FR2470404A1 - Timing circuit for pistol shooting - includes oscillator and divider chain producing pips at timed intervals - Google Patents

Abstract

The timing circuit includes an oscillator producing a signal at 16384 Hz. This is fed via a 14 stage divider and logic gate system to produce signals at specific frequencies to control the circuits operation - these are at 1, 1024 and 256 Hz. The output signals produced are used to guide the pistol shooter, providing two timed intervals. At the start of the first time a signal of 1024 Hz is produced. This 'pip' lasts for about 0.3 s. At the end of the pip a permanent signal of 256 Hz starts indicating the waiting time. When this interval finishes a second 1024 Hz pip is produced lasting again about 0.3 s. An interval for firing then follows, during which no sound is produced at all. Finally a third pip indicates that the timing is completed. This arrangement is in accordance with international regulations for pistol shooting.

Description

 The present invention relates to devices of the timer n type "whose purpose is to generate an acoustic signal at the start and at the end of a time determined by the user.

 It is more particularly intended for the individual training of target pistol shooters. In this sporting discipline, in fact, shooting time is regulated according to international standards.

The characteristic of the present invention resides in its possibility of successively delivering two times chosen by the user, in the following form
I - At the start of the 1st time, a signal at I024 HZ
warns the shooter. The duration of this "beep" is
About 0.3 seconds.

2 - Following this '1 beep', a permanent signal to
256 HZ materializes the so-called "waiting time".

3 - This waiting time having elapsed, a second beep at
I024 HZ and always about 0.3 seconds gives
start of shooting time. Meanwhile, no
acoustic signal.

4 - At the end of this shooting time, a third "beep",
still at I024 HZ, warns the shooter of the end of
the time delay.

I1 should be noted the possibility offered to have, at the option of the user, successively, a "waiting time" then a "shooting time" in an uninterrupted manner, the "beep" separating each of these times. This is particularly interesting for the discipline known as "duel shooting".

In the present invention, entirely electronic, the time delay is of the digital type.

This timing principle is known, so research has focused on adapting this principle to the particular use mentioned above and on the following points
- I iacility of implementation by the user;
- 2 Ease and precision of adjustment, and reliability;
- 3 Minimum consumption;
- 4 Minimum dimensions;
TECHNICAL DESCRIPTION: (refer to figure I
Time delay s
First we have a Resistance type oscillator
Capacity which provides us with a frequency of I6 384 hertz.

This oscillator is built around two NAND type gates. The resistance of the R / C circuit is adjustable.

The signal from this oscillator enters a divider circuit with 14 stages, the utility of which is triple i
- Provide a signal to I HZ
- Provide a signal to I024 HZ (for the "beep");
- Provide a signal at 256 HZ (for the waiting time).

The signal at I HZ is directed, on the one hand, to a J / K type rocker (NOI) and, on the other hand, to a binary down counter, through a "NAND" gate
The aim of the J / K type rocker is, according to the time programming applied to it, to "trap" one pulse out of two, which are directed towards the. binary counter, so double the time
I1 it should be noted that this arrangement avoids a second down counter, without requiring an additional circuit since in an integrated circuit there are 2 J / K rockers
We will see below the usefulness of the second rocker
Also note the double purpose of the "NAND" gate which is located between the I HZ output of the divider and
the input of the down-counter
I - Allow or not, depending on the state of the downcounter,
I HZ signal to pass. (when we have finished the
down counting, the down counter blocks the entry of
pulses)
2 - Make the down counter only advance on
the falling edge of the signal from the divider.

As far as programming is concerned, it is done through a diode matrix on the down-counter inputs which are provided for this. Whether or not to apply the programming on the J / K rocker doubles the time or not,
as previously explained
This for the timing part itself.

Additional circuits:
We have, first of all, a double monostable
One of these monostables, whose tilting time
is of the order of I5 <second, for the purpose
By its direct output
- Resetting the divider to "0" (ie the ini
tialization);
- The loading of the down counter by the pro signal
grammage present on its inputs during these
I5 y seconds
- The change of state of the J / K rocker (NO 2)
whose usefulness we will see later
By its inverting output
Trigger the second monostable.

 This first monostable is controlled by a signal from the oscillator through a "NAND" gate. This command can only act if the signal from the down counter is at the low level (down counter at level O on its outputs), the down counting being finished.

 The second monostable, whose tilting time is of the order of 0.3 seconds, aims to allow, in its "working" state, the signal at I024 HZ from the divider to reach, through a combinational circuit , the output and ... the earpiece, while "blocking" the signal at 256 HZ.

The task of this monostable is therefore to deliver the "bit" at the start and end of the time delay.

 I1 is triggered either by the signal from the down-counter (end of counting) or by the signal from the first monostable (start of down-counting).

There is also, in the auxiliary circuit, a second J / K rocker (the N02) which receives the signal from the first monostable as we have seen previously. Its role is as follows
- In one of its states, it authorizes the passage of the signal at 256 HZ towards the output (this signal must also have the authorization of the second monostable to reach the output).

I1 makes appear at the input of the binary down-counter, via the diode matrix, the formulation corresponding to the so-called "waiting" time delay (with signal at 256 HZ). I1 finally allows the signal from the oscillator to influence the input of the first monostable through one or turkey
- In the other of its states, it places at the entry of the down-counter, still through the diode matrix, the formulation corresponding to the second so-called "firing" delay and traps the signal at 256 HZ as well as the signal from of the oscillator (the latter will therefore no longer be able to trigger the first monostable).

The role of this circuit is therefore to alternate the so-called "waiting time" and the so-called "shooting time" and to ensure that the waiting time is necessarily followed by the shooting time.

 The last additional circuit is the combinatory circuit which receives the signal at 1024 HZ, the signal at 256 HZ, the authorizations of the second monostable and of the second J / K rocker.

It should be noted that this combinational circuit directly attacks, through a small capacity, the earpiece.

TECHNICAL OPERATION:
As it appears in the technical description, the rest position of the system is the end of the down counting position, since then the down counter blocks the pulses at I HZ applied on its input and places the monostable "I" in the receiving position.

Starting from this "rest" position, it is noted that a closing (temporary or not) of the switch "I" causes the triggering of the monostable "I", allowing the signal from the oscillator to pass. This changes the state of the J / K rocker switch "2", which therefore presents the information of the 1st time delay on the down-counter and allows the signal to pass to 256 HZ. The transfer time of this circuit being very low, the binary timing information can be stored in the down counter before the monostable "I" returns to its rest position. The down counter "loads n, it prevents the monostable" I " to receive new trigger pulses and therefore to remain in the "work" position
When this monostable returns to its rest position, it locks the inputs of the down-counter, suppresses the initialization of the divider on 14 stages and, therefore, starts the timer. It also triggers the monostable "2" (beep). beep is triggered just at the start of the timer and that it has no influence on the duration of the latter.

 During this first delay and the start beep being finished, the signal at 256 HZ will pass to the earpiece.

At the end of this first time, the down counter arriving at "O" blocks the signal at I HZ arriving at its input, triggers
the monostable "2" of the "beep" and allows the monostable "I" to
shift to work position, when a pulse occurs
sion on its entry. This impulse will also happen
since the state of the J / K rocker "2" allows it.

The cycle will therefore start again, but this time with the information
second timer, J / K rocker "2"
having changed state.

During this second delay, the signal at 256 HZ
will not pass, the J / K rocker "2" not allowing it
At the end of this second time, the process of the end of
first time occurs, except the triggering of the
monostable "I". This, in fact, can only be triggered
if the switch "I" is closed or if the rocker J / K "2"
is on the position of the first time delay.

The system will therefore stop and be in the standby position.

To successively obtain "waiting time" and "time
firing ", just leave the switch" I "closed.

It should be noted that the arrangement used avoids
faults due to "bounces" of switch "I".

The system can be shut down by acting on the input
"reset to zero" of the down-counter. This is interesting in case
error on the time display.

Special operation of the J / K NO I rocker
This rocker changes state on the rising edge of the pulse at I HZ, if the programming allows its rocking.

We see that, as it traps, in one of its states, the information entering the down counter, only one pulse out of two will penetrate and activate the latter. As a reminder, the down counter is only influenced by the falling edge of the signal at I HZ
Special case of the waiting time O second:
In this particular case, the loading of the counter die being "O", it does not change state. The duration of the working time of the monostable "I" being less than the time between two pulses coming from the oscillator, when a second pulse arrives from the oscillator, the monostable "I" will therefore trigger again. The duration of time "O" will therefore correspond to the period "T" of the oscillator, that is to say approximately 60 <seconds, that is to say negligible.

To finish this explanation, it remains to say:
I - The signal attacking the downcounter being of I HZ,
the latter will switch at the rate of seconds.

2 - This structure limits the number of
circuits. Please note that if, in the
present invention, times of greater duration
at 20 seconds have not been retained, just
add a down counter to get them (up to
5I2 seconds.

3 - This structure allowing the use of circuits
C.MOS ", we get very low consumption
(less than I mA; therefore a long service life of
the battery. The latter could be of current type.

External appearance and operation seen by the user
One of the possible presentations is the one attached to this presentation (Figure 2
On this presentation, we have a small metal case (I20 x 80 x 35 m / m).

 On the upper part of this case, we find an "on-off" switch, a switch with 3 stable positions for waiting times of 0.3 and 7 seconds, finally a switch with 2 stable positions and an unstable for the start of timers. A six-position switch displays the following firing times: 3, 4, 6, 8, 10 and 20 seconds. Finally, a jack allows you to connect the earpiece.

For the user, it suffices to switch on, to display the times, and a press on the "start" switch starts the time delay. This switch allows either a single cycle "waiting time - firing time n when using its" unstable "position, or a cycle continuity in its" stable "position. The" rest position being the middle position .

The headphone used is of current type with an impedance of 8 ohms. It is possible to use other types of headphones; in particular, a 2000 ohm impedance listener will give a stronger signal.

 Changing the battery (9 volts) in this case is easy: just open the case. The duration of this battery is at least 300 hours. When this becomes too weak, the signal strength decreases significantly, thus signaling its aging.

 It is enough to modify the frequency of the oscillator (by the adjustable resistance) to change all the times in the same proportion. This setting is accessible to the user.

Claims (4)

CLAIMS I - Digital timer more particularly intended for individual training for target pistol shooting, characterized in that it comprises an oscillator followed by a divider, a down-counter and circuits for shaping and referral. 2 - Timer according to claim I, characterized  by the fact that it generates two successive time delays,  one with an acoustic signal at 256 HZ, says "waiting" time, the other, silent, known as shot 3 - Timer according to claim I, characterized by the fact that the start and end of each timer are signaled by a "beep" at I024 HZ. 4 - Timer according to claims 2 and 3 character  laughed at by the use of a single oscillator, the signals  at 256 HZ and I024 HZ coming from the divider. 5 - Timer according to claim "I" characterized by  the use of a rocker (J / K "2") allowing to alter  ner the so-called waiting and firing times. 6 - Timer according to claim "5" characterized in that the J / K rocker "2" can be replaced by a  counter type "JOHNSON" allowing following the same  principle of sequencing a greater number of beats.