Garden Endeavors

GREENHOUSE LOW TEMPERATURE ALARM

If you have a heated greenhouse and your heat fails on a cold night, you could lose a substantial number of your treasured plants. If you have a low temperature alarm system to notify you of such malfunction, you can have time to provide ancillary heat to save your plants. If you utilize all of the parts of the system described here, the cost will be just over $100, less if you don't need the Greenhouse Power Failure Module. An untimely freeze in your greenhouse can cost you far more than $100, so having such a system can be worth all the cost.

There are cheaper thermostats than the one I have listed, but you need to be certain to use a mercury switch type of thermostat, since operation in a greenhouse necessitates a thermostat that will perform in a moist environment, and contacts of mechanical thermostats may fail.

If you are heating with gas and no electricity is necessary for your greenhouse heat, the greenhouse power loss module can be left out.

Remember, even with gas heat, if your greenhouse heat relies on electrical service, the greenhouse power failure module is important because due to the possibility of GFI disconnects due to excess moisture, your greenhouse power could be cut off while your house power remains on.

The basic design includes a warning of general power failure, which can be helpful if you rely on electric alarm clocks.

PARTS LIST:

DESCRIPTION OF PARTS:

ALARM MODULE:

LED-1 RED http://www.radioshack.com/product/index.jsp?productId=2102849

LED-2 Green http://www.radioshack.com/product/index.jsp?productId=2062551

P-1 Piezo Transducer http://www.radioshack.com/product/index.jsp?productId=2062399

R-1, R-2 1 K Ohm resistors http://www.radioshack.com/product/index.jsp?productId=2994579

S-1 Mini Toggle switch http://www.radioshack.com/search/index.jsp?kwCatId=&kw=mini%20toggle%20switch&origkw=mini%20toggle%20switch&sr=1

S-2 Push Button http://www.radioshack.com/product/index.jsp?productId=2062543

Hobby Box http://www.radioshack.com/product/index.jsp?productId=2062281 http://www.radioshack.com/product/index.jsp?productId=2062543

B-1 9 volt Alkaline Battery

Battery Snap connectors http://www.radioshack.com/product/index.jsp?productId=2062219&numProdsPerPage=60&retainProdsInSession=1

T-2 12 volt DC power Supply http://www.tti-plus.com/12VDC-1000-mA-Plug-in-Power-Supply-2-1mm-Plug-p/tti-12vdc-1000.htm

C-1 Hookup wire - telephone cable. (You really only need two conductor wire for this application.)http://www.radioshack.com/product/index.jsp?productId=2049729

L-1 Relay http://www.radioshack.com/product/index.jsp?productId=2049722

S-2 Thermostat http://www.acehardwaresuperstore.com/honeywell-thermostat-for-1530-volt-systems-p-35427.html?ref=42

MONO Jack http://www.radioshack.com/product/index.jsp?productId=2103453

MONO Plug http://www.radioshack.com/product/index.jsp?productId=2103992

Optional Greenhouse Power Failure Module:

L-1 Relay http://www.radioshack.com/product/index.jsp?productId=2062481

Hobby Box for relay http://www.radioshack.com/product/index.jsp?productId=2062281 http://www.radioshack.com/product/index.jsp?productId=2062481 SPDT

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Last modified on December 31, 2008