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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

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    • CommentAuthorowlman
    • CommentTimeNov 23rd 2011 edited
     
    Now that my new CH and DHW supplies are all complete I would like to monitor various temperatures from one place in the home without going into the plant room and looking at several dials, just convenience I guess. Getting the probes to insert under insulation etc., doesn't seem to be too much of a problem. The difficulty is getting a simple, cheap, monitor device that I can either scroll through or display up to 5 or 6 temperatures simultaneously, preferably mains powered. There are plenty of industrial gizmos available at £300 plus but many of them have other command functions that I'm not interested in. it's just simple monitoring I need, also I don't want a computerised system. Any ideas??
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 23rd 2011
     
    Several internal/external monitors, they are cheap but the external wire is not always long enough.
    Does seem cheaper to use an old PC, but energy hungry. If you find one let us know.
    •  
      CommentAuthorJSHarris
    • CommentTimeNov 23rd 2011 edited
     
    It'd be dead easy to build, but it seems difficult to find a ready to go unit.

    The little four channel data logger I built last week (the Mk 2 in a continuing series of datalogger developments......) displays the temperature from four sensors whilst it's logging data to memory for download to a PC. It would be really simple to build one that just displayed temperature from multiple sensors, all that might be needed might be a bigger display or a scroll capability (easy to do). It looks like this with no sensors plugged in (excuse the rubbish photo, I just took it to show what it looks like):
    • CommentAuthorowlman
    • CommentTimeNov 23rd 2011
     
    Thanks ST thanks JSH. It seems I'm not the only one to have hit a brick wall with such a requirement. One company I contacted wanted £650 for a 6 channel monitor/display and then another £ 21 each for the probes.
    I was thinking more like £40-50 for the monitor and £10 for the probes. As you say JSH a digital readout device or two and a bit of home help may have to suffice. :sad:
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 23rd 2011
     
    Posted By: JSHarrisIt'd be dead easy to build, but it seems difficult to find a ready to go unit.


    Could I manage it?
    • CommentAuthorowlman
    • CommentTimeNov 23rd 2011
     
    I did find one company who are currently working on producing such a device but not ready until next Spring. If I'm prepared to wait they say they will alter one to do readout only, as the one under development also has command functionn.
    •  
      CommentAuthorJSHarris
    • CommentTimeNov 23rd 2011 edited
     
    I've just roughly costed up the bits. The ucontroller is around £2.50, the display is around £20 or thereabouts (depends whether you can make do with 16 characters x 2 lines, or need maybe 20 characters x 4 lines) and the sundry components are maybe another £2 or £3 . If you want the sensors to plug in, then budget on around an extra £3 per sensor for connectors (my Mk 1 has the sensors hardwired). The power supply can be any low voltage adapter you may have lying around (mine's running on an old Netgear router wall wart). If you want it in a box than add another £5 or so for a plastic one from Maplin. The temp sensors are DS18B20 pre-calibrated three pin jobbies, that cost around £1 each if bought in quantities of 10 or more via eBay, or maybe £2.50 to £3.00 each if bought one-off from UK suppliers. Sensor cables can be just cheap telephone cable if they are going to be permanently wired up, or use thin three core flex if you want to make them OK for portable use. The sensors can easily be protected by some heatshrink sleeve, this will seal them well enough to cope with immersion if an adhesive lined sleeve is used. There may be another £4 or £5 worth of odds and ends.

    Construction needs a bit of soldering, nothing too onerous. The main snag is that the ucontroller needs programming. No big deal, but it does need a special cable that costs around £12, plus a connector at around £1.50. I could probably programme up the odd chip or two for people, and might be able to put together some kits of electronic parts, but I probably don't have the time to make more than a few.
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 23rd 2011
     
    I am willing to give it a go and can follow instructions, be a giggle.
    Be nice to have the largest display practicable if that does not make soldering any harder.
    Got a few hours spare at moment too.
    •  
      CommentAuthorJSHarris
    • CommentTimeNov 23rd 2011 edited
     
    A 20 x 4 display is around £24, compared with the 16 x 2 display at about £12. Each temp display needs 7 characters if it's in the format "T1=+18*" where * is a space between readings. 20 x 4 would allow a display that showed three sensor readings per row (no need for a space on the final sensor display), or 12 sensors readings in total, although the ucontroller I have in mind would only read 7 sensors I think. It should be possible to have slightly more verbose displays with a bit of tweaking. Each temperature displayed needs three characters, a sign plus two digits.

    The display doesn't need much soldering, just a handful of components on 0.1" pitch. The same goes for the rest of the components. Some thought needs to be given to the way the sensor leads are arranged. My Mk1 datalogger (just three channels, no display, the one that produced the last dataset on the other thread, see photo below) has the sensor leads permanently fitted, which is a pain when you have one of the sensors going through the wall to measure the OAT.
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 23rd 2011
     
    Was thinking of putting the sensors on plugs and sockets (Possible RJ11 or the smaller one, is that 4P4C) as they can go through a small hole and are standard off the shelve parts. Easy to make extensions too.

    Do they need a board to be built onto? Had to make something at college with a bread board (think it was a multi-vibrator), that was easy enough (once I got new reading glasses).

    Case does not worry me as I will probably put it in an IP one with a window on the front, but that can come later.

    So any chance of a parts list and suitable suppliers?
    •  
      CommentAuthorJSHarris
    • CommentTimeNov 23rd 2011
     
    Sure, I can probably sort out a full list over the next day or so, with suppliers etc, or could maybe sort out a group buy type thing and maybe put together some PCBs to make it easier to build. It could be built on a bit of breadboard, but it's not hard to make a PCB (I use a laser printer, some photo paper, a domestic iron, a bit of copper covered board and some etchant - takes around 30 or 40 minutes per board).

    I've used standard 3.5mm stereo jack plugs and sockets for the sensors. These are cheap and easy to hook up to thin cables and the sockets can be simply fitted into drilled holes in a case. The sensor on the end of the cable is only about 7 or 8mm in diameter with the heat shrink over it (could maybe be made a mm smaller with something like a blob of araldite over the wires instead of the heats hrink). The 3.5mm plugs are around 9 or 10mm diameter.

    Making a datalogger is a fair bit more work than just a simple multi sensor temperature display, as it needs a real time clock, some memory to store the data and a means of setting it up (setting date, time, sample rate etc). I'm working on making one that is stand alone, that doesn't need to be hooked up to a PC to be programmed and dump data. I was trying to get a USB interface working, but have found a cheap way of talking to a uSD card, so am working on using that instead. The idea is that the settings will just be a text file, loaded on to the uSD card via a PC and card reader (or any other device that will write a text file to one of these cards). The stored data will be on another text file on the card, in comma separated value format that can be read straight in to a spreadsheet.
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 24th 2011
     
    Sounds the business, it is about time I got myself a present, last year it was the CC stuff. Shall leave it with you.
    • CommentAuthorowlman
    • CommentTimeNov 24th 2011
     
    Can you count me in too please JSH. I have to admit to never doing any electronic stuff before, just some domestic wiring, so all the talk of breadboards, etchant, RJ11, plugs etc., is all a bit double Dutch. I'm a cabinet maker by trade so it will probably all end up in very smart Masur Birch housing, or something like.
    I dont know if my needs are the same os STs, but ideally, I'm after about 6 sensors, ( I could come down to 4 if that makes a difference). The sensors are all to be inserted into either cylinder pockets or inserted under insulation, so no water contact, I may consider an outside sensor though. Ideally, they all need to be wired into a nearby wiring centre, and from there on to the house utility cupboard kitchen via a single multicore cable.

    Mike
    •  
      CommentAuthorJSHarris
    • CommentTimeNov 24th 2011 edited
     
    OK, I'll take a look at what's needed to make a couple and see what I can do.

    ST, do you want to be able to log to uSD card, or just a temp display like owlman?

    The current spec for the uSD card logger gives 5 temperature channels plus one channel that will monitor a switch opening or closing. It should be able to drive a simple display that will show the last measured value on each channel, the number of samples read and the current time.

    The plain temperature display could do 7 temperature channels with a verbose display and a scroll button. I reckon a two line, sixteen character display would be OK, as each line could be a sensor with two sensors being displayed at any time and the scroll button being used to roll around each sensor in turn ( I think!). It could easily be made battery powered, with a switch to turn it on and off, as it wouldn't have an appreciable warm up time. If used for around 10 minutes total on time per day, an alkaline PP3 would last around 250 days. If only used for 5 minutes total a day then the battery would last twice as long.

    The display could look something like this:

    SENSOR 1 = -15 C
    SENSOR 2 = +19 C

    with the ability to scroll around a loop, so that the roll over looks like this:

    SENSOR 7 = + 8 C
    SENSOR 1 = -15 C
    • CommentAuthorgarypcook
    • CommentTimeNov 24th 2011
     
    I'd be interested as well - simple display for 3 or 4 sensors would be okay, although a data logger also sounds of interest. Sensors would be inserted in pockets, with minimum of 1.5m long leads.
    Gary
    •  
      CommentAuthorSteamyTea
    • CommentTimeNov 24th 2011
     
    I would like to be able to log to an SD card ore than see an instantaneous display, but having that would be good too, so both please.
    7 channels will be good, The CC does 10, 9 from external sensors and 1 internal, and that has done me well as I only use 4 at the moment, but have plans for others (like external temp).
    • CommentAuthorpmusgrove
    • CommentTimeJan 13th 2012
     
    Did anything come of these plans. I am now looking to link 5 sensors together and would be very interested to know where this project went.
    •  
      CommentAuthorJSHarris
    • CommentTimeJan 13th 2012
     
    I have a working prototype that logs DS18B20 "one wire" temperature sensor data (using the full capability of the sensor) and sample date and time to a microSD card. The code seems reasonably robust now, but I haven't added the display yet. Set up is by writing two very short text files to the microSD card on a PC with a microSD card reader, one that's only needed to set the date and time (which shouldn't be needed very often) and one which sets the desired sample period (anything from a sample every 5 seconds to a sample every few hours).

    The datafile is a simple CSV file, with the data formatted into columns, with the date and time and each sample value in each row. The file can be read into most spreadsheet programmes easily enough.

    The snag is that I've been distracted by drawing the plans for our new house and getting the new planning permission pack together. I have been looking across at the half-finished logger a little guiltily recently, so as soon as time permits I'll try and get back on to it and finish the display drive bit.
    • CommentAuthorowlman
    • CommentTimeJan 13th 2012
     
    There's someone on ebay, in Hong Kong selling digital temp readout devices complete with 2 wired probes. Have a look at item number 280798781199 at £12.90 and free p&p, do you think they might be worth a punt? Only trouble seems to be if you have two or three of these can you buy a housing for them and can the probes be lengthened. I asked the question to the seller but no reply.
    •  
      CommentAuthorJSHarris
    • CommentTimeJan 13th 2012
     
    <blockquote><cite>Posted By: owlman</cite>There's someone on ebay, in Hong Kong selling digital temp readout devices complete with 2 wired probes. Have a look at item number 280798781199 at £12.90 and free p&p, do you think they might be worth a punt? Only trouble seems to be if you have two or three of these can you buy a housing for them and can the probes be lengthened. I asked the question to the seller but no reply.</blockquote>

    At that price it might be worth getting one and taking the risk. My guess is that you may well be able to lengthen the probe without a significant problem with lost accuracy.
    • CommentAuthorpmusgrove
    • CommentTimeJan 13th 2012
     
    There is also a probe DS18B20 with real thick wires attached which even I could attach to something. I am a bit like JSH though and am too busy building the house at present to teach myself information systems again. So thanks owlman; I am going to invest in the HK readout device and will report back in due course.
    •  
      CommentAuthorJSHarris
    • CommentTimeJan 13th 2012 edited
     
    I found some cheaper single displays with remote sensors on ebay. How about this one for less than £2 including postage: http://www.ebay.com/itm/New-Digital-Thermometer-Temperature-Sensor-LCD-Display-/290431574781?pt=LH_DefaultDomain_0&hash=item439f1222fd
    • CommentAuthorEd Davies
    • CommentTimeJan 14th 2012
     
    SparkFun have just introduced these pre-wired and sealed 1-wire temperature sensors:

    http://www.sparkfun.com/products/11050

    Nothing magic about them but might be convenient for somebody who just wants to stick a bunch of sensors in place then think about how to use them later.
  1.  
    Posted By: Ed DaviesSparkFun have just introduced these pre-wired and sealed 1-wire temperature sensors:

    http://www.sparkfun.com/products/11050" >http://www.sparkfun.com/products/11050

    Nothing magic about them but might be convenient for somebody who just wants to stick a bunch of sensors in place then think about how to use them later.


    Similar is available on our favourite tat auction from Hong Kong:

    http://www.ebay.co.uk/itm/270844526066

    Essentially the same thing, albeit with slightly shorter cable, but signficantly cheaper.
    •  
      CommentAuthorJSHarris
    • CommentTimeJan 14th 2012
     
    I like SparkFun and have bought and used a fair bit of their stuff (the uSD card interface I'm using in the logger is one of theirs). They do often just market stuff that they buy in direct from China, though, so the chances are that both are of similar quality.

    having now sealed half a dozen or so DS18B20s on to cables as remote sensors I think I'd rather just buy the ready made ones, as the premium over the £1 or so per sensor I've been paying for bare sensors seems reasonable to me.
    •  
      CommentAuthorJSHarris
    • CommentTimeJan 14th 2012
     
    <blockquote><cite>Posted By: owlman</cite>There's someone on ebay, in Hong Kong selling digital temp readout devices complete with 2 wired probes. Have a look at item number 280798781199 at £12.90 and free p&p, do you think they might be worth a punt? Only trouble seems to be if you have two or three of these can you buy a housing for them and can the probes be lengthened. I asked the question to the seller but no reply.</blockquote>

    I've taken a punt and ordered a handful of the really cheap ones I linked to as an experiment (5 off displays and sensors came to just over £8 inc free postage!). I'll stick them in a box and see how they perform with extended sensor leads. If they are good enough for remote sensing around the house then they are probably the cheapest option. Since buying them I've found another place selling them for about £1.30 each, including free postage, which makes them cheaper than just buying a sensor.
    • CommentAuthorowlman
    • CommentTimeJan 14th 2012
     
    Posted By: JSHarris...............I've taken a punt and ordered a handful of the really cheap ones I linked to as an experiment (5 off displays and sensors came to just over £8 inc free postage!).

    How are you powering them JS? The listing doesn't seem to say. Do you intend lengthening the cable.
    •  
      CommentAuthorJSHarris
    • CommentTimeJan 14th 2012
     
    <blockquote><cite>Posted By: owlman</cite>Posted By: JSHarris...............I've taken a punt and ordered a handful of the really cheap ones I linked to as an experiment (5 off displays and sensors came to just over £8 inc free postage!).

    How are you powering them JS? The listing doesn't seem to say. Do you intend lengthening the cable.</blockquote>

    It looks like they have internal batteries in each module, probably little button cells. I'll see how long these last and might look at finding a way to add an external supply. I'll extend the cables to a few tens of metres if I can and see how that effects performance. They are cheap enough for me not to worry too much if they turn out to be rubbish!
    • CommentAuthorpmusgrove
    • CommentTimeJan 28th 2012
     
    Took delivery of a temperature reading device from Hong Kong yesterday and it works (after a little experimentation due to poor instructions). The device is Item title:Digital Temperature Panel Meter Monitor Thermometer °C- Item ID:280565422469 - Price: £12.90.

    It comes with 2 probes which are 0.5 degrees out with each other but once you make an allowance for that it seems to work alright.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 28th 2012
     
    Does it log the data to a memory card?
   
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