By Richard Comerford
One of the saddest statements about the Newtown Tragedy is that it was not the first time such a thing had happened. According to the Website stoptheshooting.org — created by Alex Algard in 2009 to commemorate the victims of the Columbine shooting — there have been 386 school shootings since 1992 and, in most cases, both the shooters and the victims have been under 19 years of age.
While it may be possible to ban future access to certain types of weapons and ammunition clips, there are already a huge number of multiround, rapid-fire weapons in homes across the nation. Indeed, in the immediate aftermath of the Connecticut slaughter, with the prospect of new government regulation in the offing, single-day sales of such guns hit a new peak. It’s likely that these legally owned armaments will be around for some time to come.
It is fitting for U.S. citizens to have a long and serious public dialogue about gun control, mental health services, violence and the media, and parental responsibilities and liabilities. But we cannot wait for the outcome of such discussions to protect the well-being of school children and teachers. We need to make sure that schools are safe havens for learning, where both adults and children know there is no threat of sudden, life-altering violence. From what I’ve seen, I believe that advances in magnetometer and other sensing technology make it possible today to set up unobtrusive ways to detect and pin-point the presence of weaponry near and within the grounds of our schools.
Take, for example, a device like the MC3316xMT magnetometer from MEMSIC, a 2012 Product of the Year recognized by Electronic Products for its small size, high accuracy, high sensing range, and low cost. By deploying a wireless network of such devices around schools, the sudden arrival of metallic objects of a size that might pose a threat could be detected. Sensor-location information could then be used to quickly train security cameras on the source, to determine whether there was any reason for further action. Creating such an early-warning system would give people a chance to prepare for any real threat — to go into lock-down and alert proper authorities — before any harm comes to anyone.
Perhaps this ad hoc design isn’t ideal for a school security system, but as engineers, we do have the ability to create practical systems to protect such institutions. It’s something we owe our country and our kids.
3 Comments
It is very naive to think that an early warning system can provide the protection from harm that Mr. Comerford states here. It diminishes the fact that this individual was evil. Evil will be done by evil people and many have done it without a gun. An example is to look at the Oklahoma City bombing that took 168 innocent lives including the 19 pre-school aged children. No gun, just a van loaded with high explosives. Banning a particular type of weapon or limiting magazine size, sensing a rifle or handgun, or any other measure being proposed fails to address the real issue, evil people will do evil things. The best we can strive for at the moment, is to provide a well trained, and armed staff. I don’t believe every teacher should carry a weapon by any means. I do believe that those who want the training and are willing to carry a concealed weapon can do more to protect the innocent lives in our schools.
Locking down the school would have done little to protect the children. The principal and teachers who tried to stop him did little to prevent it. I mourn the loss of the staff who did try. I mourn the loss of the innocent lives lost. Could a well trained, well armed staff stopped this evil? Maybe. The father of a child who attended the school appeared before congress. He stated he owned a firearm and would use it to protect his family. He said that he would use his firearm rather than call 911 because he could do something right then. He questioned why our schools don’t provide the same protection by arming its staff.
Sensors are great for measuring the attributes of a system, but a well constructed control system with its rule based algorithms, alarm logic, and protection schemes are required to utilize those measurements.
Maybe I’m upset that an article like this dismisses the evil behind the events and the evil within those individuals to propose that using sensors to detect a weapon will make our schools safe from those wanting to do evil.
I’m not a member of the NRA or do I provide support to any gun group. I do own several of the types of weapons under the proposed gun control Legislation. I am a strong believer in the right of a law biding individual to purchase and own any of the current types of firearms available
We need to focus on many issues surrounding the evil such as that done at Newtown. Those who have lost their moral compass, their lack of respect of human life, and disregard for what is right and wrong are to blame. But we are to blame, too. We make excuses or blame it on the environment in which they were brought up in. We fail to recognize and report those who are mentally disturbed. We fail.
When did it become a crime to properly discipline our children. When did we turn our responsibility as parents over to our teachers. I taught my children what was right and what was wrong. I taught them the consequences for not doing the right thing. I disciplined my children. I taught them to respect others. These were the same things taught to me when I was younger by my parents.
We cannot “engineer” the evil out of our society or the individuals with evil intent, but we can use the available means of protection to prevent or reduce the damage done by those doing the evil.
Magnetic sensing over wide areas (e.g. over an area of a school yard) is a difficult problem.
For example, here in upstate NY, the Earth’s field is about 0.5 Gauss total field, or about 0.2 Gauss horizontal component (the field values and vector direction (dip angle and variation) vary with geographic location). Most Earth’s field work is discussed in nano Tesla (0.5 G is 50,000 nT). The total field change typically changes on a diurnal cycle on the order of tens of nT in NY. So, that’s tens of gamma (a gamma is 10-5 Gauss). A steel automobile at about 33 feet causes a change in the total field of less than 20 nT (<20 gamma or <20×10-5 Gauss). So the few somewhat ferrous metal parts of most modern firearms would be nearly invisible only a few feet from a magnetic sensor and/or lost in the magnetic sensor noise floor.
The suggested sensors have a sensitivity on the order of 512 bits / Gauss with a 2 mG rms noise floor. As vector magnetic measurements, they are sensitive to both direction and magnitude changes, can probably “see” ferrous metallic incursions into an area of interest with somewhat more sensitivity than a scalar only measurement. Perhaps the aspect of 3D sensing can be further exploited to combine the three individual reading at each measurement and then further averaging the measurements.
However, another problem is that the readings will also be influenced by large ferrous masses at a distance (e.g. a school bus, garbage truck, etc.).
Probably, these are some of the reasons that metal detectors surround entrance walkway points for very localized sampling of a relatively close and small volume by RF techniques more like “metal detectors” as opposed to raw magnetometer instrument readings of a local point field in Gauss or nano Tesla. Also, such RF techniques are less dependent on ferrous metal content.
Similarly, driveway detectors (often fluxgate magnetometers using a second harmonic technique with high permeability cores) are located relatively close to where the vehicle is expected to show, such as near the side of a road or driveway.
The weapons detection concept presented is not without possible future application, such as if combined with complex digital signal processing based on measurements from many magnetometer points in a grid (probably many tens or hundreds of sensors). Such a grid would need to somehow detect offsets caused by large masses (e.g. vehicles) at a distance and factor them out both in terms of alarming, as well as to create a new reference level for local sensing. Also, magnetic sensitivity for alarming will be a strong function of the noise floor of the sensors in the grid. When relatively low cost magnetic sensors improve to have a low enough noise floor, changes in the geomagnetic field can also be measured and compensated for. Without a very complex implementation, and very sensitive sensing technologies with low enough RMS noise floors, this type of weapon remote sensing (concealed side arms and/or assault weapons) is probably an idea way ahead of its time.
Thanks for this thorough analysis, Joe. It does point out several of the difficulties in deploying such a system.
My thinking was to establish a perimeter of multiple (tens or hundreds) low-cost sensors with higher sensitivity that would create an alarm if crossed; I know that several companies are working on creating such sensors now. Proximity to the sensor would be relatively high when the perimeter is crossed, and not require as high a sensitivity as distance sensing, particularly taking 3D sensing into account. Tying the system in with other surveillance techniques such as RF and cameras would allow rapid detection of potential threats or recognition of benign, normal situations. Of course, sorting out the signature of a weapon from other allowable metal objects would require significant real-time computing power, but I believe the number of systems needed would create a large enough market to permit design of dedicated algorithmic-based hardware to handle data analysis and reduce false alarms.
I know that this requires some advanced effort, but as I said, I believe we owe it to our kids to try and make this happen.
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