Milestone #4The 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 toline 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%

Solutions1) 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

- 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