Water sensor/power shutoff *urgent help needed*

Discussion in 'The Projects Forum' started by kyroguy, Feb 18, 2011.

  1. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    It's hard to see under the tags on the resistors. I could be wrong but it look like the ground (row 26) and the unregulated + input (row 28) are both on your ground line.

    Are you getting 12V out of the regulator?
     
  2. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    I also noticed the transistor was hooked up wrong.

    The attached pic, shows elements as follows...
    Blue is the "Wall-Wart" (transistor, rectifier, and Cap.).
    Red is Voltage regulator
    Black is how the SSR should be hooked up to the transistor.
    In my circuit pictured I left out the indicator LED's and the de-bounce resistor and cap.
    and obviously the red and black lines represent the power rails.

    hopefully this helps some.
     
  3. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    Can you elaborate a bit on how the transistor is wrong? I am missing it.

    The two long yellow wires exiting on the right are going to the SSR. One is +12 and the other is hooked to the left most pin of the transistor with the flat side facing you. I know it is hard to see. My breadboarding skills are not great. I hate to cut the leads on the components down only to need them longer later when soldering it all together.
     
  4. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    The following image is from PG 1 of the data sheet that shows the collector on the right (flat side facing us), your image looks like the collector is connected to ground and the emitter is connected to the SSR output (which would make a voltage follower amplifier is you will).
    If I am seeing that right than all you have to do with the transistor is turn it around so the rounded side faces us (this will change the transistor to a switch).

    PG1.png

    Side note unless the tags are for you on the bread board it would be easier to see the connections with out them. Just an observation.
     
  5. kyroguy

    Thread Starter Member

    May 12, 2010
    77
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    Yes, the tags were partially my laziness. I have a hard time reading the color codes on the resistors so the tags just make it easier for me.

    Yes, sure enough the transistor is backwards. :-(

    Here are some clearer pics with the tags removed/moved. Thanks for your patience!

    [​IMG]

    [​IMG]
     
  6. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    Yes the transistor is backwards, and for s-n-g's pull out the LED with the black mounting ring on it. then test the circuit and let me know what you get.
     
  7. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    every thing else looks good.
     
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  8. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    Oh...my...god...it works!

    I assume it works anyway. The remaining LED functioned as I expected it to. It was off, then when on when the sensor touched water. It stayed on until the reset button was pushed. This is correct operation, right?

    Will the other LED be added back in at any point or are we proceeding with it like it is?

    Sorry for the delay, I had to pick my jaw up off the floor when it actually worked. ;-)
     
  9. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    The LED in parallel with the SSR should turn off when the sensor touches water than come back on when the reset button is pressed.

    Also the LED shouldn't had been the problem so it can go back in, if it doesn't work than we'll have to remove it for good or add another transistor to drive it.
     
  10. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    Just to be absolutely clear. The LED that we left in is the one that goes off when the sensor touches water, correct. Then when the reset is pushed it goes back on. If so, I have it working. As far as the LED with the black ring that was removed, it is messing stuff up when reinserted. I am ok with leaving it out, honestly. I am so happy to be to this point!
     
  11. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    Yes, that is the way it is supposed to work, and to prevent any hiccups be sure to tie R2 to ground. This will ensure that when the sensor does "low" that the AND input there will go low. IE..redundancy.
     
  12. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    A few other random questions.

    How many mA should the wall wart supply? I have been testing with a big one that supplies lots of power. In the final project I would like to use a smaller one. It is 350 mA. Is that enough?

    In the literature that came with the sensor it says it "must be mounted horizontally". Is this really necessary? How is your sensor mounted? During testing I have just been dipping it vertically and it has worked just fine.

    Thanks.
     
  13. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    My DVM is reading 51.4mA. The rule of thumb I see around here a lot is double, power supply double the required amperage and for resistors double the wattage, so with that said... Yes a 350mA will work.

    I have 4 in my sump, mounted Horizontally, to control water level and one in the hood, mounted Vertically, for when my over flow backs up.

    If you have very cool air in your house and get a lot of condensate on the hood sensor, that might trip the circuit since the point is facing down.
     
  14. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    Oh, so condensation is the reason for the horizontal mount. I couldn't figure it out otherwise. There is no reason (mechanically) that I could reason it must be mounted in a certain orientation.

    As far as my setup, condensation is never a problem. My light is suspended on legs above the open water. Lots of air circulation so regardless of temp I never get condensation.

    I am preparing to solder everything together later today. I am not anticipating any problems.

    Off topic, I wanted to show you my tank. I think it makes this project a little more real if you actually see where it is going to end up. I could show you the floor it is protecting too, but that probably isn't necessary. :) This is a little video I put together recently. I hope you enjoy it.

    http://www.youtube.com/watch?v=7-1oQMlFP5Y

    Hopefully today is the final day!!!!
     
  15. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    I like that black Clown fish.

    If there are no problems after the final assembly, it's been a pleasure working with you.
     
  16. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    Can't R2 be eliminated due to the fact that we scrapped the LED it was hooked to?
     
  17. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    yes, it can.
     
  18. kyroguy

    Thread Starter Member

    May 12, 2010
    77
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    Well, I have it completely assembled. The light is acting like it should but the relay doesn't seem to be working like it should. It doesn't cut the power at all. The power is allowed to flow regardless of the state of the circuit. Where should I start looking for the problem?
     
  19. kyroguy

    Thread Starter Member

    May 12, 2010
    77
    0
    I poked around with the volt meter. When the circuit should be allowing the power to flow the SSR is getting 12.05 volts. When the sensor touches water and the power should be cut, the SSR is getting 4.40 volts. I am wondering if this is not enough to flip the SSR to the off position?

    I plugged a lamp into the system to check its function. The lamp stays lit regardless of the state of the circuit or the sensor. But, when I unplug the wall wart and the circuit powers down, the lamp goes out. It is like the SSR is not getting the right signal to switch off.

    I hope all this helps you figure it out.
     
  20. erich_7719

    Active Member

    Oct 14, 2009
    92
    7
    do you have the SSR- pin 4? hooked up to ground or the collector?

    It should be to the collector.

    If not that please post the clearest pics you can.
     
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