Sentri Camera

Safety Dynamics specializes in the use of smart sensors for threat recognition and localization. Safety Dynamics is currently installing and supporting a system for law enforcement called SENTRI (Sensor Enabled Neural Threat Recognition and Identification).

The system is a breakthrough Technology that recognizes gunshots and explosions and sends range and bearing details to cameras which can then locate the source of the event.

Enabling of acoustic recognition takes place in a three phase process:

1.The targeted sound, such as a gunshot, is recorded and "trained" on the super-computer that isolates the sound signature amidst background noise.

2. The output parameter is uploaded onto the execution platform.

3. The run time parameters are adjusted and managed by the customer to adapt to requirements for distance, discrimination, and false positives.

So What Makes Us Different?


Local processor in box = speed of gunshot detection. There are other gunshot detection systems that are commercially available but none offer the same functionality as the SENTRI System. The system resides on a small computer board (about 8 inches by 6 inches) with four small microphone inputs. These components are mounted in a weather resistant box and typically connected to a camera and Ethernet network. Because all the processing that is necessary occurs on the processor board, the determination of a gunshot occurs in about 4/10ths of a second. Others systems rely on collecting the data from installed microphones (typically in a grid formation) and shipping that raw data to a central processing station along a network. These types of products claim that they can confirm a gunshot in 5-12 seconds (some take even longer). A simple example shows the impact of time during a gunshot event: assuming that a gunshot is fired from a person walking (the average walking speed is about three miles per hours, or 4.4 feet per second) a delay of twelve seconds would put the shooter 52.8 feet away from point where they discharged the weapon. Now assume that the shooter runs after discharging a weapon (average running speed would be 7.5 miles per hour, 11 feet per second) a delay of twelve seconds would put them 132 feet away from the discharge point. Because SENTRI has an on board processor, in these scenarios, the shooter would move 2.2 feet or 5.5 feet depending on whether they were walking or running.


Knowing exactly where to move a camera once there is a positive identification of a gunshot is paramount for law enforcement to identify the perpetrator. The SENTRI system has been tested to show that it can precisely show where the gunshot occurred within 1. Assuming the distance from the SENTRI gunshot sensor is 600 feet, a one degree differential would mean that the SENTRI could be off by a maximum 20.94 feet. Other systems claim to be accurate within 25 meters. Converting this to feet (3.3 feet per meter) they could be off by as much as 82.5 feet. One other major advantage to the SENTRI system is that we not only calculate the azimuth of the event (1-360) but SENTRI also calculates the elevation of the event as well. This translates to not only knowing what building the shooter discharged from, but the SENTRI will report what window ledge was used to shoot from.


Because each SENTRI unit can be fully functional on its own, units may be installed and moved at any time. For some applications (special sporting events, holiday celebrations, elections) it may be desirable to place a SENTRI system in service during the duration of these events. SENTRI is easily mounted on portable tri-pods that allow them to be placed anywhere 110v A/C power and a network connection (wired or wireless) is available. This allows the user to use the SENTRI whenever and wherever is necessary. Placement on rooftops or on the ground makes coverage extremely flexible.


One of the major objectives when designing the SENTRI solution was to utilize industry standards whenever possible. This means that the user does not need to replace existing infrastructure in order to integrate SENTRI Technology. Data is transported via common Ethernet communication and can be configured to utilize wired or wireless protocols and encryption algorithms. The user software is Windows based and is capable of running under Windows XP or Windows Vista. SENTRI can use a multitude of off-the-shelf analog cameras to slew to an event. SENTRI will work with just about any camera brand and we are in the process of integrating our system with cameras that can monitor in 360 at all times. This includes the use of video analytics to further help with the identification of people involved in gunshot events. Data output is sent via RS/232 or TCP/IP to whatever network connected device you wish. SENTRI has electronic relays that will allow the user to control gates, lights, or other devices when an event is detected. Remote upgrades and monitoring is also possible. Everything happens in one box!!

Blast Proof and Fire Solutions are official distributors for Safety Dynamics.