help with vivarium environment control circuit please?

Discussion in 'The Projects Forum' started by jamiespence, Feb 2, 2012.

  1. jamiespence

    Thread Starter New Member

    Feb 2, 2012
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    Hi there,

    Im new to this forum and i am trying to work out a way to control the vivariums i have setup at the moment. Im disabled, but was previously a mechanical/design engineer with a bit of sparky experiences to. the problem i am having is the thermostats avaliable to me ( i live in snowdonia national park, in north wales) tat are designed for reptile heating are very inaccurate and do not meet the requirement of my little reptiles.

    the main problem is that the thermostats im using( (Habistat 100's a 100w thermostat control avaliable from all reptile stores) for the heat matts in my 3'' viv are controled with a bi-metalic switch i think, and clicks on to full current when heat is needed and then off, The heat mats have a total of 19watts so not a loot really, but the matts are for a background heat idea for night times as there out put is fairly gently, the sensor is also rather inaccurate too, and allows for a massive 6-12 °F diference hen swiching on and off! The house that i live in is a 260 odd yaer old stone house so gets a bit cool at times!! So i have a 60W spot lamp to give the higher temperatures needed during the day, but the heat mats are still used during the day also if the temp is cooled in the house.

    Im ideally looking for help designing a cuircuit that would allow me to set a day temp and a lower night temp, that are more constant and to use the heat matts and lamp in the day for heat and only the matts att night with a 40w red bulb ( for veiwing nocturna behaviour). I would really appreciate any hep on this project as the equipment avaliable to me is rather limited and is very experncie and commercially priced to boot too!!

    My plan is to breed a miniture species of gecko in the future that are endangered as i am now an enviromental scientist due to illness and im planning on haveing 10 vivs in a stack/ rack formation, with ideally a heat meat controled for each viv seperately, with only heat matts but with the same distinct control over a day temp ( higher ) and night temp ( lower) i know that im asking alot from all of you and thankyou for your help in advance, if you would like any more information, drop me a line and i will try to help!!

    (P.s. the heat mats for the mini gecko bredding project will be 11w maximum due to small size of viv - these geckos are only 1 1/2 inchs fully grown so are really delicate ot temp spikes etc.) thanks again :)
     
  2. wayneh

    Expert

    Sep 9, 2010
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    I guess I see a choice between 2 strategies: 1) Improve the components in your existing control system, or 2) Build another control system.

    Having worked on a project involving tight temperature control, I'd be inclined to build my own, especially if you have experience with soldering and such, and enjoy the DIY aspects. If that doesn't sound so good, than strategy #1 might be a better approach.

    A really sweet system, IMHO, would use a LabJack U3HV or similar data acquisition device to take sensor data (eg. LM35 thermometer IC), any old computer to process all the data including clock time, and then relays under control of the computer via the LabJack. The relays could control lights, heaters and so on - anything needing AC power. This setup would easily allow for different chambers with different temps, lighting schedules, whatever you can imagine. You could also log data onto the computer, like a stripchart, if that would be interesting.
     
  3. crutschow

    Expert

    Mar 14, 2008
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    If you want to go the computer route, DATAQ also has a series of low cost interface modules. Learning the software to program them could be a little daunting if you haven't done programming before, but I'm sure you'll find it gratifying if you make the effort. Being able to view all the data over time and easily modify the control loop with software is a great plus.
     
  4. wayneh

    Expert

    Sep 9, 2010
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    Not to get too far off on a tangent, but one reason I was attracted to the LabJack was that I could use Visual Basic in Excel to talk with it. (It works with just about any language as long as you can write and read files.) I happened to have a long history with Excel and VB programming, so this was a big plus for me. I also played a bit with Objective C in XCode on my Mac, but this was foreign to me and I fell back to my old pal Excel.

    For one chamber, a computer is overkill, but for ten chambers, I think it looks pretty attractive. Just need to consider what happens after a power outage or a system failure.
     
  5. Markd77

    Senior Member

    Sep 7, 2009
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    If using a computer to control it I'd recommend Linux over Windows, because otherwise the "Blue Screen of Death" could take on a whole new meaning.
    Otherwise, if the sensor accuracy could be improved, it might be possible to use off the shelf components for the day / night cycle.
    You could have the heat mat and sensor permanently connected and have the heat bulb on a mains timer to go on during the day with it's own sensor set at a higher temperature. It would mean that the heat mat would turn itself off during the day, but if that's acceptable it's pretty easy.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    This is basically what I was thinking about as strategy #1 above. I was thinking about maybe simple lamp timers to achieve the day/night thing. Hacking the sensor to reduce hysteresis is just an unknown. Some systems even allow you to reduce hysteresis - it could be as easy as changing the settings.
     
  7. jamiespence

    Thread Starter New Member

    Feb 2, 2012
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    hi all,

    thanks for the replies all ready,, they are along the line i was thinking, actually making the circuit ( e.g slodering and fabrications skilll needed) iam good at the making!!lol! but just a bit clueless when it comes to the bits and peices need to make it work. the computer route seems a really good idea for the 10 setup ( or larger possibly!) I have an old pc that could be used for this project and i really like the data recording idea as this would make temp trend and brehaviour alot easier to observe over long periods of time. I think the pc has it, so now for the brains bit, Iused to programme CNC mills etc at college so have done some programming but this is a different ballgame im affraid. so which method is sipler from the replies i have received? The reason fr the post is trhe fact that at present 1 vivarium needs 4 plugs for differnt lights, heat mats,etc, and the tought of this times 10 was a scart prospect!!lol! so i thought if i could control the individual tanks with a simple setup controled all by the same source life would be much easier and i would get some plugs back too. thanks again for your help so far and hope that you can point me in the right direcion. ;-) jamie
     
  8. wayneh

    Expert

    Sep 9, 2010
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    You need to do some research into the various data acquisition options out there. Probably all of them include outputs under digital control, and analog outputs (voltage sources), in addition to analog and digital inputs.

    The top-of-the-line in this area is National Instruments and their LabView software. I judged this overkill for my needs, and I think it would be overkill for you as well. If you have funding and the key piece - somebody that knows how to lay out a system and get you started on the software - it could be worth looking into.

    You've already seen recommendations for LabView and Dataq, and my final choice came down to those two. (There are others,too.) I ultimately chose LabView because they're a bit more Mac-friendly and more versatile over all when it comes to programming, networking and so on. I also felt I was getting a good mix of input and output capabilities that were plenty for my needs without being a ridiculous overkill. I would feel confident tackling your project with a LabView device. Not to say it's easy, just that I'm certain it would work.
     
  9. crutschow

    Expert

    Mar 14, 2008
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    I believe you mean LabJack in the second paragraph? :confused:
     
  10. wayneh

    Expert

    Sep 9, 2010
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    Aww nuts, yes I did. LabJack was my choice.
     
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