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Thread: Sensor Location, new system,

  1. #1
    Automated Home Jr Member RichardC's Avatar
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    Default Sensor Location, new system,

    Been reading the blog "At the factory of idiot dreams" which has been very interesting.

    I have permission from SWMBO who has been encouraged by a small demo X-10 system. To buy a "small" amount of bits to do a proof of concept of a HA control system. I have chosen to get Idratek.

    We are currently refitting two bathrooms. Installing underfloor wet heating. So I am looking at controlling the temperature in the bathroom, plus monitoring humidity. I think light level would also be usefull.

    PIR would be good, but as we have a cat running about the house, I think I may need to install a pet style IR sensor and run that to an input on say a LTH-001.

    To measure temperature I would need to put this sensor at mid height in the room. Or if it's higher, would putting an off-set on the sensor work OK?

    Anything to watch with putting these sensors in a moist enviroment. They are ELV, I guess keeping them slightly out of the way would be good, stop someone dripping into the vent holes?

    To get an outside sensor say a LTH-001 then I would add 15 quid to it's price and order it as a LTH-X01? Just a bit confused?

    Many questions, sorry!

    Cheers

    Rich

  2. #2
    Automated Home Ninja Andrew Millne's Avatar
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    Quote Originally Posted by RichardC View Post
    To measure temperature I would need to put this sensor at mid height in the room. Or if it's higher, would putting an off-set on the sensor work OK?
    I took the same approach as you initially by doing one bedroom in order to test viability. I used a single DRB module in place of the light switch and a LTH module in the ceiling. I then later added a DRH module at socket level to control an electric heater. I have a small 1.5c offset on the LTH which I found works well although if your heater/radiator is directly beneath then this will be less than an ideal situation. With underfloor heating I don't foresee you having any problems. Personally I am more interested in getting a useable proxy reading than a totally accurate measurement.

    It is also useful to remember that there are a lot of factors besides temperature that influence comfort levels so yet another reason why I feel a useful proxy is more important than getting too hung up on accuracy.

    In my most recently altered bedroom I opted for a DFP panel which is at shoulder height in place of the light switch which gives a more accurate and useable reading. Now I am sure that the Idratek system is useable by the rest of the household and visitors I am less inclined to stick with "traditional" light switch locations and I am considering moving this to above a bedside cabinet.

    There is an interesting discussion on black bulb sensing here which may also be of interest http://www.automatedhome.co.uk/vbull...ead.php?t=2203

    Quote Originally Posted by RichardC View Post
    Anything to watch with putting these sensors in a moist enviroment. They are ELV, I guess keeping them slightly out of the way would be good, stop someone dripping into the vent holes?
    I am using a DFP in my bathroom which is within regulations however you should note that switching of any LV (Not ELV) should be done elsewhere.

    Perhaps ceiling mounting would be the best option for other modules?

    Quote Originally Posted by RichardC View Post
    To get an outside sensor say a LTH-001 then I would add 15 quid to it's price and order it as a LTH-X01? Just a bit confused?
    Yes thats right.

  3. #3
    Moderator Gumby's Avatar
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    Quote Originally Posted by RichardC View Post
    Been reading the blog "At the factory of idiot dreams" which has been very interesting.
    Glad you enjoyed it

    Quote Originally Posted by RichardC View Post
    I have permission from SWMBO who has been encouraged by a small demo X-10 system. To buy a "small" amount of bits to do a proof of concept of a HA control system. I have chosen to get Idratek.
    Excellent choice

    Quote Originally Posted by RichardC View Post
    We are currently refitting two bathrooms. Installing underfloor wet heating. So I am looking at controlling the temperature in the bathroom, plus monitoring humidity. I think light level would also be usefull.
    Bathrooms are fun. Building regs apply so don't forget to check with building control or work with you electrician.

    The new(ish) combined PIR Light level sensor, temp and humidity sensor sounds ideal. Also it's time to decide whether you might put ceiling speakers in connected to sound system for relaxing soaks in the bath. If so you might want an IR RX as well. And think through your lighting scheme and whether you want "mood" lighting and hence need for dimmers etc.

    Since you are monitoring humidity, you might as well control your extraction fan and save on buying a (rubbish) humidistat controlled one. You can use Cortex to also run it at other times for, ermm, odour control.

    Quote Originally Posted by RichardC View Post
    PIR would be good, but as we have a cat running about the house, I think I may need to install a pet style IR sensor and run that to an input on say a LTH-001.
    Not having pets I can't comment on how pet sensitive the Idratek sensors are. If you have, say, an SLH controlling your fan you will have additional inputs there.

    Also check previous threads, because pet sensitivity has come up before.

    Quote Originally Posted by RichardC View Post
    To measure temperature I would need to put this sensor at mid height in the room. Or if it's higher, would putting an off-set on the sensor work OK?
    Common practice says they should be put at shoulder height. But given all the different air currents through a room I am unconvinced that it really matters somewhere like a bathroom where you would typically be in a variety of locations. You can apply an offset, or you can simply adjust the heating profile until it's generally comfortable and not worry about the nominal temperature value. Since a ceiling mounted one will read higher, you'll also be able to say "Look, it's not cold in here, it's reading 22 degrees, I'm not turning up the heating. Put on another jumper"

    If you do mount them in the ceiling, be careful to block up the holes in the back box to avoid cold air falling down through the module. And you may also have to think about the consequences of penetrating the ceiling in the same way as for downlighters. Back boxes with intumescent gaskets and retrofit gaskets are available to address this.

    Quote Originally Posted by RichardC View Post
    Anything to watch with putting these sensors in a moist enviroment. They are ELV, I guess keeping them slightly out of the way would be good, stop someone dripping into the vent holes?
    They are not splash-proof so need to be out of splash zones. Also probably wise not to put them directly over obvious sources of steam, like taps and shower heads. You could also consider proxy controls connected to remote DIO. I have a plan to sense my sink waste position to turn on the over sink lighting, for example.

    The regulations depend somewhat on whether they are SELV or PELV. Since it's not absolutely clear what the status is, treat them as PELV.
    ----------------------
    www.gumbrell.com

  4. #4
    Automated Home Jr Member
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    Richard,

    My system is similar to what is being discussed ... we have a cat who triggers the IDRATEK PIRs quite well. We tried at first blanking them off (with blue tack) to stop them seeing anything at floor level, but eventually we just had to modify where and what type of automation is acheived. It works for us very well.

    As you say pet proof ones may be better, but i have no experience of these.

    Regards,
    Peter.

    PS - I have got revenge a few times though using Cortex ... check the cameras, see where he is, remotely speak a message through that room intercom and watch him look very confused. :-) He has learnt that one now though.

  5. #5
    Automated Home Guru JonS's Avatar
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    We have a cat and small children. I have installed Active8 PIRs which have jumpers to set the weight of pet, i.e. how big an object to ignore. Then in Cortex I removed the MFP/DFP PIR from the room connections and replace with the digital input the PIR is connected to.
    I selected Active8 as they offered a couple of weight settings and these were quite low compared to most, so more suitable for a cat rather than large dog which would also ignore children, & they were fairly cheap ~6+vat from Alert Electrical.
    In practice the response to children and adults was compromised by having the ~15kg threshold so I now have them set in the "normal" mode. They are not as sensitve as the Idratek ones but this means that the cat rarely triggers the room occupancy but toddlers and bigger do. In one room the PIR is never activated by the cat so some of it is due to positioning and proximity of sensor to cat. I think the next refinement would be a dual tech motion detector but these are much more expensive and so far not worth it.
    HTH
    Last edited by JonS; 18th March 2009 at 02:05 PM. Reason: PIR detail
    JonS

  6. #6
    Automated Home Jr Member RichardC's Avatar
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    Thanks very much for the advice. I'm now getting on with starting to install Idratek now.

    Sorry for the delay in reply. Didn't realise how much time is taken up sorting out getting married, plus combining two houses into one! I have lost my home cinema room and been told to get rid of a lot of my "it will be useful one day" grade stuff.

    Only ordered the Idratek kit about a month back and just have started fitting it around the house. So have been going through some old posts to the forum to get ideas for things to try.

    Yesterday, fitted the outside humidity, temperature and light module. Started monitoring some of my electricity usage, in a trial of several electricity meters. Before I buy another 10 or so.

    Last night my wife asked when she can have access to the cortex screen on her computer! (Should I be worried!)

    I have just got two movement detectors, one a pet tolerant PIR, the other a tritech pet tolerant PIR. Plus 4 12v smoke detectors. So will now be working on motion sensitive lighting and see how it goes.

    Tried the squeezebox module last night and in playing with the kit got one of my squeeseboxes into a right sulk. So will be chewing at that problem now.

    Have taken lots of pictures and hope to get a blog going.

  7. #7
    Automated Home Jr Member
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    Hi folks - I've been lurking for a while and have had a play with - sorry, serious evaluation of - an Idratek starter kit and am impressed enough to be currently wiring my house ready to take Idratek. Actually the electricians are doing all the hard work of the first fix (and are intrigued by the system).

    The house is being totally refurbished so their job is being made easier by having no furniture, carpets, or even ceilings in many rooms and therefore easy access to floor/ceiling voids. In fact they're getting on so well it's about time I ordered the Idratek bits and pieces!

    I am replying to this thread primarily because of the PIR issues - I too have a cat, so don't want it triggering PIRs and turning the lights on unnecessarily.

    My starting point for automation will be the lighting in the hall, stairs and landing (it's a fairly large Victorian place with 4 flights of stairs). Are PIRs the best way to go? I have read that the pet-immune type effectively ignore ground-level movements (since they can't actually tell how much something weighs). So I'm worried that as the cat comes down the stairs, it will be in the main scanning area of the PIR, rather than at the floor level it is set to ignore, rendering the pet-immune function useless.

    Would it be better to use pressure pads or other sensors, like a beam-break? What is the longevity of pressure pads like? Are the dual-tech PIR and microwave sensors significantly better than the normal PIR ones?

    Thanks

    Clive

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