DuckhunterFinal Project Presentation

Taylor Barton and Andrew Lisy

tbarton@mit.edu, alisy@mit.edu

6.111 - Digital Electronics Laboratory

Massachusetts Insitute of Technology

Duckhunter – p.

Outline of Talk

Objectives and System Overview

Block Diagram

Input System

Output Servomechanizm

Calibration

What’s Next?

Conclusions

Taylor Barton

Andrew Lisy

Duckhunter – p.

Objectives and System Overview

Objective: build a servomechanism that plays Nintendo’sDuck Hunt in skeet mode

Nintendo

switchbox

TV light gun

servos

optical sensorcalibrate

Duckhunter

Duckhunter – p.

Block Diagram

calibration video

timing module

light calibratorwhite v_sync

h_sync

xvga

hcount

vcount

65 MHzclock

c_videoto TV

comparator hit

thresh

light gunphototransistor

c_ready

x_hit

y_hit

FSM

c_enc_x_coords

c_y_coords

conversion

x_coord

y_coord

x_offset

y_offset

8

(LED[0])

debounce

7

theta_coord

phi_coord8

8

drivermotor

distance to TV(switch[6:0])

to motors

debouncecalibrate(switch[7])

black

Each block also gets clock and reset inputs

calibrated

calibrator

FSMstate: oneof fivecoord pairs

8 8

<δ?

<δ?

counts v and hsyncs betweenwhite and hit

coordinate

use trig toconvert totheta and phi based onTV distance

tv_dist

8

8

8

8

8

A/D controller

AD7125

on high c_en andc_ready, blanksscreen and pulses black, then colors screen white andpulses white

two registers:

black and whitescreen.

sensor vals for

light_val

x1_coord_pred

y1_coord_pred

x2_coord_pred

y2_coord_pred

8

8

8

8

ADC0820

shoot to triggerof light gun

8

Andrew Lisy

Taylor Barton

timer

start_counttime

disk spacing delayinput vectorsystem time

physics1

disk spacing delayinput vectorsystem time

physics2

wait FSM

start_d1

start_d2

enable

enable

0

video

19

vsync

<x,y>

phy1_en

phy2_en

10

t2timersave

time offset 8

8

8

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Input System

Function: Translate the video output of the Nintendo totime-adjusted coordinates for the gun.

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Input System

Function: Translate the video output of the Nintendo totime-adjusted coordinates for the gun.

Subcomponents:

Duckhunter – p.

Input System

Function: Translate the video output of the Nintendo totime-adjusted coordinates for the gun.

Subcomponents:

Vector Analyzer - from frame sequence, detect discs anddetermine initial velocity vector < −→x1,

−→y1 > for each disc.

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Input System

Function: Translate the video output of the Nintendo totime-adjusted coordinates for the gun.

Subcomponents:

Vector Analyzer - from frame sequence, detect discs anddetermine initial velocity vector < −→x1,

−→y1 > for each disc.

Physics Engine - Using vectors, apply formulas:

xt = −→x0t, yt = −→y0t + 1

2gnest

2

where gnes = experimentally determined gravity force ofNES (in pixels/frame2).

Duckhunter – p.

Input System

Function: Translate the video output of the Nintendo totime-adjusted coordinates for the gun.

Subcomponents:

Vector Analyzer - from frame sequence, detect discs anddetermine initial velocity vector < −→x1,

−→y1 > for each disc.

Physics Engine - Using vectors, apply formulas:

xt = −→x0t, yt = −→y0t + 1

2gnest

2

where gnes = experimentally determined gravity force ofNES (in pixels/frame2).

Timer - keeps track of delays in 1/10 seconds.Duckhunter – p.

Input System: Vector Analyzer

1. Wait for white ’blip’ to appear just above scoring panel.

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Input System: Vector Analyzer

1. Wait for white ’blip’ to appear just above scoring panel.

2. When blip is found, record coordinates in register bankA1. Wait a frame, record new coordinates to to A2 andassert start_d1.

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Input System: Vector Analyzer

1. Wait for white ’blip’ to appear just above scoring panel.

2. When blip is found, record coordinates in register bankA1. Wait a frame, record new coordinates to to A2 andassert start_d1.

3. Set ’disc_present’ register to high to indicate we havecoordinates for one disc.

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Input System: Vector Analyzer

1. Wait for white ’blip’ to appear just above scoring panel.

2. When blip is found, record coordinates in register bankA1. Wait a frame, record new coordinates to to A2 andassert start_d1.

3. Set ’disc_present’ register to high to indicate we havecoordinates for one disc.

4. Output < xA2 − xA1, yA2 − yA1 > to vector output

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Input System: Vector Analyzer

1. Wait for white ’blip’ to appear just above scoring panel.

2. When blip is found, record coordinates in register bankA1. Wait a frame, record new coordinates to to A2 andassert start_d1.

3. Set ’disc_present’ register to high to indicate we havecoordinates for one disc.

4. Output < xA2 − xA1, yA2 − yA1 > to vector output

5. Repeat process for next disk (using register bank B1,B2). When blip for next disk is found, assert start_d2.

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Input System: Physics Engine

Inputs: Vector from Vector Analyzer, system time t, gunaiming latency taim, shot spacing offset tsp

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Input System: Physics Engine

Inputs: Vector from Vector Analyzer, system time t, gunaiming latency taim, shot spacing offset tsp

Output: Coordinates of the two discs, compensating foraiming latency and spacing offset, as a function of t, taim, tsp

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Input System: Physics Engine

Inputs: Vector from Vector Analyzer, system time t, gunaiming latency taim, shot spacing offset tsp

Output: Coordinates of the two discs, compensating foraiming latency and spacing offset, as a function of t, taim, tsp

Implementation: The first physics engine receives input t

from timer, taim from experimental values, and tsp wired toground (since it handles the first disc, there is no spacingdelay). The second module receives t and taim from thetimer and experimental values, as well as tsp from the t2module.

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Servomechanism

The output system takes the (x, y) coordinate from the physics

engine and translates it into angles for the servomechanism.

distance

height

(0,0)

inputs: (x, y) coordinates, (x, y) offsets, distance from TV, height

(constant)

outputs: motor control signal

Servo resolution ≈ 1 degree.

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Servomechanism: Calibration

hcount

vcou

nt

(0,0)

Calibrator outputsvideo to TV: first black,then white screen.

Timing module countsthe hsync and vsyncsignals between thestart of the whitescreen and the gunsensing a hit to deter-mine position.

System is calibrated by comparing intended and actualcoordinates.

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What’s next?

1. Real-time Feedback: If we are able to find a version ofthe NES Duck Hunt game that uses a specific mode ofhit detection (blanking then whiteing the entire screen),we can implement real-time calibration to our system,thus increasing the accuracy.

Duckhunter – p. 10

What’s next?

1. Real-time Feedback: If we are able to find a version ofthe NES Duck Hunt game that uses a specific mode ofhit detection (blanking then whiteing the entire screen),we can implement real-time calibration to our system,thus increasing the accuracy.

2. Miss Correction: If possible, we will implement a hitdetection mechanism which sends a signal into the FSMafter the gun is fired. If the signal is low, re-aim and fire.If high, move to the next state.

Duckhunter – p. 10

What’s next?

1. Real-time Feedback: If we are able to find a version ofthe NES Duck Hunt game that uses a specific mode ofhit detection (blanking then whiteing the entire screen),we can implement real-time calibration to our system,thus increasing the accuracy.

2. Miss Correction: If possible, we will implement a hitdetection mechanism which sends a signal into the FSMafter the gun is fired. If the signal is low, re-aim and fire.If high, move to the next state.

3. Duck Hunt Mode: Depending on the mechanicallimitations of our tracking and firing mechanism,Duckhunter could be implemented to play the DuckMode of Duck Hunt

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Conclusion

Mechanical considerations limit how fast and accuratethe digital system can be.

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Conclusion

Mechanical considerations limit how fast and accuratethe digital system can be.

The calibration routine, while seemingly mundane, is avery critical part of the system, since the gun will bemoved from station to station. Manual calibration wouldbe tedious and unreliable.

Duckhunter – p. 11

Conclusion

Mechanical considerations limit how fast and accuratethe digital system can be.

The calibration routine, while seemingly mundane, is avery critical part of the system, since the gun will bemoved from station to station. Manual calibration wouldbe tedious and unreliable.

Determining the coefficients for the physics engine mayrequire a separate system to track and analyze datafrom previous runs.

Duckhunter – p. 11

Conclusion

Mechanical considerations limit how fast and accuratethe digital system can be.

The calibration routine, while seemingly mundane, is avery critical part of the system, since the gun will bemoved from station to station. Manual calibration wouldbe tedious and unreliable.

Determining the coefficients for the physics engine mayrequire a separate system to track and analyze datafrom previous runs.

If we are successful, this system may succeed where wehave failed: reaching the final level of Duck Hunt

Duckhunter – p. 11