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Posts posted by Codyhtml

  1. ok pins 1-9 of the 3915
    1| 3.8
    2|.4MV(basically zero)
    4|.4MV (same as 2)
    5|.64 V
    The Led's will light when not connected the the circuit
    i saw that i had connected the pot wrong i corrected that and the leds would light but my leds are just misc. ones from my drawer and one of my red leds meaning dry is on always i don't know if it is the leds or the circuit because the other leds just dim when i adjust the pot until they are barely visable
    i put in a switch to change between dot and bar and when it is in dot i don't see anything please help
    EDIT: when in dot i do see one green led (second from first meaning wet) when the probes are dry
    does the 3915 work high number down?

    whoops i realy messed this project up :(
    i connected pin 1 of the 3915 in the wrong spot i connected it next to the led for pin 10 on accident so that probably explanes some of the wierd things

  2. I don't think so except i didn't have a 510 ohm resistor and i made like a 500ohm or something so it should be fine and i think one other resistor i had to make my own but i came pretty close (by make my own i mean put two resistors in series)
    i found two mistakes that i thought i made and fixed them i thought i hooked up the leds backward but when i switched them it didn't fix anything (oopa i'm dumb i had forgot to connect one on the ics to ground so i did that and switched the leds but i realy had the leds on right  ::) in the first place  looks like its time two switch them again :( lol

  3. Ok Hi i guess you forgot that you helped me modify this and i don't have a led i have a led bargraph display lol
    my batterys are meashring a little over 5v
    on pin 6 i get1.3V on pin 3 i get1.6V on pin 8 i get .64 V on pin 11 i get 2.3V
    My ics are i'm guessing you want all of it so here it is
    That is how my other ic looks exactly (except for a little logo i can't type
    ps i don't feel any wormth on the ics if that helps

  4. Otherwise, if it were due to the dc charge, the battery would soon go dead and the compost process would get on it's way again.


    I do have to agree but for this year i'll make a second smaller compost pile and see if i can see a difference in them
  5. I got an idea what if I took a PVC pipe and put it in the corner of the compost pile and filled it with the same material as the other compost and put the probes into that. PVC is a great insulator and that might even help if any current went out of the bottom of the pipe and into the normal soil mabe it would make the worms want to go into the compost and stay there. I don't Know but what do you think about that idea. The pipe should dry out at about the same rate as the rest of the pile woulden't you think?

  6. Since your solar cells can output a max current of only 60mA and your Ni-Cads need 55mA for 14 hours, the Ni-Cads will never be fully charged and the charger is only 2 solar cells in series and in series with a diode. Any diode will be fine.

    that should be fine the main purpose of the solar cells is/was to extend the battery life. I can charge the ni-cads in a charger and the solar panels should keep them topped off for a while. Essentially making up for the extra draw of the bargraph/moving dot display.

    I guess i can experiment with the probes i don't see what would be a problem though

    For the charger just any general purpose diode right

    Thanks once again for your help if i get it all worked out mabe this could be another project since this is a fairly large mod :D
    EDIT: one more question the 2.5k resistor that I see in the circuit (on the LM3915) is that a POT if it is what kind linear, Logarithmic and what pot from here http://www.futurlec.com/Potentiometers.shtml would be the best to use?
  7. Ok thatks that is awsome thats the basics of what i need
    now how can i use two solar panels to charge 4 ni-cads such as what the solar yard lights do
    and can i have two or even three sets of probes to get a more acurate reading from the whole compost pile not just one spot?
    thatks for your help so far
    oh and in my schematic i left it a moving dot displayon purpose i decided that is all i need that way i save battery life and reduce power consumption

  8. ok great
    my solar panel gives about 4v in bright sun could I modify the the charging circuit (witch i might have to to disable the off at day and the on at night anyway) to use 3 double a cells or if I need to I could probably use two lights so I have 2 panels and 4 batteries what would be the easyest and best?
    and what about two sets of probes how easy/hard would that be?
    I just got another thought what if i ran the bargraph display off the solar panel that would give it 3.5-4V and it would not be on at night which is not needed

  9. Hi i've been inactive for a while but I have a question
    I would like to use the plants wattering watcher (1 or 2) to monitor the moisture level in a compost pile.
    but I need a little help modifying it idealy I would like to have a bar graph display (out of LEDS) Rather than a blinking led.  Battery life shoulden't be a problem I have an old solar yard light that I would like to incorperate in as the power source it has two rechargable ni-cad batterys 550mAh at 1.2 V
    Also as simple as possible would be nice if there is any was to simplify it that would be nice thanks

    ps. I tryed to make this post easy to read :D
    I just did some tests on the solar panel and i got this

  10. well what i understand in amps is how much current is being drawn through the wire right?
    and what i've heard is watts is what is being emited is that right?
    but what is realy confusing is how some power suplies such as inverters for your car to make mains and like solor cellls and stuff are rated in watts why would the power suply care how much current reaches it from what it put out? to a certin extent i mean you can't have like a 100watt light bulb conected to a solor cell or somthing rated for 5 watts dosent work that way but i still don't get why it is in watts not amps?

  11. ya just have the pir send its 3 second pulse to a 555 configured as a monostable multivibrator that sounds complicated but it realy isent the 555 basicly when it recieves a pulse it will send out a pulse of its own depending or the resistor capiccitor combination you made so just look in teh downloads section and there are some 555 calculators that will tell you what resistors and capictors and give you the circuit too just hook the out put from the pir to the trigger and the output on the 555 to the base of a NPN transistor through probably a 1k resistor most general purpous transistors will work and the collector of the transistor to the powersupply and the emiter to the relay hope i helped sorry for no periods but it is kind of early and hard for me to think right

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