Bat Monitoring Project

Discussion in 'The Projects Forum' started by TheReremouse, Aug 11, 2013.

  1. TheReremouse

    Thread Starter New Member

    Aug 11, 2013
    4
    0
    Hi there, I hope that you can help me out with some advice - this is a bit of a strange request, and I'm sure its simple (ish) but I'm not a techie by any means.

    I work for the Bat Conservation Trust as a bat carer, and I am currently running a brand new 'flight cage', which is basically an aviary for bats where they can get ready for release back into the wild.

    I currently have 11 bats in the cage, and I need to get an idea of how many of the bats are using the cage (obviously they use it at night when I am not there) and which ones are just staying in the bat box.

    My hubby suggested using a beam-break sensor like this one but instead of it lighting up or sounding an alarm, I want it to count the times the beam is broken.

    The plan is to place it over the opening to the bat box, and ideally, when each bat comes out for the night, they will break the beam and get counted, so then I will know how many bats have been out.

    IDEALLY, I would link up two of the kits or arrange it so that it would only count when two beams are broken in a specific sequence, so that it counts bats as they come out of the box, but they don't count them a second time as they go into the box - so it is directional. (having said that this part is not essential, i would be delighted with just a counter).

    So if anyone can suggest a solution, I'd really appreciate any advice. I've got several brain cells knocking around so I think I could manage the wiring up, etc, but I don't know where to begin with adjusting the kit.

    Many thanks!!!
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,414
    3,353
    I know nothing about bats but here is an idea worth considering.
    I know bats navigate by echo location. I suspect that bats may have a signature frequency that you may able to detect with electronic equipment. It might be possible to identify which bat is coming and going. Just an idea.

    I'm no Batman nor Robin. Just call me MrChips.
     
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,979
    3,705
    You will have to be sure they are not going like a 'Bat out of Hell', otherwise, they will be too fast to detect.:D
     
  4. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
    Describe the exit/entrance from the bat box to the cage, and post a picture if you have one. What you want is doable given sufficient information. Is there a "tunnel" that the bats travel through to get out of the box?
     
  5. atferrari

    AAC Fanatic!

    Jan 6, 2004
    2,644
    759
    Be sincere; when you are in the cave the duo calls you Alfred. :p
     
  6. Metalmann

    Active Member

    Dec 8, 2012
    700
    223
    Sounds like a cool project, however I've noticed a sharp decrease in my local bat population in recent years, in northern IN.:mad:

    I love bats. Little mousy lookin' thangs.:cool::D
     
  7. Markd77

    Senior Member

    Sep 7, 2009
    2,803
    594
  8. TheReremouse

    Thread Starter New Member

    Aug 11, 2013
    4
    0
    Hi everyone, thanks for the replies - first, here is the bat box design:

    The front (outside) of the box:
    [​IMG]

    The view of the box entrance from below:
    [​IMG]

    The view of the interior of the bat box:
    [​IMG]

    Size of bat compared to the box:
    [​IMG]

    There are three of these boxes, but they are easy to block up so I can ensure the bats only use one of the boxes.

    As far as the echolocation goes, I have a couple of bat detectors but the problem is that the bats continue to echolocate as they fly around, and there is no way to separate the calls made by emerging bats and the calls coming from other parts of the cage.

    If I could count the beam breaks, and, say I know I started with 10 bats in the box, and I have 3 breaks, but I have 9 bats in there the next morning, then I know that the highest number of bats to have left the box is 2 (one went out and not back in, and one bat went out and back in again) - so you are right that I don't need the directional thing.

    Hope the photos help - basically the main part of the bat box is inside a shed, and the hole leads through to the outside of the shed, on the external wall. There's a couple of more photos to put it in context for you:

    Wall of the shed (inside the bigger flight cage) with the boxes on (dusters inside boxes to stop the bats flying out when I want them to stay in):

    [​IMG]

    And the inside of the flight cage itself where the bats practice flying:
    [​IMG]

    Thanks!!
     
  9. Shagas

    Active Member

    May 13, 2013
    802
    74
    Where do you live , Reremouse?
     
  10. TheReremouse

    Thread Starter New Member

    Aug 11, 2013
    4
    0
    In the West Midlands, UK.
     
  11. tracecom

    AAC Fanatic!

    Apr 16, 2010
    3,869
    1,393
  12. sirch2

    Well-Known Member

    Jan 21, 2013
    1,008
    351
    PIR may work as long as the bats are not likely to follow each other into the box too closely - but then broken beam may suffer from the same problem.

    Here's one from ebay UK http://www.ebay.co.uk/itm/HC-SR501-...sor-Arduino-Robotics-/171082585751#vi-content

    Obviously you will need more than just this - at least some kind of microprocessor (e.g. and Arduino), a display, batteries/power supply and an enclosure to keep it dry. Do you have any electronics knowledge?

    An alternative may be to rig up a mechanical counter. I'm assuming that the bats climb up into the box via the grooves on the wood. If so, if you could replace this with a piece of mesh hanging off a lever then when a bat climbs on it the lever could increment a tally counter. I'm guessing the bats are only a few grams so this could be a bit tricky to set up but may be easier than electronics depending on your skill set.
     
  13. LDC3

    Active Member

    Apr 27, 2013
    920
    160
    I'm guessing that the bats are already tagged. You could try an induction loop around the entrance and detect the metal bands on the bats. Would aluminum register a change in the induction loop?
     
  14. Potato Pudding

    Well-Known Member

    Jun 11, 2010
    684
    92
    The beam break detector you linked seems affordable. It would be easy enough to hack. Disconnect - unsolder the alarm since that is not needed and might disturb the bats. Connecting from the Led signal you can get a count. Before you get this detector, get your counter.

    For your counter, an easy type to hack are pedometers which can probably be had at a bargain shop for only a couple of pounds. You might find that a simple mechanical or wiring configuration will work with the pedometer without needing the photointerruptor.

    But you can do much fancier work with something like a raspberry pi, or an arduino.

    If you wanted to use those then there are all kinds of options and you can replace the photointerruptor with many types of parts that you might find scrap. You can have the count sent directly to a computer. Include a time stamp. Have a picture taken every time a bat leaves. Measure temperature. Measure light levels.

    Possibly you could collect grant money eligible types of research data.
     
  15. Potato Pudding

    Well-Known Member

    Jun 11, 2010
    684
    92
    I second the idea of using a mechanical trigger.

    I would suggest a lightweight wooden shingle as the landing dock. Have it on a set of lever arms. Have those lever arms spring supported. Connect the lever arms to a potentiometer (or variable capacitor like you find in old radio tuners might give a smoother signal.) Take a measure of the voltage changes on the potentiometer. You`ll get not just an idea of when there is bat moving in or out but with some calibration and design finesse, can actually measure their weight and tell from that if there is more than one.
     
  16. BC107C

    New Member

    Apr 3, 2011
    14
    1
    Can you (ie are you allowed) to attach an RFID tag to each bat? Than you can use an RFID reader inside the box or just at the exit. You will have now extensive real time data!

    The sensor at the exit will not always give you exact data, sometimes the animal can go out half way than back in. So You will need 2 sensors to detect the direction and completion.
    Anyway, nice challange, good luck!
     
  17. TheReremouse

    Thread Starter New Member

    Aug 11, 2013
    4
    0
    Wow, you guys are amazing - Thanks for all this - I will look at all these ideas tonight with my hubby and see which he thinks is the most feasible for us. To answer questions above: Yes, the bats are very light - 4-6 grams each; No, not allowed to tag them or attach anything without a special licence which I could get, but not in time for release. I have a couple of pedometers knocking around - I think the break beam attached to pedometer might do it - although I have been thinking about the raspberry pi thing too.... I could borrow a trail cam that takes a photo when it detects motion, but I'm not sure it is sensitive enough to pick up the bats.

    Thanks so much for the ideas!
     
Loading...