APA-1 PERFORMANCE

OVERVIEW / DESIGN / CONSTRUCTION / PERFORMANCE

The performance of the APA-I will be determined through a buildup of measurements as systems are constructed, problems arise, and problems are overcome. As testing is carried out the results will be briefly discussed here.

Optical Interrupt:

The optical interrupt circuits provide feedback to the micro-controller as to the location of the projectile during the firing sequence. There are a total of two sensors at the front of the first and second stage accelerator coils. In order to easily confirm the detection system is working an inverted output if fed to an orange led mounted on each PCB. This LED is turned on when an object enters the area around the QRD1114. Below is images of the first stage sensor in ‘no-projectile’ and ‘projectile detected’ states. As you can see the orange LED glows in the presence of the small screwdriver.

OPTICAL INTERRUPT TEST 2015

Low Voltage Management:

The low voltage management PCB is fixed to the top inside of the coilgun at the front. It is a fairly small board but houses a 5V 3.5A buck converter, ~16V 500mA SEPIC converter, and the system micro controller. This small board powers the entire coilgun (excluding the high voltage capacitors) so reliability is a must. After several months the board still operates and power all the circuits silently and without much heat dissipation. Test will continue as the high voltage management board and capacitor discharge boards are tested. Below is images of the voltages for the battery, 16V, and 5V lines.