I2C IO board project

[kladue]

Having tweaked the larger control application to death, I purchased a couple boards to start working up an I2C control system suitable for an all in one touch screen platform. For less than $50 I acquired an USB to I2C board, 16 Digital IO board and a 8 channel 12 bit analog input board to relieve my boredom. A bit of experimentation and a test application have sorted out power, 5V reference,communication and timing issues. Response is good with analog channel scan steps of 80 ms X 8 channels, and scan interleaving for digital commands. The goal is to use 0-5V sensors for temperature and pressure, and have enough digital outputs to operate the ball valve actuators. Found some 0-5V output analog sensors AD22100K with -50 to 150 C range that should be a good fit, still looking for low cost wet pressure sensors, ones that I have found are a bit spendy at $110 each but they are wet sensors with threads for pipe installation and a 5V output. Still have not picked up a PWM board, but one with 16 channels can be had for around $14, and coding is not hard to implement.
Here are a couple pictures https://picasaweb.google.com/kevin.ladue/I2CBoards

 

[jpalarchio]

What are the wet pressure sensors for?

 

[kladue]

HLT, mash tun, and boil kettle level sensors, cheap sensors are all dry sensors with a need for an air pump.

 

[jpalarchio]

I'm a Brewtroller user and a lot of testing has gone into pressure sensors on the forums over there. As you said, those are dry sensors and it seems the most reliable method ended up utilizing an air pump for the "bubbler method".

Any links to a wet sensor you're looking at? I'm curious about these and how they stand up to steam and heat.

 

[kladue]

Here is the Measurement specialties LM series pressure sensors http://www.meas-spec.com/downloads/LM.pdf, the 1 PSI model is just right. Mounted away and below the keg will keep the heat from the burner and hot liquid from bothering the sensor. I use 2 in the automated system and apply a scale and zeroing value to compensate for mounting elevation. While the Brewtroller is good at what it does, I was looking for more than that platform and BCS can deliver, but less than a full blown PLC system.