Progress Report - Mechanical and Electrical Design (03/22/2012)

    Since my latest update, I have successfully completed both the voltage regulator board and the hydrophones interface PCB. The voltage regulator board contains three levels or stages. The board receives an input of about 32 V from the two lithium-ion batteries (in series), which gets stepped down to a regulated output of around 24.4 VDC. This voltage is supplied to each of the three L298 Dual H-Bridge motor drivers which operate the six thrusters. The output of this regulator (stage 1) also serves as the input to the stage 2 regulator, which reduces the 24.4 V down to about 19.1 V. The power cord for the Zotac board is soldered accordingly to pull this output voltage from the stage 2 regulator. This output voltage is similarly routed to the input of the stage 3 regulator which steps down the voltage to about 8.85 V in order to supply power to both of the Arduino boards. This voltage regulator board contains all the necessary input/output wires/cables as well so that it can directly connect to the kill switch Seacon connector, solenoid valve interface circuit, motor drivers, Arduino boards, Zotac PC, and also to the hydrophone interface PCB (the stage 3 voltage of about 8.85V can serve as the Vcc for the op-amps on the hydrophone interface PC-- 5V would be insufficient as the op-amps are not rail-to-rail input/output). The only negative of the board is that it features linear regulators instead of switching regulators for simplicity. However, I have derived a relatively simple, fast, effective way to conduct the dissipated heat from the voltage regulator chips to the aluminum platform, thus closing the circuit on a highly effective conductive network. This will effectively negate concerns of overheating and provide stable internal temperature during sustained operation.

I further designed and assembled the hydrophones interface PCB using DipTrace. The board came out nicely, and I spent several hours cleanly soldering all the op-amps, capacitors, resistors, wires, etc. to it. It too has all the necessary input/outputs connected to it, and is thus also directly ready for implementation/integration.

          -Eric Sloan (Mechanical Engineering Project Manager - 15th Annual AUVSI Robosub Competition)