The primary goal of most of my research cannon experiments was to record the mechanisms of composite armor damage and/or penetration as it happened. This information is valuable in designing composite armor. Samples were fitted with measurement guages, shot and the effects recorded. But these events are brief, normally lasting less than a thousandth of a second on small samples. Some of the most valuable information lasted less than 18/100,000 of a second. In order to maximize the learning that can be gained, the electrical measurement ciruit has to respond almost instantly.
I designed and built all of my own circuits using common parts from electronics stores. Usually, I was measuring the time span between two signals. In order to do this I designed my circuits to yield four possible voltages (V), for example: 0 V, 2 V, 4 V, or 6V. If neither switch worked, the circuit continued to indicate 0V. When the first switch was closed, the circuit went from 0V to 4V. When the second switch was closed, the circuit yielded an additional 2V. If both switches worked properly, the circuit would jump from 0V to 4V when the first switch was closed and then from 4V to 6V when the second switch was closed. In this manner, I knew if both switches had worked properly and the time between their closings.
The first switch was of my own design and construction. I fabricated it and mounted it on the front face of the armor. It was physically closed by the projectiles impact. The first switch also served to initiate the oscilloscope's data recording.
The second switch was not truly a switch, but a custom built, piezoresistive, z-axis carbon strain gauge. These were manufactured to my specifications by the company that invented them. When the damage wave reached it, the gauge changed resistance and a voltage was created in the circuit.
Batteries were used as the electrical power source, but they were not alone. Batteries depend upon the speed of their chemical reactions to begin supplying electrical current. Unfortunately, batteries are way too slow to work by themselves. The answer was to include capacitors in the circuit.
My circuit was able to provide electrical power at the correct level within 6.7/10,000,000 of a second after the projectile impacted the armor. During a period in which over 300 shots were fired from the research cannon, only one target failed to provide data and that was due to lab visitor playing with an alignment bolt.
The real secret to research success is to check your circuits and switches over and over. I checked my ciruit and switches at least six times before every shot. There is no magic, just tedious, painstaking effort. What I did with my circuit and switches is no different than the ammo reloading efforts put forth by a skilled, long range rifle competitor.
I designed and built all of my own circuits using common parts from electronics stores. Usually, I was measuring the time span between two signals. In order to do this I designed my circuits to yield four possible voltages (V), for example: 0 V, 2 V, 4 V, or 6V. If neither switch worked, the circuit continued to indicate 0V. When the first switch was closed, the circuit went from 0V to 4V. When the second switch was closed, the circuit yielded an additional 2V. If both switches worked properly, the circuit would jump from 0V to 4V when the first switch was closed and then from 4V to 6V when the second switch was closed. In this manner, I knew if both switches had worked properly and the time between their closings.
The first switch was of my own design and construction. I fabricated it and mounted it on the front face of the armor. It was physically closed by the projectiles impact. The first switch also served to initiate the oscilloscope's data recording.
The second switch was not truly a switch, but a custom built, piezoresistive, z-axis carbon strain gauge. These were manufactured to my specifications by the company that invented them. When the damage wave reached it, the gauge changed resistance and a voltage was created in the circuit.
Batteries were used as the electrical power source, but they were not alone. Batteries depend upon the speed of their chemical reactions to begin supplying electrical current. Unfortunately, batteries are way too slow to work by themselves. The answer was to include capacitors in the circuit.
My circuit was able to provide electrical power at the correct level within 6.7/10,000,000 of a second after the projectile impacted the armor. During a period in which over 300 shots were fired from the research cannon, only one target failed to provide data and that was due to lab visitor playing with an alignment bolt.
The real secret to research success is to check your circuits and switches over and over. I checked my ciruit and switches at least six times before every shot. There is no magic, just tedious, painstaking effort. What I did with my circuit and switches is no different than the ammo reloading efforts put forth by a skilled, long range rifle competitor.
