air/gas pressure control

I need help designing a arduino based pressure controller with digital display. We currently use a manual pressure relief valve with an analog pressue gauge to control pressure in our bio reaction vessels, that generate their own pressure, so this only needs to serve as a vent basically. This is low pressure <50psi and I’d like to use an arduino based system I could set and monitor from a android tablet or PC via Wifi. Not quite sure what components to use for pressure sensing or regulation.

For a vent you will want a solenoid valve. You just need to be sure to get one that is rated to handle the maximum pressure or more. I’m guessing there won’t be much of a flow requirement. If so, the orifice size of the solenoid won’t be much of a concern.

As for the pressure sensor, I have only worked with lower pressure ones so I can’t recommend a specific model. To get good accuracy you will generally want to get one that measures a range close to what you need for your application so that will be a factor in your choice. You will also have a variety of options as to the communication protocol with the Arduino, you just need to make sure it’s supported by the Arduino, could be analog, SPI, I2C. Another thing to consider is how easy it will be to plumb into your system. I found that a lot of the cheap ones I looked at while shopping would have ended up being difficult to incorporate in my project.

I don’t know any specifics of your application but generally it’s not a good idea to rely on something like this to be 100% reliable. Bugs do happen, whether in a DIY project or a commercial product. If there’s any change that the device failing to vent the vessel could create a safety hazard due to over pressure then you should install a pressure relief valve that is set to a pressure above where the normal vent pressure is but below the maximum rating of your vessel.