Remote temperature monitoring
 

Does anyone know of an "affordable" device which will transmit greenhouse temperatures 100 metres to a display inside the home?

define "affordable"...

I will assume you have power in your greenhouse.

I personally use a server-room grade piece of kit called a Jakarta Interceptor; similar devices exist from other manufacturers. I then use a piece of open source software called Cacti to make graphs, although the interceptor makes it's own. This is described graphing here and gadjet here.

They are not exactly cheap, but being IP based is pretty awesome. You can also set it up to email you if the levels get out of whack (handy). Another option is to pair it with something like Nagios and an SMS gateway if you want SMS notification.

Another variation on that theme is to simply put a webcam in your greenhouse pointing at whatever sensors (thermometer, hygrometer) you happen to have in there.

Assuming you're not into digging a trench, a wireless router or two (or a simple bridge device from the likes of Mikrotik or Ubiquity) and you're set.

One day, when I'm a real grown up, my greenhouse will have network points. If I'm paranoid about lightning, the link back to the house will be fiber. As a bare minimum, I'd probably use an Ethernet Lightning Arrestor.

There are just wireless thermometers around, but I'm not sure how many have the range. Having it IP addressable however, is made of win and awesome.

The 100 meters is the primary problem. Most of the "long-range" broadcasting sensors get "iffy" about 10% shy of that.

I have a LaCrosse Technology Wireless 915 MHz Temperature Station (WS-9160U-IT) that claims a "330 feet" range. It retails for around $40 (the one I have left is $25, but I'm sure you can find one locally, and not pay the shipping cost.)

re: the 100m try to make sure you have line-of-sight with whatever you do use - i.e. stick it as close to the house as you can in the greenhouse, and on the closest window to the greenhouse in your house. If it works there, try a wall near that window. If not, go back to the window. Walls and radio waves are often not friends.

Once again, depends on the definition of cheap. I have the cheapest Sensaphone. About $400. Since it requires a dial tone to call you, you must have a wired phone attached. I was able to get around that by getting a $100 device called an XLink. It supplies the Sensaphone with a dial tone and links via Bluetooth to a cell phone. So a added a $9.95 per month free cell phone to my cell plan.

It calls both me and my wife up to 100 times until we acknowledge an alarm exceeding preset limits that we select. It ignores answers by your voice mail because you have punch in a code to prove you got the message in order to shut down the calls. I can also call the system myself at any time and get the temperatures at 4 points in the greenhouse.

It has worked perfectly for 3 years now. Total investment about $500 and $9.95 a month for the cell phone.

Thanks everyone.
Ray, I had looked at the La Crosse WS-9160U-IT, but although it has 330 feet it does require "line of sight" which is a problem for me. The video clip on their website states that the 330 feet is depleted by half EVERY time the signal goes through a wall or window. My greenhouses are away on the side of my house which has no windows. The house was built 1860 and the walls are thick solid, so are a real problem.
As for "affordable", that will depend on if I find something which I am convinced will do the job. I have located a device which the sensor costs GB£240 (I need two - one for each greenhouse) and the monitor costs GB£372. That is not affordable!

Richard

That's great for an alarm, but not a way to read the temperature remotely.

I did something similar using a Sensaphone in my house, so it can tap into the land line, and a remote temperature sensor (Thermalarm) connected to an RF sending unit (with a 300+ meter range).

well like I said I can call it anytime and get the temperature. I don't have to wait for an alarm. I also have a wired readout from a temperature monitor which was my first system, but I find the alarm to be most valuable becauseI don't want to sit up all every night reading a readout. Much simpler to go bed and have it call if necessary. Like I said, I can call it if I wish and get 4 temperature readings around the GH and listen to what's going on inside. Can.t say I've heard anything but fans and heaters but what the heck it's a free feature.

Missmolly,
That is really a cool idea. I've never wanted to take any chances with my exotic plants and orchids so they all live inside, crowding us quite a bit, during the winter. That seems like a sure way to avoid freezing or cooking them. Maybe an attached greenhouse will be an option, someday! Thankyou for sharing!

Got it. Sorry - I wasn't thinking of the unit being in the greenhouse, and forgot about the thermistor they provide.

Perhaps something like this with upgraded antennae (or even a wifi base-station in your attic near the GH if better antennas won't work) would work for you?
Wifi thermometer temperature email alert graph webcam | eBay

I have started thinking more laterally.
My internet service connects to my home by radio through an aerial on the roof (not by land line) . That little aerial is in line of sight from both greenhouses, so I am exploring the possibility of transmitting to that point then perhaps to softwear on my PC.
Not exactly what I intended, but better than nothing............but it all depends on whether there is a unit out there which can communicate with my internet aerial.

Richard

Hmmm, perhaps this is a little too simple, but I got a decent little temp gauge that reads the temp in my green house as well as the humidity and the temp in my home as well. Home Depot, it's from Accurite. cost me about $75, there were some that were in the 25 range that didn't give a humidity read out. I don't think I would feel "safe" with my orchids in the GH without it. I can even check and see what the highest and lowest temp was over the last 24 hours. totally affordable and super easy.

I'm guessing you mean one of the wireless systems with a sensor in the GH and a readout in your house that also shows the house conditions. Those are common and cheap but they have a very limited range. If your GH is connected or close to the house they work, but put it 100 ft or so away and you can't get a signal.

Once again I point out that remote reading systems are fine as long as you are looking at them. They are useless when you are asleep or otherwise not looking. That's why, in my case, I want something that notifies me that something is wrong. Thus my preference for an alarm like I have. As I mentioned before, my system is not limited to being an alarm. I can call it up anytime and get the current conditions.

Different things suit different situations. I lost my heat twice at night during very wintry conditions due to a malfunctioning relay in the controller. If I had not had an alarm, I would have lost all my plants. As it was I just had to sit up all night manually turning the furnace on and off. Could have been a disaster. Just became a PiTA.

Once upon a time.... I used a wired device. Sensor in the GH, display in my office, connected by 125' of buried wire. Inexpensive and reliable.

Until ice sliding of the greenhouse during an ice storm pierced the ground next to the foundation (where it stays thawed), severing the wire right where it left the GH, going into its buried channel.

Of course, all this happened coincident with a heater failure on a 7°F night, wiping out a 20 year collection of plants.

That is why control systems typically use 4-20 ma signals. If the signal drops below 4 ma then the system can recognize that there has been a signal failure and take appropriate actions such as issuing alarms.

You'll probably find your wireless internet is on a 5GHz link, and probably on a fairly directional antenna; I suspect unless you have access to the backend of that CPE, you're not going to win :(

I have been chasing this one for many months and must now admit defeat. There are systems out there but they are intended for commercial use and for an amateur the cost is telephone number size. Exploration with manufacturers cannot adapt the units nor reduce the price. I have lasted 15 years without such a facility, but I just thought that being retired and around the house most of the time I could just glance at something without tramping to my greenhouses. I know it is all proportional and with around 600 plants I need to be vigilant, but there comes a time when cost becomes overwhelming.
An interesting discussion topic though - thanks everyone.
Richard

DIY temperature monitor with failsafe alarm.
 

Here is a temperature sensor that provides a 4-20ma output ($125):
TTD25N-20-0100C-H Products

Here are panel display meters that accept 4-20ma input and have relay outputs for limit and loss of signal alarms ($280):
APM765 Panel Meter with Digital Display, Isolated 4-20mA and Modbus Output Options

Also a 4-20 ma with limit and loss of sensor alarm outputs but without display ($310):
260A limit alarm with DC current input and loop-power

Using 4-20ma signaling you can send the signal over a 2 conductor line for a thousand feet or more.

Check out Sero systems growpak 1... It a controller but you can use it to monitor your growing conditions... You can setup 4 modules. You can setup two RH/temps sensors and a net module two send live data to your computer or cellphone......


FYI: Herpkeeper is the same thing but cheaper.

Keith and David,
Many thanks, I had not seen these before. Measuring and transmitting does not seem to be my stumbling block, but my biggest difficulty is getting information from the sensors into my home 100 metres away and through thick solid walls. It is that which I have not yet been able to crack.
Both devices you have highlighted are most interesting. I shall enquire further.
Richard

Use a bridge router or two and run DD-wrp. I run it on a linksys N dual band and can get a signal on my iPad about 450 ft away(guessiment) to my mail box.

Care to explain that in layman's terms?

I tried to post a link from phone but not working... I'll post it tonight[
---------- Post added at 04:09 PM ---------- Previous post was at 02:35 PM ---------

Hope this will help....
You can have a wifi off your bridge router to your device(weather station in this case)
http://www.dd-wrt.com/wiki/images/9/...ter_Bridge.jpg

So if my "sensors" - whatever they may be - can connect to ethernet, I can simply have the wireless bridge connect to my home network?

Yes, and then whatever apps you want to monitor them. Cacti and Nagios are good open source toys for that sort of thing, particularly if the devices you're connecting speak SNMP.
This can be anything from as basic as webcam-looking-at-sensors that you have to keep an eye on to full monitoring, graphing and SMS/email alerts, depending on the toys you have to hand.

---------- Post added at 05:09 PM ---------- Previous post was at 05:08 PM ----------

p.s. note that having an 8P8C connector (RJ45) doens't necessarily mean plugging it into an Ethernet network will work - there are devices that use these connectors without the ability to "speak" ethernet, and even use Ethernet cable as wires.

---------- Post added at 05:12 PM ---------- Previous post was at 05:09 PM ----------

DD-WRT is an open source router software (firmware really) package that can turn compatible home routers into much more powerful devices. Some will even let you use USB/serial pins on the board of the router for Interesting Things.

---------- Post added at 05:16 PM ---------- Previous post was at 05:12 PM ----------

essentially, a wireless bridge can be thought of as a piece of ethernet cable running between your GH and House, carrying any ethernet traffic from your house to the GH and vice-versa. In some cases, running a routed (rather than bridged) network is better, but it depends on the application; bridged networks are more intuitive for most home users (because devices plugged into them behave as if you were plugging them into a switch/hub, and don't generally require as much configuration). If you go for a routed wireless link, you have to understand a bit about routing and how to get your devices to talk to each other before it will work; a fuller discussion of this is rather off topic, but I can go into it if anyone wants - with some concrete hypothetical devices, I can probably even suggest the configuration.

---------- Post added at 05:19 PM ---------- Previous post was at 05:16 PM ----------

Hypothetically (and assuming line-of-sight), using the right radios and antennae, you can have links over kilometers (handy if your greenhouse(s) are far away), whereas physical Ethernet (copper) wiring is limited to 100m; some kinds of fiber can go considerably further than 100m, and it provides isolation from lighting and other interesting potential difference effects which may manifest between your GH and house if you run wires (as of course does radio).

---------- Post added at 05:20 PM ---------- Previous post was at 05:19 PM ----------

Finally, if wireless networking interests you, the E-book available from Wireless Networking in the Developing World tells you more than you will ever need to know!

Yes or add a repeater depending on how far you have to go..... A bridge allows you to connect a ethernet device and turn that signal into wifi to transmit it to your home network wirelessly.

Just remember that the more you turn up the signal on your router the more heat is made by the router and it can over heat and kill your router..... I have removed the sides on my router.

I'm not particularly interested in modifications, as I don't have the time. Any recommendations for off-the-shelf components?

Bridge routers are an off the shelf idem.... There were companies that make long range routers also.... You just have to pony up!!!

Just to add most new router have the capabilities in the factory firmware to be repeaters. So, you don't need to use DD-WRT but it super easy to install.

Ray - Mikrotik and Ubiquity make numerous off-the-shelf goodies that are pretty sweet. I'm rather partial to the Mikrotik stuff (most of my work nework backbone and complex stuff is Mikrotik, with a few Ciscos here and there as managed switches).

Using grid antennae, you'll easily go a couple of hundred meters (kilometers in fact). Set up is pretty easy.

Have you Looked at Z-Wave?
 

Z-wave is a wireless system common in "home automation" set ups. The reason it might help you is that the individual units create a "mesh" network, so even if one unit is distant, another unit or two between it and the hub can repeat the signal, expanding the range. Maybe an outdoor light controller and/or an outdoor temp sensor between the house and greenhouse would do it.

I know there are z-wave thermostats, as well as temp and humidity sensors too. I'm not sure it would all be ideal for you, but it might be worth looking into

The other big benefit is that they can be accessed easily online, with an iPhone app, etc. and also tied into all sorts of automations, notifications, and nifty things . . .

Is Z-wave the same as Zigbee? It's quite short range compared to the sort of distances most greenhouse owners are looking to use it for. :)

I think zigbee is something else. This is from the zwave alliance website:

"The range of a Z-Wave signal is strongly influenced by the environment; for example the number of walls that the signal has to move through. Typical ranges achieved by Z-Wave customers are 30 meters (90 feet) indoor and over 100 meters (300 feet) outdoors in the open air."

Sounds to me like a line of sight from the greenhouse to the home's wall, with some other module to repeat/extend the signal into the house is at least possible. The main benefit is still that is is a mesh network, so limited range of one unit does not limit the total distance that can be covered . . .

This is a pretty good summary of the differences. :)
Info & Answers: What’s the Difference between Z-Wave and ZigBee, and Should You Care?, by Julie Jacobson - Electronic House

Good article.

My current alarm system (not a monitor) is a Thermalarm (bimetal thermometer in which the needle is one electrical contact, and adjustable limit pegs - too hot & too cold -are the others) connected to an RF sending unit, which is basically a garage-door opener key fob. It is AC operated, but has a battery backup.

I have a long-range receiver antenna (~400 meters) snaked out of the house on the wall outside of my office, and its circuit board is connected to a Sensaphone.

For monitoring, I am using a LaCrosse Technologies wireless temp & RH device that does have an alarm function, but unless I happen to be in the office, I'd never hear it.

I believe I am going to begin stocking a variety of the LaCrosse units for local and remote measuring, as they are realistically inexpensive, reliable, and will suit most folks' needs - as long as they don't have a stone wall to try to get a signal through!

Or even worse, the chicken-wire reinforced plaster that a lot of houses in SF are apparently built out of. Handy when your ancestors build faraday cages into your house...