Mode to isolate the targeting system and a Calibration Mode to set two custom threshold values for obstacle avoidance In Full Mode the MinuteMachine will use the microcontroller to navigate an area this mode relies on an interrupt that automatically receives coordinates from the android device When a set of coordinates dependant on the center of mass for both colors passes a series of filters built into the Android itself passes the data is passed using USART over the audio jack to the microcontroller When a positive match has been detected MinuteMachine will stop and look at the specified coordinates and initiate Target Mode If within the next five seconds another set of coordinates are captured and within the tolerances for the center of the screen a firing sequence begins The launcher motor will power up and a single dart will be fed into it MinuteMachine will continue to fire at the target until it disappears and will resume n
3. MinuteMachine Devin Holland April 21 2014 University of Florida Department of Electrical and Computer Engineering EEL4665C IMDL Spring 2014 Instructors A Antonio Arroyo Eric M Schwartz TAs Joshua Weaver Andy Gray Nicholas Cox Daniel Frank Table of Contents ADS AAA AAA da 3 Executive SUMMAN is A A toe E ct eee 3 INTO UC AA A eet eva ca 5 Integrated Mii A a AAA ara 6 Mobile Plato A AAA teen aan 7 ACTUATION Ss mica dida did ees 7 A Hoh Rei aa Eea AE E E eet eile teee een Es 8 ime A en ee ree 8 BehaviOrss icc cikeiheh Aine thane di ea lee eee 9 Audio to Serial PCB ResultS oooooonnnnccconccccnonnnonnoccnnonnnonnncnnono corno nn nnnna nc ronnnnnnnn cnica ness 10 CONnCIUSION ssi BiH eet hier a a a ee ee eae 12 Documentation haa chad Bena Gh Behe ee Ae ee i 12 Appendices nics cc25s data 12 Abstract Robotics exist to improve humanity by taking over the repetitive uncomfortable and dangerous aspects of our lives One of the most confrontationally dangerous situations to be in is where the danger comes from humans themselves am modeling my robot with the duties of an urban police officer or soldier want my robot to be able to provide a protected environment by emulating the duties of law enforcement By watching out for situations in progress it will be able to interfere and prevent any unnecessary harm to the victim When the MinuteMachine identifies unregistered weaponry in the form of a concentric color patter
4. amsung S4 User Manual http cache vzw com multimedia mim sam_galaxy_s4 samsung_galaxy_s 4 um pdf e OpenCV Resource http opencv org e Sharp IR Rangefinders http www sharpsma com webfm_send 1489 Appendices MinuteMachine is open source and everything can be found at https sites google com site MinuteMachinelMDL
5. avigating the area Introduction The goal for this robot is to detect a disturbance and neutralize the situation To detect a disturbance the robot will scan for a certain color pattern to attempt to find unregistered weaponry and shoot at it Afterwards the robot will resume patrolling I ve always wanted to build robotics that would integrate into our everyday lives and help us in some way For this project wanted to do something ambitious wanted to learn how to use a sensor that has previously been out of my reach wanted a vision system Also wanted to recycle old smart phones and use them to their full potential After learning about a vision library called OpenCV that could be installed on my android was set Learned how to write Android apps and how to incorporate OpenCV into it This report will cover the construction and go over some details of the MinuteMachine The machine will operate in one of two user selected modes Full Mode and Turret Mode In Turret Mode the MinuteMachine will remain stationary and scan for any unregistered weaponry In Full Mode the MinuteMachine will navigate an area and flip to Turret Mode if a target is spotted Integrated System The final architecture of MinuteMachine can be seen in Figure 2 The secondary systems are controlled by an ATxmega128A1U microprocessor The ATxmega will be connected through USART over the audio jack to an onboard Android mobile that will handle the visual proce
6. bute it throughout the world in the app store The inspiration to use an onboard camera came from the desire to learn how to use one Having the skill to work with discarded old smart phones opens a plethora of avenues that could go down that couldn t before The learning curve however is very steep and I have spent most of my time slugging through debugging errors However successfully managed to learn everything needed to see and transmit the sensor data My app can calculate the X amp Y coordinates of the center weight of two separate colors When the app first boots it scans it s environment for a predetermined set of colors an example of this can be seen in Figure 2 To reduce the number of false positives the colors will need to follow a pattern sharing the same center weight as seen in Figure 2 Bottom Once the colors have been detected the coordinates are sent via USART over the audio jack The coordinates will be centered on by the pan tilt system and shot at by an onboard Nerf gun Figure 2 Left Before OpenCV Right After OpenCV Bottom Matching center weights signified by circles To gather sensor data the Android mobile will be brought to different lighting conditions across campus to see if it can still detect the predicted colors Both indoor lighting of the New Engineering building the IMDL lab and my home followed by general outdoor lighting will be tested Behaviors MinuteMachine s default behavio
7. n it will lock on to the offending weaponry and fire Executive Summary MinuteMachine is an autonomous robot created to navigate a typical hallway that you might find in an office environment The main objective while navigating an area is to autonomously identify concentric colored targets and shoot them One of the goals for this project was to build a platform that is completely self contained requiring no external signals for any system This was achieved by integrating an off the shelf Android device to handle the vision system Locomotion is provided by a unique drive system A single motor in the rear of the robot provides all the power This single motor is attached to a single wheel that can pivot 180 to enable turning in place In addition a pitman arm is used to drive another steering mechanism in the front MinuteMachine was designed this way to gain the ability to strafe at an angle towards a target Figure 1 MinuteMachine s dual steering capabilities Two bump sensors and two IR sensors were placed on the front for obstacle avoidance Concealed inside the MinuteMachine can pivot the two IR sensors synchronously to maximize the sphere of detection for any obstacles or walls Inside and out of view resides everything required to get the MinuteMachine powered and running Included is the 12v lipo battery motor controller 5v regulator and my power and signal distribution PCB my audio to serial PCB microcontroller 3 servos LC
8. r is to avoid obstacles while patrolling In this default behavior it will observe it s surroundings If at any time it detects a solid color which will represent a weapon it will switch into a second mode that will target the object and fire a dart Audio to serial PCB amp Results One of the most difficult things that encountered with the android was how to send over the data to the microcontroller At first a Bluetooth module was going to be used but due to cascading errors and an approaching deadline it was tossed for a more reliable method Utilizing various online sources was able to get a program working that would send strings of data over the audio jack using USART protocols However the signal straight from the Android was weak and negative as seen in Figure 3a Tek Run SOkS s Sample MM 4 Android Figure 3a Serial data from Android Using the circuit schematic as seen in Figure 4 was able to greatly amplify the data signal eee ee 5 22 BS gt SERIAL However the signal was active high as seen in Figure 3b So an inverter was added to the output to make the data signal compatible with the microcontroller as seen in Figure 3c With a working circuit soldered it together and gave it one final test as seen in Figure 5 Ch High 3 92 Chi tow ay Android 3 04v Android 3 04v Comparator 3 92v H Comparator 3 92v H Inverter 4 80v L Figure 3b Left 3c Right Serial data ci
9. rcuit output Figure 5 Below Finalized circuit Conclusion have learned a lot from building MinuteMachine designed it so could always come back and repurpose it Taking advantage of the T Tek to design all the parts needed in a computer was a fantastic tool that never had access to The ability to design anything could come up with was invaluable Later on in the semester tried to make some simple parts by hand and even my best work was shadowed by a the same time spent on a computer With all the experience got from working at the IMDL my next design will be more maintenance friendly with less snaking wires because now know how to plan ahead Before the IMDL had never worked with Androids or OpenCV In order for me to finish my robot had to learn how to program in both of their native languages Java and C This was a major accomplishment for me when got everything to cooperate a few weeks before the end of the semester feel as if have only scratched the surface of what can do with OpenCV and will continue to upgrade the software of MinuteMachine Documentation e ATxmega128A1U datasheet http www atmel com Images Atmel 8331 8 and 16 bit AVR Microcontroller XMEGA AU_Manual pdf e Android Serial over Audio resource http robots everywhere com re_wiki index php title Serial_on_Android_using_the_audio_ port e ANT 100 Motor controller http www robotmarketplace com products LB ANT100 2 html e S
10. ssing The ATxmega controls all functions with the Android acting like a sensor which only provides data The block diagram in Figure 2 below shows all the components and ties between them 12v Lipo Drive Motor Motor Controller Launch Motor ATxmega128A1U 5v Regulator Power Distribution PCB 4 momentary Audio to 6 IR LCD push buttons Serial PCB Servos Sensors Android Figure 2 MinuteMachine system block diagram Mobile Platform The vehicle of MinuteMachine is a unique reverse powered tricycle This design was chosen over others because it ll give all the benefits of a steering and tank tread design combined it will provide a variety of driving capabilities One main benefit of this design is the ability to strafe towards a target Designed to drive over indoor surfaces and among multiple objects the drive system is housed and protected inside the frame which provided a low profile to roll over tile and smooth carpeting Actuation MinuteMachine uses a HG16 Copal motor and one Hitec HS 422 servo to power and steer the rear drive system respectively the single rear wheel will be able to rotate 180 to provide pivoting and minor course corrections Another Hitec servo controls the front steering which provides major course corrections and interesting maneuvers The firing mechanism will be mounted on a pan amp tilt system powered by another 2 Hitec servos The brushed motors use two counter spinning
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