Overinflated to bursting or underinflated to mushiness, inflatable boats are notorious for having either too much pressure from the heat of the sun which can stretch or burst the material, or not enough pressure as they get cooled by cold water and lower nighttime temperatures which makes the boat soft and flimsy.
I figured out I can manage my boat’s pressure with the Programmable Air project. It contains all the hardware needed for managing air pressure in the tubes of the boat. Although it is not powerful enough to pump up the boat from a fully deflated condition, it can easily compensate for the slow change of pressure over time due to the changing temperatures throughout the day.
A larger inflatable boat using an outboard motor with an electric starter typically already has a 12 volt battery that can be used to power the Air. In boats without on-board electrics, a portable battery can easily be added. A 10 to 20 watt solar panel is recommended to maintain the battery in any case. After all, the sun is creating the need to manage changing air pressure, so why not use it to power the system?
For a complete system, add a splash-proof box with a connection for power (solar or onboard) and a hose with an inflation cap compatible with your boat. In my case, the enclosed steering pedestal provides the splash protection and, since I use an electric-start outboard motor, the 12 volt power needed by the Programmable Air is already on the boat.
The Arduino Nano can easily run the code needed to sample the pressure sensor and cycle the valves and pumps. Inflate your boat to the desired pressure then, when first turned on, the Programmable Air samples and subsequently maintains the pressure. The red button is used to raise the pressure, the blue button to lower the pressure. The NeoPixel actively indicates high or low air pressure before the Programmable Air takes action. The NeoPixels will begin to glow blue as the pressure drops and glow purple as it rises, just before the Programmable Air takes action to correct the pressure.
Programmable Air contains two air pumps so, since the project is operating solely with positive pressure, the vacuum pump could be used as a second pressure pump in parallel to the first pump by using the supplied tee and a simple code change.