1-Wire Network This web site, http://www.vcru.wisc.edu/1wire, provides monitoring of cold rooms and other facilities for the University of Wisconsin Horticulture Department. For more information contact Doug Senalik

Cold Rooms

Walnut St. Greenhouse

Carrot & Beet Lab

Refrig- erators

Ultra- colds

Equip- ment

Annex

Technical Details

Glycol System Failure Emergency Information

After hours, call the University Police Department non-emergency number 608-264-2677
and have them dispatch an emergency steamfitter
Horticulture building number is 0087
Horticulture customer number is B38925
Annex building number is 0128

Helpful hints

To have a shortcut to a specific cooler or two, add the cooler(s) desired to the url.
For example, for 404 only use:
http://vcru.wisc.edu/cgi-bin/1wire/fs6.cgi?show404=1
Or for 107, 109, and 111 only, use:
http://vcru.wisc.edu/cgi-bin/1wire/fs6.cgi?show107=1&show109=1&show111=1
 

Accuracy

The DS18B20 temperature sensor specifications claim an accuracy of +/- 0.5°C

On September 29, 2009, Checked calibration of sensors by placing in ice.
The following is an average of 25 measurements taken over 2 hours after the sensor was fully equilibrated
107 = +0.0600 C (high)
109 = +0.0504 C (high)
111 = +0.0600 C (high)
113 = +0.1256 C (high)
115 = +0.1176 C (high)
117 = -0.2356 C (low)
119 = +0.0576 C (high)
201 = +0.2596 C (high)
203 = -0.0696 C (low)
 

Cost of the system

• Wire - I am using the abandoned Cat 3 wire that is left over in the building after the 2008 network upgrade.
  Or new wire, if needed, could be purchased 1000 ft $56.00
• Connectors - 100 of these can be had for only $8.29: RJ-45 connector
• Temperature Sensors - The DS18B20 sensor costs $3.75 each in quantity of 10 Jameco 865936
• Humidity Sensor - A HT3-R1-A Humidity/Temp Sensor with case was $60.25, this is in the 404 seed storage room
• Computer Interface - A DS9097U-A which costs $28.00, is pluged into a serial port of one of our Linux servers, and acquires the data from the 1-wire network
  A cheaper option is to build your own from a resistor and four diodes for a couple of dollars
• Hub - I overloaded the adaptor trying to connect so many distant sensors, so needed a 6CH1-R3-A 6-port hub, which is located in the 216 wiring closet. The cost was $58.25 including a case (but I saved by using an existing surplus AC power adaptor)
• Software - I am using Digitemp and One-Wire File System, both of which are free software.
  Graphs are generated with Perl and gnuplot, also free
• Wireless connection to greenhouse - There is no ethernet network wiring in the Walnut Street Greenhouses beyond the main headhouse building, but a number of wireless access points are functional in this area. Using a published modification of a WRT54G router, a link from greenhouse 67 to the annex wireless network was made for about $50
  Since 2017 a Raspberry Pi is used to collect and transmit data over the UW-Net WiFi
• Example of source for 1-wire light sensor based on DS2406 chip
  Photo of this item mounted in a surface-mount ethernet jack
• Commercial system equivalent cost - Hard to know, here is one example for $495.00, only monitors one location though, or the Onset HOBO U30 with 10 sensor inputs is $714 (I don't think that includes the sensor cost)

Wiring Notes

The old jacks are wired to the RJ61 standard

Wiring for parasitic 1-wire sensors to a Raspberry Pi

from https://www.mkompf.com/weather/pionewiremini.html

Pinout for DS2482-800

Data Jacks used