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Friday, 2 November 2012

Low Battery Indicator ( 9v ) Stripboard Veroboard Layout


I was in the middle of designing a little 9volt battery operated music thing and I thought it would be nice to have a little battery indicator to tell me when it was getting low.
Once I made it up I thought it might be a cool little thing to share on here so you could add it into stuff like guitar FX and so on.

it has 3 states:
1. if the battery is good then the LED doesn't light
2. between 7.5v and 6.4v the LED flashes to warn you it's getting low
3. below 6.4v the LED stays lit

I know there are specific ICs for this purpose however I like making my own "solutions"
Anyway hope you like it.




16 comments:

  1. Is it possible to swap the states 1 and 3?
    Then it could be used as an power LED with battery indicator.

    Greetings
    Rocken

    ReplyDelete
  2. yes you can but I will tell you how tomorrow - just so I can test the way I'm thinking works for you.
    basically you could invert the output high to a low which will reverse the 2 states
    but I will test it tomorrow and tell you on here.

    ReplyDelete
  3. I looked into it and it isn't really feasible with this particular circuit, I mean it's possible but you add either more expensive parts or considerable stripboard space.
    I may look into a making whole new battery monitor circuit that has a reverse status though

    ReplyDelete
  4. It would be great if you have the time for it. I think it could be a good mod for fx pedals. It could simply be inserted into the true bypass on the 3PDT as replacement for the standard power LED.

    Greetings
    Rocken

    ReplyDelete
  5. Hey Paul,
    I was wondering if we can change the lower limiting volatge means from 6.3 to 3v??how do we do that?

    ReplyDelete
  6. Here is a circuit which swaps the states 1 and 3:
    http://www.ecircuitslab.com/2011/06/low-battery-indicator-ii.html

    Greetings
    Rocken

    ReplyDelete
    Replies
    1. I did see that in EPE magazine a while ago but the problem with that is that it's too bloated with regulators and stuff

      I will get around to doing a reverse state one - it's just that it kind of seems redundant because if the battery is flat you will know before you have to look at an LED

      Delete
    2. Yes, there are way too much components in this circuit.
      It would be best if it begins to flash when the voltage drops below approx. 8 Volts. If the battery monitor is used in an effect pedal there must be enough time to finish the gig. But it should not wasting half full batteries.
      For testing I would use a trimmer which could be replaced by a fixed resistor.

      Greetings
      Rocken

      Delete
  7. I had one question about the diagram for this circuit - does the stripe in the symbols for D1 and D2 directly. indicate the relative position of the black stripes on these diodes, i.e., black stripe lead goes to pin c7 for D1 and black stripe lead goes to pin b13 for D2? I wasn't able to find this type of symbol for diodes on-line and wanted to be sure before I put this together.

    ReplyDelete
  8. hello paul,
    Can you give me the exact details about the components used in the circuit?
    It would be really helpful for me.

    ReplyDelete
    Replies
    1. the exact details are written on the layout

      Delete
    2. can you tell me the rating of the zener diode?

      Delete
    3. hey paul,
      one more clarification I need here. 5v1 ZD and In1418 are these both zener diodes?
      and can you tell me the specifications like break down voltage and other things for both of them?

      Delete
    4. all that info is in their datasheets. www.vishay.com/docs/85607/bzx85.pdf‎

      the 1N4148 is a small signal diode - it's very very common and very cheap - it's often a good idea to buy a thousand of them just to have because they get used so often.

      www.vishay.com/docs/81857/1n4148.pdf‎

      Delete