T&L Publications

I'm looking to create a temperature reader for several locations, up to 12 locations in my little kit. This is for Apartment buildings, I want to be able to install a sensor next to the thermostat and be able to read the temperature remotely in the utility room. As you probably already know, some people complain that its too cold in the winter, etc so I would like to be able to get instant readings of their apartment. Maybe even get a logger like every 15min or 60 min working to help determine issues.

So, can anyone suggest parts to use or what I will need? I'm basic with programing, i know a little of VB if needed, scripting, PHP, HTML, I'm not a pro at it. I also tried working with the Arduino a little and i think I can handle that and I tried another system that I got working but it worked with a 4 wire temperature reader.

I'm looking for something that would work on 1 wire or max 2 wires if possible, plus I'm trying to keep the thermometer as small as possible near the thermostat so its not an eye sore. Any suggestions would be great, links, pictures, plans, anything.

Thanks so much,

-Pete

Take a peek at these:

http://para.maxim-ic.com/en/search.mvp? ... ree=master

The 1820 series are used widely with hobbyists so there are alot of sample projects out there on the net.

You need 2 wires going to each sensor (1 data/power wire and a ground wire). Look at the parasitic ones - they are the ones that steal power from the data line. The worst case with these is 3 wires (non-parasitic). But, remember, with parasitic power, the temperature conversion takes a bit longer, IIRC. If it were me, I would use the 3 wire configuration with Vcc & ground & data (18B20). But, if you already have two wires available in the location, use a part that ends in "-PAR".

Hope it helps,
Kevin

Hi Kevin,


Are any of those wireless?

I was looking into building a wireless too at one time, and still kick around the idea a bit. I needed a good refridge monitor and i wanted the sensor inside and the display outside. I ended up using a non wireless solution where the uC measured the temperature via a thermistor inside the refridge wired with two #32 gauge magnet wire leads. The leads only had to be about three feet long because the display would be right on the outside of the fridge.
I kept with non wireless because i got much lower current consumption which allows the batteries to last for something like two years before they have to be replaced. Transmitting and receiving would mean more battery replacements and of course two circuits instead of one.

Still a bit interested in this myself too though for another application where the current consumption isnt as much of an issue,
and i need about 50 yards of reliable transmit distance.


For anyone interested, there is also the power line transmitter method, but that's a little involved too.

I recall that there is remote instrumentation available for connection from sensors to computer network lines, just like connecting a remote printer. Unfortunately, that's all I recall.

They are not wireless out of the box. They are in a TO-92 package, IIRC.

There are a bunch of wireless modules of various types out there though. Microchip has some, sparkfun has some and I am sure a slew of other places. They seem expensive to me for just tinkering but if I had a specific project where I needed wireless, I would look into them more.

Here is a cheap one from sparkfun:
http://www.sparkfun.com/commerce/produc ... ts_id=9582

And you can check out the wireless stuff microchip has (seems more expensive):
http://www.microchip.com/wireless

And, no. I have not seen anything other than modules. This is due to FCC certification. I am sure you could make one yourself but the FCC regs may prove more trouble than it's worth.

Kevin

For just an IC, I stumbled across this:

http://focus.ti.com/docs/prod/folders/print/cc1101.html

It looks interesting and I would love to check it out but tomorrow is my 1st day of college (at 40+ years old) so I think I will be busy for a while....

Kevin

Have you considered X10?
http://www.resconsys.com/products/stats/x10.htm

Nielubie wrote: I'm looking for something that would work on 1 wire or max 2 wires if possible

You might want to look at http://www.midondesign.com/TEMP08/TEMP08.html

Mitch

hi,

this you can buy. I have a system in my home, 1 central controller, and a thermostat and one or more heater actuator(s) per room. works great!

http://translate.google.nl/translate?js ... l=de&tl=en
just my two cents...

fripster

Are you still interested in this? I built a Bluetooth wireless temperature monitoring system that reads a single sensor and reports data to a PC. I don't know if I will have the time to make it a commercial product (the person who wanted it went out of business!!), but I have a few PC boards made up if you want to buy one of the prototypes from me. No idea what would be reasonable, but contact me and we can talk.

MrAl wrote:Hi Kevin,

Are any of those wireless?

I was looking into building a wireless too at one time, and still kick around the idea a bit. I needed a good refridge monitor and i wanted the sensor inside and the display outside. I ended up using a non wireless solution where the uC measured the temperature via a thermistor inside the refridge wired with two #32 gauge magnet wire leads. The leads only had to be about three feet long because the display would be right on the outside of the fridge.
I kept with non wireless because i got much lower current consumption which allows the batteries to last for something like two years before they have to be replaced. Transmitting and receiving would mean more battery replacements and of course two circuits instead of one.

Still a bit interested in this myself too though for another application where the current consumption isnt as much of an issue,
and i need about 50 yards of reliable transmit distance.


For anyone interested, there is also the power line transmitter method, but that's a little involved too.