Trap circuit help pls...

Discussion in 'The Projects Forum' started by bio88, Jul 10, 2011.

  1. bio88

    Thread Starter Member

    Feb 17, 2011
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    I invented a high tech bird trap that uses an IR break beam to trigger a small solenoid tethered to a battery box with a SLA 12V Batt.

    The electronics portion was subcontracted out to a friend (I'm a noob with circuit skills) and what he delivered was a nice package. However,

    I'm getting only about 36 hours battery time in armed mode. There needs to be more like 100 hours.

    If a SLA is used indoors to power a trap does it have to meet a code? I don't want to burn a place down or anything. Maybe the battery box needs to be rated or something...


    Any help appreciated -
     
    Last edited: Jul 10, 2011
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Can you post battery capacity?

    Which part in your circuit consumes the most current in armed mode?

    If the beam is always on, I could imagine that it's the beam that consumes most. If it's always on, then you could try to use short pulses of a few kHz to shorten the time the IR transmitter remains ON.
     
  3. bio88

    Thread Starter Member

    Feb 17, 2011
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    Battery is one of those used in bugler alarm systems. I think it is 5 ah? I think the circuit is based on this circuit.
     
  4. SgtWookie

    Expert

    Jul 17, 2007
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    Well, unfortunately it's going to be difficult to offer much advice without access to a schematic and parts list, but you probably don't want to place them in the public domain by uploading them here.

    If a solenoid is being kept energized the entire time that the trap is armed, then I'll suggest that the design needs a bit of re-work. Solenoids and relays are power-gobbling devices; but in your project a solenoid or something similar will be necessary to spring the trap.

    Without knowing anything but what you've said so far about the solenoid and IR break beam, I'd approach the project by using a very efficient DC-DC converter to power a microcontroller that spends most of its' time in low-power mode; waking up periodically to turn on the IR emitter and detector to see if the beam is broken or the battery is getting low. If the beam is broken or the battery is low, the trap is sprung and battery disconnected. Just a "guesstimate", but the average current draw from such an arrangement should be just a few mA's, which would not be much of a drain on an SLA battery.

    As far as SLA's being used indoors - they are all the time. Every UPS (uninterruptible power supply) has one or more SLA inside. I'd suggest that you use AGM batteries, as if the case gets ruptured, there is nothing to spill. Also, AGM batteries can be charged more quickly than gel-cell, thus can be returned to service more quickly.
     
  5. bio88

    Thread Starter Member

    Feb 17, 2011
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    Thanks - you can visit the link at the start of the thread and from there see the trap in action on youtube.

    The small coil solenoid is the trip - it operates for say, 5 seconds. The break beam needs to be always on while trap is armed. Bird comes to feed, breaks beam, trap captures bird.

    Also, there is a remote keyfob operated arm option. I believe that uses some draw as well.

    Thanks for the info - it is good to know when I get back with my electronics partner.
     
  6. wayneh

    Expert

    Sep 9, 2010
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    If your circuit really is like that one posted, a big energy waster is the lefthand side R1. Whatever power is going to the LED, ~3X that is being burnt off as heat there, to drop the 12V down to ~3V for the LED. I'm not saying you can just remove it, since that would blow the LED L1. Using an efficient DC-DC converter instead of a resistor, as suggested, ought to give you a big improvement. Modulating L1 has also been suggested, and would also give a big boost in life.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    My reply took so long that I didn't see the previous two replies.

    The circuit you linked to would not be good to use in an environment that would have natural or artificial lighting, as the ambient lighting could keep the circuit from triggering.

    If IR detection is going to be used, you'd need something more like the 36kHz to 42kHz receivers that are used for TV remote controls; as they can differentiate between a pulsed IR emitter and flickering ambient light.

    The circuit you linked to would have a constant ~25mA current drain for the IR emitter alone. The IR detector and R2 consume another ~1.26mA when nothing is blocking the IR emitter.

    With a 4AH battery and no other load, that should give a maximum run-time of around 150 hours before the battery is completely discharged (not a good idea; service life will be very short) or about 45 hours until the battery is discharged to 70% capacity (for normal service life).
     
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