Firearm Ammunition Counting System With Calibration Electronics and Visual Audible and Haptic Display Methods

Description

CROSS REFERENCE TO RELATED APPLICATIONS

Follow-up to U.S. provisional patent application 63/737,761 filed on Dec. 22, 2024.

OVERVIEW OF THE INVENTION

In various embodiments, the disclosed system determines ammunition round count inside a firearm magazine by measuring the force exerted by the magazine spring onto a deformable beam structure. Resistive sensing elements adhered to the beam detect force-induced strain, producing signals that correspond to follower position and therefore to the number of rounds in the magazine. The system may include calibration electronics, temperature-compensation components, bullet-change event sensors, and one or more microprocessors integrated into follower-based or baseplate-based configurations. The processed round-count information may be communicated by wired or wireless means to an external microprocessor for display through visual, audible, or haptic feedback methods.

EMBODIMENT LOCATIONS: FOLLOWER AND BASEPLATE INTEGRATION

The sensor may be positioned at different locations within the magazine depending on the embodiment. As shown in FIG. 1, a sensor (1) may be integrated between the follower (2) and the magazine spring (3) of a box-type magazine (4). In another embodiment, a sensor (5) may be positioned between the magazine spring (3) and the baseplate (6). Either configuration may be used separately or simultaneously in rifle applications (7) or adapted to pistols, shotguns, tube magazines, or fixed chambers. Integration may be accommodated for different bullet calibers (8), follower geometries (2), or spring characteristics (3). Any firearm system that uses a spring-loaded follower mechanism may utilize the disclosed sensor configuration.

FOLLOWER-MOUNTED SENSOR EMBODIMENTS

An embodiment in which the sensor is incorporated into the follower is shown in FIG. 2. The magazine spring (3) may apply force onto a rectangular bending beam (9). A set of resistive elements (10, 11, 12, 13) adhered to the beam detect strain generated by bending. Because follower position varies with compression of the spring, the force measured at the beam correlates to the number of rounds remaining. In one embodiment, the sensor module may include a sensor case body (14) positioned at or integrated with the follower of the magazine, and may further include electronic components such as an amplifier (15), a microprocessor (16), a temperature-sensing element such as a thermocouple (17), a wireless communication component such as a Bluetooth module (18), and a battery (19) or other power source.

The sensor may be pre-calibrated for different spring constants, environmental conditions, and ammunition calibers, or calibrated by the user. In some embodiments, calibration may occur automatically when the system detects an empty magazine. The sensor may be configured as a drop-in accessory for an existing magazine (4) or as an integrated feature in a dedicated “smart magazine” format. FIG. 2 illustrates one example configuration based on the design of the follower used in a PMAG 30 magazine for an AR-15 platform (7), although alternative shapes may be used so long as the fundamental bending-beam and resistive-element functions remain.

BASEPLATE-MOUNTED SENSOR EMBODIMENTS

As shown in FIG. 3, the sensor may alternatively be placed beneath the spring in the baseplate region (6). Resistive elements may be arranged in half-bridge or full-bridge Wheatstone configurations to enhance sensitivity. Pairs of compressive (10, 12) and tensile (11, 13) resistive elements may be adhered to the beam (9) using epoxy or other adhesives. The beam may be formed from a material suitable for the wide elastic range associated with spring forces—metal in one embodiment, or other materials as appropriate. The beam may be integrally formed with the sensor casing (20) or fabricated separately.

In one embodiment, the sensor module located at the baseplate may include a sensor case body (20) positioned at, adjacent to, or integrated with the baseplate of the magazine. The sensor module may include electronic components such as an amplifier (15), microprocessor (16), calibration input device (21), temperature-sensing element (17), wireless communication component (18), and a battery (19), or other electronics similar to those used in follower-mounted configurations. In certain embodiments, the baseplate configuration may further include external electrical access for passage of sensor signal or power through spring pins or other electrical connectors (22), and may incorporate alignment or retention features such as magnetic elements (23) to facilitate attachment of an external interface (24). The configuration may also include a calibration button (21) accessible from outside the magazine.

Another embodiment is shown in FIG. 4, where resistive sensors are adhered to a center beam (25). Here, the rectangular beam (26) may transfer bending loads into tensile strain across a the center beam (25). Sensors (27) adhered to the center beam detect this strain. Push-pin electrical interfaces (28) may be used to provide external electrical access and may be retained by clamps (29). A half-bridge configuration may include one unadhered resistive element to reduce thermal drift. Cross-section (30) shows dual-fulcrum support points (31), generating enhanced strain and increased robustness.

CROSS-SECTIONS AND SIGNAL AMPLIFICATION

FIG. 5-7 illustrate cross-sections of bending-beam elements for follower (32), baseplate (33), and modified (34) embodiments. Signals from the resistive elements may be amplified using a signal amplifier board (15). In one implementation, a chip such as an HX711 or similar device may measure the voltage potential across the resistive elements arranged in a Wheatstone bridge (35), as diagrammed in FIG. 8. Spring force (36) induces a moment on the beam (37) about a support point (38), generating strain on the sensing element (39), which produces the output signal (40).

PROCESSING AND WIRELESS COMMUNICATION

Signals may be transmitted from the amplifier to an embedded microprocessor (16). A wireless transmitter (18), such as a Bluetooth module, may communicate with an external processor (41), which may control a display (42), as in FIG. 9. In one embodiment, the external microprocessor (41) operates as a primary controller while the sensor microprocessor (16) functions as a secondary controller. The external microprocessor may transmit round-count data to an external display (42) via a wired (43) or wireless (44) connection.

DISPLAY AND WIRED COMMUNICATION OPTIONS

As shown in FIG. 10, a round-count display may be embedded directly into the magazine (45). The sensor output may reach the display via wired connections (46). An external collar (47) containing connectors (48) may be placed around the magazine to route power or data between internal and external electronics. Alternatively, connections may pass through the baseplate (22) using an external interface (24). The sensor may also receive input from a loaded-magazine sensor (49) configured to detect insertion of the magazine into the firearm. In various embodiments, the loaded-magazine sensor may be embedded in the rifle, in the magazine, or in another associated component, and may include a mechanical switch, proximity sensor, electrical contact, or other suitable device for indicating a loaded-magazine condition.

CALIBRATION COMPONENTS AND ENVIRONMENTAL COMPENSATION

In certain embodiments, the sensor (1) may include calibration and environmental-compensation electronics, which may incorporate a calibration input device (21), a temperature-sensing element such as a thermocouple (17), and one or more bullet-change state sensors. The calibration input device may be located on the baseplate (6) or on an external processor (41) and may communicate calibration commands to an internal microprocessor (16) through wired or wireless means. Power may be provided by a coin cell (19), a rechargeable battery, or another type of power source. In some embodiments, the thermocouple (17) may be thermally coupled to the bending beam (9), and its signal may be processed by an amplifier (15) or similar device. A protective casing, which may include shock-absorbing or water-resistant materials such as dielectric foam or rubber, may enclose the electronics for either follower-based or baseplate-based sensor configurations.

CALIBRATION PROCESS AND TEMPERATURE-DEPENDENT OPERATION

In one embodiment, calibration logic for the sensor is illustrated in FIG. 11. Calibration may be initiated when a user depresses and holds a calibration input device (50) for a predetermined duration. Upon initiation, the system may record a temperature value from the thermocouple (51) and compare this value to one or more previously stored temperature ranges in memory (52). If the sensed temperature falls within an existing range (53), previously stored calibration data may be used; otherwise, a new temperature entry may be recorded (54). The user may then load one or more rounds (55) into the magazine (4), and after the introduction of each round, the calibration input device (56) may be actuated to record the corresponding sensor signal (40). After a sufficient number of calibration points have been collected to establish a force-displacement relationship, the user may again hold the calibration input device (57), allowing the processor to compute and store a calibration-curve slope (58) or related calibration parameter (59). Calibration data may be associated with the sensed temperature (51), enabling temperature-dependent calibration curves. Upon successful calibration, the system may generate an output indication (60), such as a visual, audible, or haptic signal. In certain embodiments, each magazine may store or transmit a unique identifier or signal pattern, allowing an external display device (42) to distinguish among multiple magazines simultaneously.

ACTIVE AND PASSIVE MAGAZINE DETECTION

FIG. 12 illustrates detection of an active magazine (61) versus a passive magazine (62). A magazine may become active when a change in round count occurs, when slight follower depression is detected during insertion, when proximity to the display (42) is sensed, or when a loaded-magazine sensor (49) is engaged. In various embodiments, proximity may be detected using a Hall effect sensor, paired accelerometers in the sensor (1) and external processor (41), or other detection methods. Loaded-magazine sensors may include depressible plate buttons (63) or ball-bearing contact sensors (64) that complete or interrupt a circuit depending on the presence of a round, as shown in FIG. 13.

ROUND COUNT DETERMINATION

Round count may be computed by comparing sensor output (40) with a look-up table derived from calibration data (58) at the measured temperature (51). Computation may occur continuously, periodically, or when the sensor output changes by a threshold (e.g., half of one expected round increment). A discharge event sensor may confirm changes in round count. An empty-magazine sensor (63, 64) may detect when the magazine reaches zero rounds. The system may prompt recalibration or automatically recalibrate when an empty-magazine condition and an inconsistent resting sensor value are observed.

BULLET-CHANGE EVENT LOGIC

A logical flowchart for bullet-change event detection is shown in FIG. 14. Events may include manual reloading (65), chambering a round (66), chambering the last round (67), firing with rounds remaining (68), firing the last round (69), or a failure of the bolt to lock back (70). Sensors may include: a loaded magazine sensor (71), a discharge-event sensor (72), an empty-magazine sensor (73), and a cleared-chamber sensor (74). These may be implemented using mechanical switches, accelerometers, vibration signatures, or circuit-completion detectors.

USER NOTIFICATION METHODS

FIG. 16 illustrates visual (75), audible (76), and tactile (77) notification methods. Visual methods may include a magazine-mounted display (45), a rifle-mounted display (78), helmet HUD systems (79), eyewear (80) or scope, holographic, or red dot-integrated indicators (81, 82, 83), micro-LED indicators (84), or reticle-based patterns (85, 86, 87) as shown in FIGS. 17-18. Rifle-mounted displays may be attached to the firearm using the Picatinny rail interface (88) or any other suitable mounting structure. In various embodiments, the display may be secured using rail mounts, modular attachment systems, mechanical fasteners, magnetic or adhesive interfaces, or an integrated mounting feature of the rifle or optic. Audible methods may include patterns of tones relayed via headset or helmet systems. Tactile methods may include wearable vibration systems (89), pressure-based indicators, or grip-integrated haptic outputs. Notifications may represent exact round counts or simplified indicators (e.g., pulses decreasing with remaining rounds).

ELECTRICAL ARCHITECTURE

An example electrical diagram is shown in FIG. 19. Resistive elements (90, 91, 92, 93) may be arranged in a half or full-bridge configuration (94) and interfaced with a microcontroller (95) through an amplifier (96). Power may be supplied by a battery (97), a wireless-power receiver (98), wired connection, or other means. Sensor circuits (99) and receiving circuits (100) may include switches for power management. Signals (101) may be transmitted wirelessly (102) or via wired connections (103) to a receiving microcontroller (104). A thermocouple (105) may provide temperature data with the same amplifier as the force sensor (96) or through a separate amplifier (106). A calibration button may be integrated into either circuit (107, 108). Additional sensors may include an empty-magazine sensor (109), a loaded-magazine sensor (110), a cleared-chamber sensor (111), and a discharge-event sensor (112). Output devices (113) may support visual, audible, or haptic user feedback.

BACKGROUND

This disclosure relates generally to systems and devices for determining a quantity of unfired ammunition within a firearm magazine. In various applications, it may be desirable to identify the number of rounds remaining in a magazine during operation of a firearm. Accurately determining this information can be difficult due to the compact size of magazines, variations in magazine design, and environmental conditions encountered during firearm use. The systems and methods described herein address these and other challenges.

SUMMARY OF THE INVENTION

This disclosure describes systems, devices, and methods for determining a quantity of unfired ammunition within a firearm magazine. In various embodiments, a sensor assembly positioned within the magazine may detect forces associated with movement of a magazine spring or follower, and may generate signals indicative of a round count. The sensor assembly may include one or more strain-sensing elements coupled to a deformable structural member, and the resulting signals may be processed or amplified by associated electronics. Calibration components and environmental-compensation features may be incorporated to improve accuracy under variable operating conditions. The determined round count may be communicated to a user or to an external device through wired or wireless interfaces, and may be presented through visual, audible, or haptic feedback. Sensor assemblies may be located at the follower, at the baseplate, or in other positions within the magazine.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a side view of an example firearm illustrating a magazine equipped with a sensor module located at the follower and at the baseplate.

FIG. 2 is an exploded isometric view of an example sensor module positioned at the follower.

FIG. 3 is an exploded isometric view of an example sensor module positioned at the baseplate.

FIG. 4 is an isometric view of an alternate baseplate-mounted sensor configuration.

FIG. 5 is a schematic representation illustrating forces applied to a follower-mounted sensor.

FIG. 6 is a schematic representation illustrating forces applied to a baseplate-mounted sensor.

FIG. 7 is a schematic representation illustrating forces applied to an alternate baseplate sensor configuration incorporating a center-beam structure.

FIG. 8 is an electrical diagram of an example Wheatstone bridge circuit usable with the sensor module.

FIG. 9 is a schematic showing an example wireless communication interface between the sensor module and an external device.

FIG. 10 is a schematic showing an example wired communication interface between the sensor module and an external device.

FIG. 11 is a flowchart illustrating an example process for determining a round count.

FIG. 12 is a diagram illustrating example firearm operation with an active magazine and a passive magazine.

FIG. 13 is a diagram illustrating example configurations for detecting the presence of a round at the follower.

FIG. 14 is a flowchart illustrating an example process for identifying a type of ammunition-related event.

FIG. 15 is a diagram illustrating example devices that may receive information from the sensor module.

FIG. 16 is a diagram illustrating example formats for visually displaying a round count.

FIG. 17 is a diagram illustrating an example heads-up display mounted to a firearm optic.

FIG. 18 is an electrical block diagram of an example sensor module and associated electronics.

DESCRIPTION OF THE RELATED ART

Systems for determining the number of cartridges within a firearm magazine have been described using various sensing mechanisms. Magnetic-field-based approaches often employ a magnet in the follower and a sensor positioned along the magazine or firearm frame. Other approaches utilize resistive membranes or force-based sensing elements to estimate follower position or spring force. These techniques may be affected by environmental conditions, mechanical vibration, interference, or the need for multiple integrated sensors. There remains a general need for reliable, low-cost techniques capable of determining cartridge count under a wide range of operating conditions and ammunition types.