Chamber Design¶
Written by Grace Lo
The chamber is a floating structure that houses the electronic components, with the ability to open and close to allow air flow. It has a few design requirements:
- Air Circulation: clearing out the internal air and cycling new air in
- Airtight and Constant Internal Volume during measurements
- Electronic Protection from water exposure
- Part Accessibility
- Ease of Maintenance: light and simple assembly
The chamber is constructed using parts that can be found in a hardware store or online. The structure of the chamber is built out of 1/2" PVC pipe for a simple assembly process and can be easily adjusted by changing the length of pipe. A standard pool noodle fits around the pipe and additional pool noodles can be attached to increase buoyancy. Our design takes the approach of an accordian-style AC duct glued to the top of the structure to open and close the chamber. This addresses the first two design requirements, since opening the chamber allows passive air circulation. Then the edges of the duct can be lowered to submerge under water for an airtight seal during the measurement process. An AC duct is rigid enough to maintain a constant volume when closed, but is also easily folded to open up the chamber. An acrylic support attached to the inside of the chamber guides this movement and holds the duct in place.
An acrylic sheet at the top of the chamber, attached using loop clamps, holds the electronic components. The height of the structure is chosen to ensure the electronic components are a safe distance from the water. The motor is mounted through the center of the sheet and the limit switch PCB is attached to its underside (left image), secured using machine screws and the threaded holes of the motor. The main PCB is also mounted on the underside of the acrylic sheet, with wire connections to the limit switch PCB. Since the portable battery is the largest and heaviest electronic component, it sits centered on top of the acrylic sheet (right image) to evenly distribute the weight. The current battery is made out of a conductive metal, so electrical tape was used to insulate the mounting screws as an extra layer of protection to isolate the electronics.
