Milestone #4 The Wedge o’ Death

Presentation Overview New Hardware New Code Milestone Results Time Log Questions 2

Moe’s New Bumper Old Plastic Bumper - from RC Mustang - fixed in place - good for ramming 3 New Balsa Bumper - two-switch bump sensor - floating - delicate touch

Moe’s New Sensors Upright sensor arrays utilize phototransistors only No emitters Three phototransistors on front for light detection 4

Moe’s New Switches Two mercury switches (ascending/descending) Wired so that either can send signal - State detection vs. state change Neither active when Moe is level Software used to filter noise due to motion 5

Disaster Strikes 6 Damage sustained to line following sensors during testing Balsa wood is fragile Reinforced sensor array via lamination Wood screws to prevent damage until rescue arrives

Moe’s New Code FILTERING - 3 arrays - line state - light state - tilt state - 5 consecutive readings from line-following sensors - 5 consecutive readings from light sensors while in Light Channel - 5 consecutive readings from mercury switches for level detection -sampled over longer time interval -nested FOR loop On-the-Fly Buzzing - increased performance in Light Channel and Wedge of Death Old line-following code worked perfectly for Wedge of Death 7

Moe’s New Code Handling the fork - traversing fork difficult - code from last milestone would pick correct path ~50% Solutions 1) going blind - programmed motion unreliable 2) triggering on two sensors - unreliable due to line-following code 3) triggering of outside right sensor - 5 soft right turns to get us back to the Wedge of Death line - source of drama 7

Moe’s Motion Logic Outside Left 9 Inside Left Outside Right Inside Right

Milestone Strategy 10 - Room of Doom - Light Channel (iffy) - Wedge of Death (solid) - Piccadilly then return to the line - repeat…

Milestone Results 11 Part 1 - Room of Doom, Light Channel, Wedge of Death - perfect first time, just as we expected - even completed both Piccadillys Part 2 - Room of Doom, … - things went wrong in the Light Channel - trouble changing states results in Moe losing track of where he is - infinite line-following state - scored 200 points for completing Room of Doom once Placed 5th overall…

Planned Improvements 12 Fix auto-start problem (vital) Fix Light Channel Code Add light to buzzer circuit to better signal state changes Incorporate bump detection Perhaps fix Pinbot code Create a safe place to lift Moe

Milestone Time Log 13 Hardware: 11 hours Software: 24 hours Documentation: 20 hours Total: ~55 man hours

Questions ? 14