weapon is inaccurately aimed or is not aimed at a target of shots loaded into the counter upon start up is deterlight that is energized, the relatively high resistance of mined by the setting of switches S5-S12. Each time the the photocell 132 keeps the output line from amplifier trigger 144 of the target weapon is depressed, the shot 134 below the threshold of comparator 138, and the on line 156 goes high to decrement the counters 186 and target line 142 is then in a low state. 5 188. The number of shots remaining is displayed on the With continued reference to FIG. 5, the hand held digital displays 38 The number of display 194 is the least target weapon has a trigger switch 144 which is a single significant decimal digit and that on display 196 is the pole, double throw momentary contact switch. A nor- most significant digit. When the counters 186 and 188 mally closed contact 146 is connected with system are decremented to zero, indicating that the player has ground when the trigger switch 144 is not depressed. 10 expended all of the shots allotted to him, counter 188 When the trigger switch is depressed, a normally open generates a low pulse on the empty line 96. Until then, contact 148 connects with system ground. A pair of the empty line remains high.
NAND gates 150 and 152 form a latch circuit which The state of the two least significant digits of the
conditions the switch signal to eliminate the effects of ammunition counter is constantly monitored on sample
switch contact bounce. The normally closed contact 15 lines 198 and 200 which connect between counter 186
146 connects with one of the inputs of gate 150, and the and display driver 190. The purpose for this will subse
same input is also connected with +12 volts through a quently be explained.
resistor 153. Similarly, the normally open contact 148 is Referring now to FIG. 8, the target hits counter 32
connected with one of the inputs to gate 152. includes a CD4518B counter circuit 202 which is
The output signal from the latch circuit formed by 20 cleared by the start signal on line 66. A pair of display
gates 150 and 152 is applied via line 155 to a monostable drivers 204 and 206 decode the number in the hits
multivibrator 154 which is enabled by the end line 82. counter 202 and display it on digital displays 208 and
The Q output pin of circuit 154 is connected with a shot 210 which together form the hits display 34. The dis
line 156 which goes high each time the target weapon is play is cleared by the start line 76 which connects with
triggered. Line 156 connects with the second input of 25 display driver 204. The hit line 118 connects with the
AND gate 30. The output line of gate 30 is the hit line hits counter 202 and causes counter 202 to increment
118 which is applied to inverter 120 (see FIG. 6). each time line 118 goes high to indicate a hit on one of
FIG. 5 also shows a testing and adjustment circuit the target lamps 12.
which can be used to test the aim of the target weapon. FIG. 7 shows the hazard weapon control circuitry
A tone generator 158 is enabled when a high signal is 30 which includes a hazard cycle oscillator 212 enabled by
present on the on target line 142. The tone generator is a high signal on the end line 82. The output line 214 of
disabled when the on target line 142 is low, indicating the oscillator 212 cycles high for approximately five
that the weapon is inaccurately aimed. If a test switch seconds and then returns to the low state. Line 214
160 is closed, the tone generator 158 is disabled regard- connects with an inverter 216 and also with the input of
less of the state of the on target line 142. 35 a monostable multivibrator 218. The output side of
When the tone generator 158 is enabled, it provides a inverter 216 connects with a diode 220 to reverse bias
tone signal on its output line 162 which connects with the diode when the inverter output is high. The oppo
one input of an audio amplifier 164. A voltage divider site side of diode 220 connects with a conductor 221
formed by resistors 166 and 168 connects with the +12 which extends to a hazard warning tone generator 222.
volt source and applies a constant voltage to the other 40 Power is constantly available to line 221 so that the tone
input of amplifier 164. The inverting input of amplifier generator 222 is enabled when the output side of in
164 also connects with a hazard tone line 170. verter 216 is high to reverse bias diode 220 and is dis
The output side of amplifier 164 connects with the abled when the output side of the inverter is low to bases of a pair of transistors 172 and 174. A feed back forward bias the diode. The end line 82 is also conline 176 having a potentiometer 178 is connected be- 45 nected with line 221 through another diode 224 which is tween the transistors and extends to connection with reverse biased so long as the end line remains high. The the inverting input of the audio amplifier 164. Also hazard warning tone generator 222 is disabled whenconnected between the transistors 172 and 174 is a ever the end line 82 is in a low state regardless of the speaker line 180 which connects through a capacitor condition of the inverter 216.
182 with an audio speaker 184 having its other side 50 The output signal from the hazard warning tone genconnected with system ground. erator is applied through resistor 226 to the hazard tone
The ammunition counter and display circuitry shown line 170. As previously indicated in connection with in FIG. 9 includes a pair of counters 186 and 188 which FIG. 5, the hazard tone line 170 connects with the noncorrespond to the least significant digit and most signifi- inverting inut of the audio amplifier 164. cant digit, respectively. The total number of shots that 55 The Q output line 227 of the monostable multivibraare allotted during the course of the game can be set by tor 218 is connected as an active low input to a hazard the game operator by properly setting a series of weapon selector 228. The sample lines 198 and 200 are switches S5-S12 associated with the counters 186 and also connected with the hazard weapon selector 228. 188. A standard binary code is used for the switch set- The hazard weapon selector has four active low outtings. Signals indicative of the contents of the counters 60 puts. Three of the selector output lines 230, 232 and 234 186 and 188 are applied to display drivers circuits 190 are hazard enable lines which are active low lines that and 192 which decode the numbers in the counters and connect with inputs of respective NOR gates 236, 238 display the number of shots remaining to the player on and 240. The fourth output 242 of the hazard weapon digital displays 194 and 196 which together provide the selector is unconnected and serves as a "blank" fired shots remaining display 38. 65 from the hazard weapons, as will be explained more
The start line 76 connects with counter 186 and dis- fully,
play driver 190 to load the ammunition counter when The output side of NOR gate 236 is connected
the start pulse is generated. The predetermined number through an inverter 244 with one of the inverted inputs