As described in the attaching [url removed, login to view] project detail file.
(1.) create a low-cost, low-power projectile detection screen, shown in Figure 1a, and Figure 1e that can detect speed of pass-through objects accurately
(2.) Using line-laser, as shown in Figure 2a, as the Light source
(3.) Using multiple reverse-biased LEDs as the optical sensor
(4.) detection screens must be set in pairs, with the specification illustrated in Figure 1b, 1c and 1d
(4a.) able to detect pass-through projectiles with speed between 50 feet/sec and 5000 feet/sec base on using a 16Mhz microcontroller
(4b.) able to detect projectiles with size as small as 5mm in diameter
(4c.) must be powered by a 5V portable power supply, either a power bank or dry cells ([url removed, login to view] or 9V battery)
(5.)detection screen should be independent of surrounding lighting condition, whether it is placed indoor under fluorescent light, outdoor under direct sunlight, or in complete darkness
(6.)detection screen light source must be :
(6a.)line lasers as in Figure 2a
(7.)detection screen optical detection must be :
(7a.)reverse biased LEDs, OR
(8.) detection screen optical detection must be designed in modules (banks). If 24 reverse biased LEDs are required to cover the detection area, then it must be in a layout of 8 LEDs on 1 bank, the whole bottom will consists of 3 identical PCB modules. See Figure 1d.