Difference between revisions of "Baseball"
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==Overview== |
==Overview== |
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The goal of this project was to make an interactive baseball game inspired by pinball |
The goal of this project was to make an interactive baseball game inspired by pinball. There is a solenoid-powered bat and a pitching mechanism that utilizes a motor and lever arm setup. Both of these are controlled by buttons so that two people can play against each other. The game has targets for a single, double, triple, and home run, with a simple photodiode-phototransistor circuit to sense the ball. There are LEDs to light up each base as well as a scoreboard containing two seven-segment displays and LEDs for outs. |
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This page will describe the mechanical design, electrical design, and code for the project. |
This page will describe the mechanical design, electrical design, and code for the project. |
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===Play Field and Housing=== |
===Play Field and Housing=== |
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<table border="1" width="35%"> |
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<tr> |
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<td width="17.5%"> |
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<p><font size="-1"><b>Part</b></font></p> |
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</td> |
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<td width="17.5%"> |
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<p><font size="-1"><b>Quantity</b></font></p> |
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</td> |
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</tr> |
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<tr> |
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<td width="17.5%"> |
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<p><font size="-1">Plywood</font></p> |
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</td> |
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<td width="17.5%"> |
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<p><font size="-1">~8ft<sup>2</sup></font></p> |
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</td> |
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</tr><tr> |
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<td width="17.5%"> |
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<p><font size="-1">Wood Screws</font></p> |
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</td> |
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<td width="17.5%"> |
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<p><font size="-1">21</font></p> |
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</td> |
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</tr><tr> |
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<td width="17.5%"> |
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<p><font size="-1">Set Screws</font></p> |
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</td> |
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<td width="17.5%"> |
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<p><font size="-1">10</font></p> |
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</td> |
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</tr><tr> |
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<td width="17.5%"> |
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<p><font size="-1">Acrylic Board</font></p> |
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</td> |
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<td width="17.5%"> |
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<p><font size="-1">~3ft<sup>2</sup></font></p> |
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</td> |
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</tr> |
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</table><br/> |
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⚫ | |||
The general concept is to have a slanted surface similar to a pinball machine. The ball will roll down and the user will try to hit it back up into a single, double, triple or homerun. These "hits" have dampening backstops and milled down grooves to channel the ball into a hole where a sensor is placed. If none of these are hit then the ball rolls back down towards the bat and into an out hole. This was done to limit the number of holes and sensor we would need to create. There are rails along the play field so the ball will not fly off. Underneath, there is a recess, which is an oppositely slanted board to channel the ball back to the pitching apparatus. The housing has sides to mount the bat button and keep the ball from sliding out of the recess. A acrylic sheet was used to wrap around the back as the rear wall. Holes were cut to allow pitching and scoreboard display. |
The general concept is to have a slanted surface similar to a pinball machine. The ball will roll down and the user will try to hit it back up into a single, double, triple or homerun. These "hits" have dampening backstops and milled down grooves to channel the ball into a hole where a sensor is placed. If none of these are hit then the ball rolls back down towards the bat and into an out hole. This was done to limit the number of holes and sensor we would need to create. There are rails along the play field so the ball will not fly off. Underneath, there is a recess, which is an oppositely slanted board to channel the ball back to the pitching apparatus. The housing has sides to mount the bat button and keep the ball from sliding out of the recess. A acrylic sheet was used to wrap around the back as the rear wall. Holes were cut to allow pitching and scoreboard display. |
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===Bat=== |
===Bat=== |
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The Bat was fashioned out of wood on the band saw and sanded to a finish. Two holes were drilled: one to act as an anchoring pivot point and the other to be attached to an actuator. A |
The Bat was fashioned out of wood on the band saw and sanded to a finish. Two holes were drilled: one to act as an anchoring pivot point and the other to be attached to an actuator. A [http://www.goldmine-elec-products.com/prodinfo.asp?number=G16036 Spring Return Solenoid], run on two 9.6V rechargeable batteries in series, was used to actuate the bat. The user interface was a simple push button usually stocked in the lab. This button was located on the right side of the game similar to where pinball buttons are located. |
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In order to make the game more like baseball we set up a system to only allow the user to swing |
In order to make the game more like baseball we set up a system to only allow the user to swing once per pitched ball. To learn more about this look below to '''Bat Relay'''. |
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===Pitcher=== |
===Pitcher=== |
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To actuate the ball up to a position to be "pitched" a motor and scooping arm were used. The motor was hooked up to a |
To actuate the ball up to a position to be "pitched" a [http://www.trossenrobotics.com/store/p/5145-RS-385-Motor-7-2V.aspx RS385 motor] and scooping arm were used. The motor was hooked up to a 9.6V battery found in the kits. Once activated the arm turns upwards until hitting a static bar. Attached to the bar is a lever switch which sends a pulse to the PIC telling it that a pitch has been thrown. The momentum of the ball would shoot it out of the scoop where a curved ramp would project it onto the play field. The motor is attached to a simple push button so another player can pitch creating a more interactive game. The arm, bar and ramp were made out of scrap sheet metal found in the machine shop. |
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===PIC Schematic=== |
===PIC Schematic=== |
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[[Image:Baseball_PIC_Circuitry.jpg|left|The PIC Circuit|thumb|300px]] |
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⚫ | |||
===Circuit Diagram=== |
===Circuit Diagram=== |
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Sensor |
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[[Image:baseball_sensor_circuitry.jpg|left|Example of Sensor Circuit|thumb|300px]] |
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<br clear=all> |
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Pitcher and Bat |
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[[Image:baseball_pitcher_bat_circuitry.jpg|left|Pitcher and Bat Circuit|thumb|300px]] |
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<br clear=all> |
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LED Circuit |
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[[Image:baseball_LED_circuitry.jpg|left|Example of LED Circuit|thumb|300px]] |
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<br clear=all> |
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Seven Segment Display |
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[[image:CircuitDiag.jpg|thumb|300px|Circuit diagram for the 7-segment display circuit|left]] |
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<br clear=all> |
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===Photodiode/Phototransistor Sensor=== |
===Photodiode/Phototransistor Sensor=== |
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An IR optical sensor was used to detect the ball falling through a hole. |
An IR optical sensor was used to detect the ball falling through a hole. The transistor will be receive a large amount of infrared radiation constantly, until a ball falls through. The obstruction will send a pulse to the PIC and either an out, single, double, triple or homerun will be executed. |
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[[Image: |
[[Image:Baseball_Ball_Sensor.jpg|left|One of the Sensors Used to Detect the Ball|thumb|300px]] |
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<br clear=all> |
<br clear=all> |
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===Bat Relay & Power Supplies=== |
===Bat Relay & Power Supplies=== |
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In order to power our solenoid and motor we needed external power. We used the 9.6V rechargeable batteries found in the lab kits. The first battery is permanently connected to the pitching motor as well as in series with the second battery. The two batteries in series are connected to the solenoid via a relay. When the PIC sends a high pulse to activate the coil the user can then activate the solenoid with the bat button. The PIC only sends a .5 second pulse, which is a little more time then is needed to pitch the ball. The PIC is activated to send this pulse when the pitching arm hits the lever switch located on the stopping bar in the back of the game (See pitching above). |
In order to power our solenoid and motor we needed external power. We used the 9.6V rechargeable batteries found in the lab kits. The first battery is permanently connected to the pitching motor as well as in series with the second battery. The two batteries in series are connected to the solenoid via a [http://pdf1.alldatasheet.com/datasheet-pdf/view/105974/ETC/RSB5S.html RSB52 relay]. When the PIC sends a high pulse to activate the coil the user can then activate the solenoid with the bat button. The PIC only sends a .5 second pulse, which is a little more time then is needed to pitch the ball. The PIC is activated to send this pulse when the pitching arm hits the lever switch located on the stopping bar in the back of the game (See pitching above). |
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Ideally, when the pitch button is activated it will turn the arm upwards and both activate the switch and pitch the ball. The relay will come on allowing the player to complete the loop on the solenoid with the bat button. Once the half second delay ends the relay closes, which means the user can no longer activate the bat. This way only one swing is allowed per pitch. |
Ideally, when the pitch button is activated it will turn the arm upwards and both activate the switch and pitch the ball. The relay will come on allowing the player to complete the loop on the solenoid with the bat button. Once the half second delay ends the relay closes, which means the user can no longer activate the bat. This way only one swing is allowed per pitch. |
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<br clear=all> |
<br clear=all> |
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=== |
===Scoreboard Circuitry=== |
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For the scoreboard we used two seven segment displays [http://media.digikey.com/pdf/Data%20Sheets/Lite-On%20PDFs/LTD-4708JS.pdf LTD-4708JS] and a [http://www.standardics.nxp.com/products/hef/datasheet/hef4543b.pdf HEF 4543B] decoder chip for each. We used pins RD0-RD5 and RB0-RB5 on the PIC for the two displays. The connections are the same as those outlined [http://hades.mech.northwestern.edu/wiki/index.php/Controlling_a_seven_segment_display here.] The scoreboard also had two LEDs for counting the number of outs. |
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[[Image:Baseball_Scoreboard_Circuitry.jpg|left|Scoreboard circuitry, two seven-segment displays and two LEDs for outs|thumb|300px]] |
[[Image:Baseball_Scoreboard_Circuitry.jpg|left|Scoreboard circuitry, two seven-segment displays and two LEDs for outs|thumb|300px]] |
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<br clear=all> |
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===Base and Out LEDs=== |
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For the three bases and the two out indicators we used the same bright red LEDs. We attached them in series with a 100 Ohm resistor and sent a signal from the PIC. Once a man was on base, or an out was indicated the PIC would output a digital high signal. Below is an example of a base LED. |
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[[Image:Baseball_Base_LED.jpg|left|A Base LED|thumb|300px]] |
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<br clear=all> |
<br clear=all> |
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==PIC Code== |
==PIC Code== |
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[[media: |
[[media:baseball_fullcode.c|Link to full code]] |
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<b>General outline of code:</b> |
<b>General outline of code:</b> |
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Line 124: | Line 113: | ||
<pre> |
<pre> |
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#include <18f4520.h> |
#include <18f4520.h> |
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#DEVICE ADC=8 |
#DEVICE ADC=8 |
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#fuses HS,NOLVP,NOWDT,NOPROTECT |
#fuses HS,NOLVP,NOWDT,NOPROTECT |
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#use delay(clock=20000000) |
#use delay(clock=20000000) |
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#define FIRSTBASE PIN_C0 |
#define FIRSTBASE PIN_C0 //Output to base LEDs |
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#define SECONDBASE PIN_C1 |
#define SECONDBASE PIN_C1 |
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#define THIRDBASE PIN_C2 |
#define THIRDBASE PIN_C2 |
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#define SINGLE_SENSOR PIN_A0 |
#define SINGLE_SENSOR PIN_A0 //Analog input pins for each sensor |
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#define DOUBLE_SENSOR PIN_A1 |
#define DOUBLE_SENSOR PIN_A1 |
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#define TRIPLE_SENSOR PIN_A2 |
#define TRIPLE_SENSOR PIN_A2 |
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#define HR_SENSOR PIN_A3 |
#define HR_SENSOR PIN_A3 |
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#define OUT_SENSOR PIN_A5 |
#define OUT_SENSOR PIN_A5 |
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#define OUT1 PIN_E1 |
#define OUT1 PIN_E1 //Output to scoreboard out LEDs |
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#define OUT2 PIN_E2 |
#define OUT2 PIN_E2 |
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#define BATSWITCH PIN_D7 |
#define BATSWITCH PIN_D7 //Output to enable bat |
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void singlehit(); |
void singlehit(); |
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void doublehit(); |
void doublehit(); |
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void triplehit(); |
void triplehit(); |
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Line 151: | Line 140: | ||
int8 team1score=0, remainder1=0, tensdigit1=0; |
int8 team1score=0, remainder1=0, tensdigit1=0; |
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int8 team2score=0, remainder2=0, tensdigit2=0; |
int8 team2score=0, remainder2=0, tensdigit2=0; |
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int8 team1=1, team2=0; // |
int8 team1=1, team2=0; //Team 1 starts at bat |
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int8 bases=0; |
int8 bases=0; |
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int8 singleadvance[8]={1,3,5,7,9,11,13,15}; |
int8 singleadvance[8]={1,3,5,7,9,11,13,15}; //Look at diagram of array initialization |
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int8 doubleadvance[8]={2,6,10,14,10,14,18,22}; |
int8 doubleadvance[8]={2,6,10,14,10,14,18,22}; |
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int8 tripleadvance[8]={4,12,12,20,12,20,20,28}; |
int8 tripleadvance[8]={4,12,12,20,12,20,20,28}; |
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int8 hradvance[8]={8,16,16,24,16,24,24,32}; |
int8 hradvance[8]={8,16,16,24,16,24,24,32}; |
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Line 171: | Line 160: | ||
while(TRUE){ |
while(TRUE){ |
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while(innings<3){ |
while(innings<3){ //Three inning game |
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while(team1==1) { |
while(team1==1) { //Team 1 at bat |
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set_adc_channel(5); |
set_adc_channel(5); |
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Line 180: | Line 169: | ||
if (stopswitch>200){ |
if (stopswitch>200){ |
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output_high(BATSWITCH); |
output_high(BATSWITCH); |
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delay_ms(500); // |
delay_ms(500); //Time for player to swing |
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output_low(BATSWITCH); |
output_low(BATSWITCH); |
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} |
} |
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set_adc_channel(0); |
set_adc_channel(0); //Read from analog inputs to detect ball |
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delay_us(10); |
delay_us(10); |
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singlesensor = read_adc(); |
singlesensor = read_adc(); |
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Line 201: | Line 190: | ||
outsensor = read_adc(); |
outsensor = read_adc(); |
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if (singlesensor > 100) { // |
if (singlesensor > 100) { //Call appropriate function depending on where ball dropped |
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singlehit(); |
singlehit(); |
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delay_ms(1000); |
delay_ms(1000); //This delay prevents the program from misreading the sensor, for example, |
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} //if the ball jiggles and triggers the sensor twice in a short period of time |
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} |
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if (doublesensor > 100) { |
if (doublesensor > 100) { |
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doublehit(); |
doublehit(); |
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Line 222: | Line 211: | ||
} |
} |
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displayscore(); |
displayscore(); //Update scoreboard |
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} |
} |
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while(team2==1) { |
while(team2==1) { //Team 2 at bat |
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set_adc_channel(5); |
set_adc_channel(5); |
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if (stopswitch>200){ |
if (stopswitch>200){ |
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output_high(BATSWITCH); |
output_high(BATSWITCH); |
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delay_ms(500); |
delay_ms(500); |
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output_low(BATSWITCH); |
output_low(BATSWITCH); |
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} |
} |
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Line 254: | Line 243: | ||
outsensor = read_adc(); |
outsensor = read_adc(); |
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if (singlesensor > 100) { |
if (singlesensor > 100) { |
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singlehit(); |
singlehit(); |
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delay_ms(1000); |
delay_ms(1000); |
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Line 279: | Line 268: | ||
} |
} |
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innings=innings+1; |
innings=innings+1; //Next inning |
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} |
} |
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team1score=0; |
team1score=0; //New game after three innings |
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team2score=0; |
team2score=0; |
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bases=0; |
bases=0; |
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innings=0; |
innings=0; |
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} |
} |
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} |
} |
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Line 298: | Line 289: | ||
For the single, double, triple, and home run functions we used different arrays that were initialized at the beginning of the program. The values in these arrays are explained through the following diagram: |
For the single, double, triple, and home run functions we used different arrays that were initialized at the beginning of the program. The values in these arrays are explained through the following diagram: |
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[[Image:baseball_array_explanation2.jpg|left||thumb| |
[[Image:baseball_array_explanation2.jpg|left|Diagram of array initialization|thumb|700px]] |
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<br clear=all> |
<br clear=all> |
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In this example for a double, the left side of the figure shows the eight possible base configurations. The first three bits represent first, second and third base (a 1 indicates a runner on base). After a double the baserunners |
In this example for a double, the left side of the figure shows the eight possible base configurations. The first three bits represent first, second and third base (a 1 indicates a runner on base). After a double the baserunners advance two bases as shown on the right side of the figure. We kept track of runs scored by using the five bits on the left. At the beginning of the program arrays were initialized for each type of hit. For a double, the initialization would be: |
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int8 doubleadvance[8]={2,6,10,14,10,14,18,22}; |
int8 doubleadvance[8]={2,6,10,14,10,14,18,22}; |
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⚫ | This way we could use the global variable, <i>bases</i>, to call up the appropriate value from each array. To determine the number of runs scored, we simply shifted the bits to the right by three places (>>3). To update the position of the baserunners, we had to clear all the bits except the first three. This was accomplished by shifting the bits to the left five places (<<5) then shifting them to the right by five (>>5) places. The result was the new value for <i>bases</i>. |
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⚫ | This way we could use the global variable, <i> |
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Line 316: | Line 305: | ||
int runsadded, basetemp; |
int runsadded, basetemp; |
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runsadded = singleadvance[bases]>>3; |
runsadded = singleadvance[bases]>>3; //Determine run scored |
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basetemp=singleadvance[bases]<<5; |
basetemp=singleadvance[bases]<<5; |
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bases=basetemp>>5; |
bases=basetemp>>5; //Update baserunners' positions |
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output_C(bases); |
output_C(bases); //Light up appropriate bases |
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if(team1==1){ |
if(team1==1){ //Update score |
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team1score=team1score+runsadded; |
team1score=team1score+runsadded; |
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} |
} |
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Line 414: | Line 403: | ||
outs=outs+1; |
outs=outs+1; |
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if (outs==3 && team1==1){ // |
if (outs==3 && team1==1){ //Switch to Team 2 at bat |
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team1=0; |
team1=0; |
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team2=1; |
team2=1; |
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outs=0; |
outs=0; |
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bases=0; |
bases=0; //Clear the bases |
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output_low(FIRSTBASE); |
output_low(FIRSTBASE); |
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output_low(SECONDBASE); |
output_low(SECONDBASE); |
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Line 424: | Line 413: | ||
} |
} |
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if (outs==3 && team2==1){ // |
if (outs==3 && team2==1){ //Switch to Team 1 at bat |
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team2=0; |
team2=0; |
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team1=1; |
team1=1; |
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Line 442: | Line 431: | ||
<pre> |
<pre> |
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void displayscore() { |
void displayscore() { |
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remainder1 = team1score % 10; |
remainder1 = team1score % 10; |
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tensdigit1 = (team1score - remainder1)/10; |
tensdigit1 = (team1score - remainder1)/10; |
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output_b(remainder1 & 15); |
output_b(remainder1 & 15); |
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output_high(PIN_B4); |
output_high(PIN_B4); //Activate ones digit |
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delay_ms(2); |
delay_ms(2); |
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output_b(tensdigit1 & 15); |
output_b(tensdigit1 & 15); |
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output_high(PIN_B5); |
output_high(PIN_B5); //Activate tens digit |
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delay_ms(2); |
delay_ms(2); |
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Line 464: | Line 453: | ||
delay_ms(2); |
delay_ms(2); |
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if (outs==0 || outs==3){ // |
if (outs==0 || outs==3){ //Out LEDs on scoreboard |
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output_low(OUT1); |
output_low(OUT1); |
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output_low(OUT2); |
output_low(OUT2); |
Latest revision as of 15:10, 23 March 2008
Team Members
Ming Lee Chow: Biomedical Engineering Class of 2008
Jeremy Klem: Mechanical Engineering Class of 2008
Overview
The goal of this project was to make an interactive baseball game inspired by pinball. There is a solenoid-powered bat and a pitching mechanism that utilizes a motor and lever arm setup. Both of these are controlled by buttons so that two people can play against each other. The game has targets for a single, double, triple, and home run, with a simple photodiode-phototransistor circuit to sense the ball. There are LEDs to light up each base as well as a scoreboard containing two seven-segment displays and LEDs for outs.
This page will describe the mechanical design, electrical design, and code for the project.
Mechanical Design
Play Field and Housing
The general concept is to have a slanted surface similar to a pinball machine. The ball will roll down and the user will try to hit it back up into a single, double, triple or homerun. These "hits" have dampening backstops and milled down grooves to channel the ball into a hole where a sensor is placed. If none of these are hit then the ball rolls back down towards the bat and into an out hole. This was done to limit the number of holes and sensor we would need to create. There are rails along the play field so the ball will not fly off. Underneath, there is a recess, which is an oppositely slanted board to channel the ball back to the pitching apparatus. The housing has sides to mount the bat button and keep the ball from sliding out of the recess. A acrylic sheet was used to wrap around the back as the rear wall. Holes were cut to allow pitching and scoreboard display.
Bat
The Bat was fashioned out of wood on the band saw and sanded to a finish. Two holes were drilled: one to act as an anchoring pivot point and the other to be attached to an actuator. A Spring Return Solenoid, run on two 9.6V rechargeable batteries in series, was used to actuate the bat. The user interface was a simple push button usually stocked in the lab. This button was located on the right side of the game similar to where pinball buttons are located.
In order to make the game more like baseball we set up a system to only allow the user to swing once per pitched ball. To learn more about this look below to Bat Relay.
Pitcher
To actuate the ball up to a position to be "pitched" a RS385 motor and scooping arm were used. The motor was hooked up to a 9.6V battery found in the kits. Once activated the arm turns upwards until hitting a static bar. Attached to the bar is a lever switch which sends a pulse to the PIC telling it that a pitch has been thrown. The momentum of the ball would shoot it out of the scoop where a curved ramp would project it onto the play field. The motor is attached to a simple push button so another player can pitch creating a more interactive game. The arm, bar and ramp were made out of scrap sheet metal found in the machine shop.
Electrical Design
PIC Schematic
Circuit Diagram
Sensor
Pitcher and Bat
LED Circuit
Seven Segment Display
Photodiode/Phototransistor Sensor
An IR optical sensor was used to detect the ball falling through a hole. The transistor will be receive a large amount of infrared radiation constantly, until a ball falls through. The obstruction will send a pulse to the PIC and either an out, single, double, triple or homerun will be executed.
Bat Relay & Power Supplies
In order to power our solenoid and motor we needed external power. We used the 9.6V rechargeable batteries found in the lab kits. The first battery is permanently connected to the pitching motor as well as in series with the second battery. The two batteries in series are connected to the solenoid via a RSB52 relay. When the PIC sends a high pulse to activate the coil the user can then activate the solenoid with the bat button. The PIC only sends a .5 second pulse, which is a little more time then is needed to pitch the ball. The PIC is activated to send this pulse when the pitching arm hits the lever switch located on the stopping bar in the back of the game (See pitching above).
Ideally, when the pitch button is activated it will turn the arm upwards and both activate the switch and pitch the ball. The relay will come on allowing the player to complete the loop on the solenoid with the bat button. Once the half second delay ends the relay closes, which means the user can no longer activate the bat. This way only one swing is allowed per pitch.
Scoreboard Circuitry
For the scoreboard we used two seven segment displays LTD-4708JS and a HEF 4543B decoder chip for each. We used pins RD0-RD5 and RB0-RB5 on the PIC for the two displays. The connections are the same as those outlined here. The scoreboard also had two LEDs for counting the number of outs.
Base and Out LEDs
For the three bases and the two out indicators we used the same bright red LEDs. We attached them in series with a 100 Ohm resistor and sent a signal from the PIC. Once a man was on base, or an out was indicated the PIC would output a digital high signal. Below is an example of a base LED.
PIC Code
General outline of code:
- Detect switch on pitching mechanism to enable bat
- Detect ball dropping through sensors
- Call appropriate function (single, double, triple, home run, or out)
- Update position of baserunners and light up base LEDs
- Display updated score and outs on scoreboard
- Switch teams at three outs
- End game after three innings
Variable and function definitions:
#include <18f4520.h> #DEVICE ADC=8 #fuses HS,NOLVP,NOWDT,NOPROTECT #use delay(clock=20000000) #define FIRSTBASE PIN_C0 //Output to base LEDs #define SECONDBASE PIN_C1 #define THIRDBASE PIN_C2 #define SINGLE_SENSOR PIN_A0 //Analog input pins for each sensor #define DOUBLE_SENSOR PIN_A1 #define TRIPLE_SENSOR PIN_A2 #define HR_SENSOR PIN_A3 #define OUT_SENSOR PIN_A5 #define OUT1 PIN_E1 //Output to scoreboard out LEDs #define OUT2 PIN_E2 #define BATSWITCH PIN_D7 //Output to enable bat void singlehit(); void doublehit(); void triplehit(); void homerun(); void out(); void displayscore(); int8 singlesensor, doublesensor, triplesensor, hrsensor, outsensor; int8 outs=0, innings=0, stopswitch; int8 team1score=0, remainder1=0, tensdigit1=0; int8 team2score=0, remainder2=0, tensdigit2=0; int8 team1=1, team2=0; //Team 1 starts at bat int8 bases=0; int8 singleadvance[8]={1,3,5,7,9,11,13,15}; //Look at diagram of array initialization int8 doubleadvance[8]={2,6,10,14,10,14,18,22}; int8 tripleadvance[8]={4,12,12,20,12,20,20,28}; int8 hradvance[8]={8,16,16,24,16,24,24,32};
Main function for baseball game:
void main() { setup_adc_ports(AN0_TO_AN5); setup_adc(ADC_CLOCK_INTERNAL); while(TRUE){ while(innings<3){ //Three inning game while(team1==1) { //Team 1 at bat set_adc_channel(5); delay_us(10); stopswitch = read_adc(); if (stopswitch>200){ output_high(BATSWITCH); delay_ms(500); //Time for player to swing output_low(BATSWITCH); } set_adc_channel(0); //Read from analog inputs to detect ball delay_us(10); singlesensor = read_adc(); set_adc_channel(1); delay_us(10); doublesensor = read_adc(); set_adc_channel(2); delay_us(10); triplesensor = read_adc(); set_adc_channel(3); delay_us(10); hrsensor = read_adc(); set_adc_channel(4); delay_us(10); outsensor = read_adc(); if (singlesensor > 100) { //Call appropriate function depending on where ball dropped singlehit(); delay_ms(1000); //This delay prevents the program from misreading the sensor, for example, } //if the ball jiggles and triggers the sensor twice in a short period of time if (doublesensor > 100) { doublehit(); delay_ms(1000); } if (triplesensor > 100) { triplehit(); delay_ms(1000); } if (hrsensor > 100) { homerun(); delay_ms(1000); } if (outsensor > 100) { out(); delay_ms(1000); } displayscore(); //Update scoreboard } while(team2==1) { //Team 2 at bat set_adc_channel(5); delay_us(10); stopswitch = read_adc(); if (stopswitch>200){ output_high(BATSWITCH); delay_ms(500); output_low(BATSWITCH); } set_adc_channel(0); delay_us(10); singlesensor = read_adc(); set_adc_channel(1); delay_us(10); doublesensor = read_adc(); set_adc_channel(2); delay_us(10); triplesensor = read_adc(); set_adc_channel(3); delay_us(10); hrsensor = read_adc(); set_adc_channel(4); delay_us(10); outsensor = read_adc(); if (singlesensor > 100) { singlehit(); delay_ms(1000); } if (doublesensor > 100) { doublehit(); delay_ms(1000); } if (triplesensor > 100) { triplehit(); delay_ms(1000); } if (hrsensor > 100) { homerun(); delay_ms(1000); } if (outsensor > 100) { out(); delay_ms(1000); } displayscore(); } innings=innings+1; //Next inning } team1score=0; //New game after three innings team2score=0; bases=0; innings=0; } }
Functions for single, double, triple, home run, and out:
For the single, double, triple, and home run functions we used different arrays that were initialized at the beginning of the program. The values in these arrays are explained through the following diagram:
In this example for a double, the left side of the figure shows the eight possible base configurations. The first three bits represent first, second and third base (a 1 indicates a runner on base). After a double the baserunners advance two bases as shown on the right side of the figure. We kept track of runs scored by using the five bits on the left. At the beginning of the program arrays were initialized for each type of hit. For a double, the initialization would be:
int8 doubleadvance[8]={2,6,10,14,10,14,18,22};
This way we could use the global variable, bases, to call up the appropriate value from each array. To determine the number of runs scored, we simply shifted the bits to the right by three places (>>3). To update the position of the baserunners, we had to clear all the bits except the first three. This was accomplished by shifting the bits to the left five places (<<5) then shifting them to the right by five (>>5) places. The result was the new value for bases.
Single:
void singlehit(){ int runsadded, basetemp; runsadded = singleadvance[bases]>>3; //Determine run scored basetemp=singleadvance[bases]<<5; bases=basetemp>>5; //Update baserunners' positions output_C(bases); //Light up appropriate bases if(team1==1){ //Update score team1score=team1score+runsadded; } if(team2==1){ team2score=team2score+runsadded; } }
Double:
void doublehit() { int runsadded, basetemp; runsadded = doubleadvance[bases]>>3; basetemp=doubleadvance[bases]<<5; bases=basetemp>>5; output_C(bases); if(team1==1){ team1score=team1score+runsadded; } if(team2==1){ team2score=team2score+runsadded; } }
Triple:
void triplehit() { int runsadded, basetemp; runsadded = tripleadvance[bases]>>3; basetemp=tripleadvance[bases]<<5; bases=basetemp>>5; output_C(bases); if(team1==1){ team1score=team1score+runsadded; } if(team2==1){ team2score=team2score+runsadded; } }
Home run:
void homerun() { int runsadded, basetemp; runsadded = hradvance[bases]>>3; basetemp=hradvance[bases]<<5; bases=basetemp>>5; output_C(bases); if(team1==1){ team1score=team1score+runsadded; } if(team2==1){ team2score=team2score+runsadded; } }
Out:
void out() { outs=outs+1; if (outs==3 && team1==1){ //Switch to Team 2 at bat team1=0; team2=1; outs=0; bases=0; //Clear the bases output_low(FIRSTBASE); output_low(SECONDBASE); output_low(THIRDBASE); } if (outs==3 && team2==1){ //Switch to Team 1 at bat team2=0; team1=1; outs=0; bases=0; output_low(FIRSTBASE); output_low(SECONDBASE); output_low(THIRDBASE); } }
Function for scoreboard display:
void displayscore() { remainder1 = team1score % 10; tensdigit1 = (team1score - remainder1)/10; output_b(remainder1 & 15); output_high(PIN_B4); //Activate ones digit delay_ms(2); output_b(tensdigit1 & 15); output_high(PIN_B5); //Activate tens digit delay_ms(2); remainder2 = team2score % 10; tensdigit2 = (team2score - remainder2)/10; output_d(remainder2 & 15); output_high(PIN_D4); delay_ms(2); output_d(tensdigit2 & 15); output_high(PIN_D5); delay_ms(2); if (outs==0 || outs==3){ //Out LEDs on scoreboard output_low(OUT1); output_low(OUT2); } if (outs==1) { output_high(OUT1); } if (outs==2){ output_high(OUT1); output_high(OUT2); } }
Results and Reflections
Overall, our baseball project was successful, the bat performed reliably and with its range of motion it was possible to hit all four targets. The pitching mechanism was effective; however, we did have a few cases where the lever arm would get stuck or the ball would drop out. To improve this the lever arm could be smoothed out and a piece of tubing could replace the metal sheet. This should make the pitching more reliable.
The base LEDs and the scoreboard functioned properly. The four sensors for single, double, triple and home run detected the ball consistently and advanced the baserunners correctly. One major problem we found was that occasionally the program missed reading an out. This is due to the timing of the program, so that when the ball fell through the out sensor the program would not be reading from the analog input at that time. We tried to adjust the 500ms delay when the player can swing (see Code), but the program would still miss reading the sensor. One possible way to fix this is to use an interrupt triggered by a digital input pin.
Originally we intended for the game to pitch automatically using another relay circuit to the pitching motor. The program would then activate the pitching mechanism at random times. We ended up using a button for the pitching because it would be more interactive and allow two people to play against each other.