Vivarium Control

Discussion in 'The Projects Forum' started by erich_7719, Dec 17, 2009.

  1. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    First before I get into the full description of my project I would like to thank again those who have contributed to specific areas that I have asked for assistance.

    Thank you SgtWooki for your help and sorry once again for the confusion that came about from my miss reading one of your posts at

    Thank you MikeMl for your help seeing what my mind would not let me see at

    Now for the project:
    I have a Vivarium that has a working circuit and even though the circuit was not using a whole lot of energy I wanted to cut the energy consumption as much as possible. The original design is posted as “Vivarium electrical system V1.PNG”. Each relay consumes .4W and at 11 relays its 4.4W (like I said not a lot of energy).

    Ok, what does the circuit do…?
    We start with the Tank; that houses Plants, fish, amphibians and reptiles. The tank has a waterfall controlled by the “Main pump”, an Aquarium Light for day and night controlled by a single timer, a piezo disc “Fogger” controlled by another timer, Misting nozzles fed from a booster pump that gets water from a reverse osmosis (RO) reservoir and controlled by a temperature and humidity controller, there are four 4.5 inch fans for fresh air/cooling controlled by the same temperature and humidity controller.

    Within the stand is the RO System, by using a booster pump to take water from the main reservoir to feed the RO filters and charge the RO tank, there are pressure switches in place to control pressure in the system. The RO reservoir has two float switches to allow the water to get down to a certain level before refilling to another preset level, the flow is controlled by a solenoid valve between the RO tank and the RO reservoir. The Main tank reservoir is filled via a solenoid between my water main and the reservoir.

    The most current schematic is “Vivarium electrical system V8.PNG”.

    So the schematic Switch 1 is a key switch to manually disengage all logic connections (in essence to “Turn the power off”). Switches 2 and 3 are in the main tank reservoir and are there to turn off the main pump in the event of a refill failure, to prevent the pump from running dry. Switches 4 and 5 are in the RO reservoir to control the refillingof the RO reservoir. Switches 9 and 10 are the pressure switches going from a booster pump to the RO filters. Switches 11 and 12 are in the main tank, slightly higher than switches 2 and 3, to refill the main tank reservoir.

    Now that I believe I described every thing pertinent to the entire system I do have a couple of questions…
    1. The Darlington pair comprised of Q1 and Q2, I’m not sure how to calculate the worst case power consumption to see if the transistors I will be using will be sufficient or if I need bigger transistors.

    2. The NAND gates, I have them numbered in a manner that I think will give the most direct routs for the traces; Could some one be so kind as to look them over and let me know if this is the best configuration or not.

    3. Is there anywhere else anyone thinks a fuse should go?
    All Datasheets are attached in the RAR file.
    Thank you in advance,
  2. erich_7719

    Thread Starter Active Member

    Oct 14, 2009
    So taking R9, R10, R17, R18 R19, R20, R44,R45, R46, R47 and input for U9 (G3Ne-205T-US) I get 12V at .212A totaling 2.544W, which is more than the 625mW that each transistors (Q1 and Q2) can handle.

    The part that I am having issues calculating is that the MC14490 has an input current of .2-2.0μA do I put a current limiting resistor so that the input is no more than the maximum current? Do I connect them directly to Vdd directly and will have the .2 – 2.0μA? If the latter how do I add it in to figure out the maximum Wattage I’ll need for Q1 and Q2 to handle the circuit.