Vacuum monitoring system
Hi Folks,
Figured I'd tell people a little about a "fun" project we did here at the UVM PMRC this past season. There is a requirement for students in the UVM Engineering College to do a senior team project of some sort. They are presented several different topics and get to choose the one they want to work on. We proposed last fall that a team build a "wireless maple vacuum monitoring system". We worked with a group of 3 students who consulted with us extensively about what we wanted, and then went back and forth with them several times in regards to what we (thought) we wanted and how to do it.
The end result of this was that they built us 11 sensors (Picture 1) to put in various sections of the mainline system throughout one part of our woods. Each sensor contained a microprocessor and 900 mHz communications, batteries, and a temperature and pressure sensor. In addition there was a base sensor. In use, the base sensor was down at the sugarhouse near the pump, and the vacuum level of the other sensors was compared to the base sensor. We could adjust the vacuum differential to monitor how far each individual vacuum sensor in the woods was from the base sensor. A hard-wired display board allowed us to see at a glance whether each sensor in the woods were within our setpoint of the base sensor (green LED, Picture 3), were below the base sensor (red LED, indicating a leak), or had lost communications (blue LED). Upon a leak occurring, an alarm could sound (can also be silenced). A measurement of each sensor was made every 2 minutes throughout the season, and all the data were logged on an SD card.
Attachment 5771 Attachment 5772 Attachment 5773
The base sensor communicated to a computer via a small interface running at 2.4 GHz, where we could observe all the pressures and temperatures for each sensor, and also see graphically what the last 10 readings for each sensor had been. If there was a leak (based upon a setpoint vacuum level), a warning box would pop up on the computer screen. Optionally the system could also send out an email or a text message to alert the operator of a leak or other problem.
The goal was to build a system that would let the sugarbush manager know almost immediately if there was a leak and to pinpoint the probable location of the leak within 100 yards or better. In this way, we could reduce the need to have employees constantly patrol the woods for leaks, but rather detect and fix problems (leaks) very quickly if they occurred, because leaks reduce vacuum, which reduces sap yield.
We had a lot of fun playing around with the system, introducing leaks in places (after the season was over) and plan to do a lot more work developing this system. It was very interesting to watch each of the lines as things froze up and then again as they thawed out. This system will definitely help us understand the limitations and advantages of different types of tubing sytems, and help to optimize designs (future research).
So....one of the reasons to post this is to see what kinds of things sugarmakers MIGHT like to see in such a system. We already know we need to work on the range (probably using dedicated repeaters to extend the distance), and are also considering having a ranging system for use in the woods (two purposes....to check signal to the base station to aid in positioning sensors, and secondarily for use by people in the woods fixing leaks....this way they'd get immediate feedback via the roving unit whether their repair was successful).
Similar systems could also be made to measure vacuum level and tank level in remote areas (but these would require either cell phone or internet access at the monitored site).
So....what else would you like?
Finally....no, you can't buy this system. The students may at some point be interested in producing something that would be commercially available, but we aren't at that point quite yet.
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Originally Posted by jason grossman
