Control Box (part 2) The Circuit

bread board circuit

Control Box Circuit

The circuit for the ROV control box is relatively simple and straight forward. I constructed this circuit with two boards. The "main" board sits inside the bottom housing of the control box and a smaller board is attached to the underside of the top panel of the control box. The two boards are connected with a ribbon cable that can be detached and allows for easier dissasembly. Additional features include an external RJ45 jack for communicating with the ROV via RS232 as well as an external RJ11 jack for updating the firmware of the MCU via In Circuit Serial Programming (ICSP). I started out with a simple breadboard circuit and added features/components one at a time as I got them to work correctly. I then proceeded to solder the circuit together using perf-board. Once I felt reasonably confident that my design was going to work, I drew up the schematic and PCB using KICAD. The actual construction at this moment is shown below :

Exterior view of control Box:

Exterior side view of control box

Top down view of control Box:

Top down view of control box

Interior view of control Box (Perf-board, no LCD connection)

main circuit board of control box

Interior view of control Box:

(Shown with PCB made from my design by Oshpark. with some additional features added)

interior view of control box

Unpopulated Main Board PCB

main circuit board schematic

Populated Main Board PCB

main circuit board schematic

Main circuit board schematic:

main circuit board schematic

Main Board Hi-Res Schematic

Unpopulated Top-Cover Board PCB

main circuit board schematic

Populated Top-Cover Board PCB (with LCD Connections)

main circuit board schematic

Top panel circuit board schematic:

top cover circuit board schematic

Top Panel circuit board Hi-Res Schematic

The schematics may come in useful once we get to the code writing section as it can help you visualize what is going on as we configure pins and transmit signals based on various inputs. As far as the RS232 transceiver (made by Maxim Intergrated), it is relatively simple to hook up and the documentation regarding capacitor values and pin connections can be found in the data sheet here. The 20x4 LCD displays sensor information as well as any alerts (Leak detected, ESC initialization info etc...) Future additions that are not yet included in this tutorial include a video camera interface and a robotic gripper arm.

Next up, Control Box (part 3)