As many of you know, I use an Arduino microcontroller
to monitor and automate much of my brew process. I'm planning a major upgrade to my home brewery, including a complete rework of the microcontroller code and functionality. The project is largely on hold right now (mostly due to the crappy housing market), but I've been tinkering with a few bits and pieces lately.
I want a means of electronically measuring the fluid level in my mash tun and boil kettle, but a mechanical float-type level sensor will just get in the way (or get broken). Sure, a float switch would work, but it won't necessarily measure the fluid level without some manual intervention. So, I started looking at other sensor types and brainstorming. Here's the result:
My mash tun and boil kettle are about 20 inches tall, so if I run a thin tube down the side (vertically), and cap it, the pressure inside that tube will be 0 - 20 inches of water (or roughly .75 psi, max). Using a simple calibration scheme and conversion factor, that pressure can be measured and translated to kettle volume. The Freescale MPXV5010DP
is a 0 - 10 kPa (0 - 1.45 psi) that operates on 5 VDC and generates a 0.2 - 4.7 VDC output signal that is proportional to pressure at a plastic port - perfect for measuring the pressure on a digital "sight glass."
Bench testing the 5010 sensor results in output that (with 10 bit ADC) is sensitive to within .1", which should be quite sufficient for the application. More to follow as I (very slowly) build the new system.
Turns out that my idea isn't exactly original. A bit of Googling turns up this paper by Freescale
, detailing the use of a very similar sensor as a level sensor.