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University of Colorado Time Systems

University of Colorado Time Systems. Lucas Buccafusca Sean DesMarteau Tanner Hannam Jeff Lassen Joshua Yang. Contents. Project Overview Functional Description of Parts and Interfaces Specifications Network Structure Description of Software Preliminary Parts List Division of Labor

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University of Colorado Time Systems

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  1. University of Colorado Time Systems Lucas Buccafusca Sean DesMarteau Tanner Hannam Jeff Lassen Joshua Yang

  2. Contents Project Overview Functional Description of Parts and Interfaces Specifications Network Structure Description of Software Preliminary Parts List Division of Labor Schedule Questions

  3. CURRENT TIMING LAYOUT 8 Inputs Per Lane 3 Pushbuttons, 2 Touchpads, 1 Relay Judging Platform, 2 Start Inputs (Speaker/LEDs on Start Block)

  4. CURRENT TIMING LAYOUT • 2 Outputs Per Lane • Start Information: • Speaker Tone • Flashing Light on RJP • Strobe Light on Start System

  5. STANDARD 8 LANE SETUP

  6. DOWNSIDES TO CURRENT SYSTEM • While current system is satisfactory it provides downsides. • TOO MANY WIRES!!!! • Very elaborate setup • Wires/touchpads can be easily ruined by water/human handling if not cared for properly • Therefore an upgraded system is desired to combat these downsides

  7. Project Scope Evolve from • Wired Connections • Precise timing relations through copper connections • Need for conduits and elaborate setup • To wireless input and output nodes • Mesh network synchronized to 1 msec • Easy setup

  8. Objectives Create system of 80+ wireless nodes to account for all inputs/outputs per lane for 10 lane pool Test for accuracy and reliability of system under normal race/pool conditions

  9. Level 0 for 1 Lane Power, Battery Timing System Scoreboard Push Buttons Speakers Touchpad Start System Light Relay Judging Platform (RJP)

  10. Level 1 For 1 Lane Power, Battery Data Signal Power Power Signal Master Timer Push Buttons Computer/ Scoreboard Voltage Regulator, 3.3V Device Input Signal Touchpad Speakers Wireless Mesh Network Relay Judging Platform (RJP) Start System Signal Light Start System Signal Start System

  11. Level 2 for 1 Lane Power, Battery Data Signal Voltage Regulator, 3.3V Root Node Power Push Buttons Xbee(Master Timer) Xbee Scoreboard Xbee Touchpad Xbee Xbee Speakers Relay Judging Platform (RJP) Xbee Start Mic Xbee Xbee Light Start System Start Button Xbee Xbee

  12. Level 3 for 1 Lane Power, Battery Data Signal Voltage Regulator, 3.3V Root Node Power Timer Start Signal Push Buttons Xbee(Master Timer) Scoreboard Xbee Touchpad Xbee Xbee Speakers Xbee Relay Judging Platform (RJP) A/D Convertor Mic Xbee Xbee Light Start System Start Button Xbee Xbee

  13. BTR Node

  14. TIMER Node

  15. START Node

  16. SPEAKER Node

  17. SCOREBOARD Node

  18. Network Structure • Network orientation will be a Wireless Mesh Network (WMN) • Properties of a WMN include: • Ability to Self-form/Self-heal (meaning that as we add nodes to the network, we are able to wirelessly seam them together without trouble) • Relatively stable topology • Data can reach the final destination in a relatively fast amount of time

  19. Network Setup • Will be functioning at 2.4GHz • Allows for easy testing of latency and robustness

  20. Network Setup • Initial Wireless Synchronization will be implemented with Timing-sync Protocol for Sensor Networks (TPSN) • Offers distinct advantages to other wireless systems • Average Error due to propagation is relatively constant as more nodes are added • Requires fewer messages sent, and is more energy efficient.

  21. TPSN Setup • Consists of two stages: Network Discovery and Synchronization

  22. Discovery Phase: • The level discovery phase is run on network deployment. First, the root node is assigned. Once the root node is determined, it will initiate the level discovery. • The neighbors of the root node will then assign themselves as level 1. They will in turn send out the level_discovery packet to their neighboring nodes. This sequential labeling of nodes continues until all nodes are given a level • After the discovery phase, there is a moment where any nodes that are expected to be in the network that may have failed communication can reconnect

  23. Synchronization Phase • The basic concept of the synchronization phase is two-way communications between two nodes. Similar to the level discovery phase, the synchronization phase begins at the root node and propagates through the network.

  24. Synchronization Phase • T1, T2, T3, and T4 are all measured times. Node A will send a packet at T1 to Node B. This packet will contain Node A's level and the time when it was sent. Node B will receive the packet at T2. T3 is when Node B sends the acknowledgment to Node A. That packet will contain the level number of Node B as well as T1, T2, and T3. By knowing the drift, Node A can correct its clock and successfully synchronize to Node B.

  25. Period of TPSN • Desired Worst Case Accuracy = (Worst Case Sync Error) + (Worst Case Clock Drift * Period of TPSN) • Worst Case Accuracy=1ms • Worst Case Sync Error= 75μs • Worst Case Clock Drift= 4.75 μs/s • So our Period is ~3 minutes

  26. Reason for TPSN Selection • TPSN offers certain advantages over the other common wireless synchronization system (RBS) • More energy efficient (fewer messages sent) • Error is (mostly) independent to the number of nodes and typically 2x better than RBS

  27. Node Types Button Nodes Timer Node Start System Node Speaker Node Scoreboard Node

  28. Primary Inputs • Hardware Inputs • Rising or falling edge voltage 0-3.3V (BTR nodes) • Analog input from microphone at 8kHz into 16 bits (starter) • Radio Inputs • Event packets from Xbee Radio • Time sync packets from Xbee radio

  29. Key Input Methods • Event Interrupt Interface • Collects timestamp and event type • Timing event handler • Uses collected information and adds origin node info • Digital signal handler • Takes digital signal and formats for output to radio • Xbee packet interface • Interface to collect packets from radio • Xbee packet handler • Interprets packet from interface

  30. Information Packets • Packets to contain key information based on packet type • Event packets • Timestamp, event type (relay pad, touchpad etc.), origin node information • Start packets • Digital voice signal, start signal • Time sync packets

  31. Primary Outputs • Hardware Outputs • Analog signal from speaker node to speaker • DC signal to strobe light • Radio Outputs • Packaged information to radio • Time sync information • Packaged information to Computer (from timer node)

  32. Key Output Methods • Digital signal to speaker interface • Takes digital packets and outputs to speaker • Strobe light interface • Sends voltage to strobe • Xbee/UART interface • Sends information to radio or computer via UART communication

  33. Xbee Output Signal Custom firmware settings flashed to radios Enables different settings for packet length, baud rate etc. Enables different network setups and node identification

  34. Example Xbee output

  35. MC9S08GB60A – MCU • Suited for low power applications • Has required elements • Two SCI Lines • 16-bit Timers • Necessary number of I/O • External IRQ Pin • 10 bit ADC • Well documented through App. Notes

  36. MC9S08GB60A – Progress • Working with Development board • M68DEMO908GB60E • Working Functions: • 1 kHz timer interrupt (for 1 ms precision) • External IRQ pin for button interrupts • Serial interface to Tera Term on Computer

  37. MC9S08GB60A – Next Step 1 • Programming for power efficiency • Also a WAIT mode

  38. MC9S08GB60A – Next Step 2 • Communication of MCU to MCU through Xbee Mesh Network • Synching of two 16 bit variables • Send times of when Interrupts occur between Nodes • Testing Routines • Start with 1 Lane – Race Simulation

  39. Testing – Race Simulation • Purpose – Test how well nodes are synced relative to Master Timer Node • Steps: • 1. Synch time across all nodes • 2. Run simulation (Start On) • 3. Compare expected times to times received

  40. Roles and Responsibilities Power Specifications – Josh Design for efficiency on per node basis Network Setup – Lucas Implementation of Mesh Network/Timing Sync Software – Jeff Coding Xbee Hardware Design – Sean Functional and test circuitry needed for each node Testing Manager – Tanner Microcontroller programming

  41. Schedule Plan is to continue to follow the schedule designed by Tom Brown for the year-long Capstone course In addition, try to meet deadlines set by Colorado Time Systems

  42. Schedule Critical Design Review-12/11/12: Presentation Milestone 3- Critical Path Prototype Unit Tests -2/12/12: Test plan presented to TAs and instructors Milestone 3 (continued)- Test Results and Analysis -2/19/12 Milestone 4- I&T Sub-system and System Integrated Testing Refinement-3/12/12 Capstone Design Expo – 4/23/2012: Completed prototype with all necessary materials and documentation presented to instructors, TAs, colligates, and general public.

  43. Questions?

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