Renewable Energy Innovation

  • Increase font size
  • Default font size
  • Decrease font size
Error
  • Error loading component: com_contact, 1
Email Print

P1050170

Welcome to fascinating world of bats! This bat detector device converts ultrasonic sounds created by bats and convert them down to a lower frequency so that we humans can hear them.

Bats use ultra-sonic pulses to navigate and to detect prey. These pulses are very high pitch (around 5 times the maximum frequency humans can hear). This electronic circuit converts the high pitched sounds produced by bats to a human-audible level. It can also be used to listen to other high frequencies such as peeling sticky tape, compact fluorescent lights and power supplies.

An updated version of this kit is available here. It costs £20 for the kit, or £28 for the klit and an enclosure. This includes free potage within the UK.

No Image

Here are all the parts included in the kit - quite a few of them! (Please note the PCB has been re-designed in 2016 for ease of construction).

No Image

Here are the printed circuit boards from this kit.

No Image

A completed circuit board.

Another interesting use for this detector is to investigate devices which make a high frequency noise (in the region of 40-120kHz). You can hear compact fluorescent lights screaming away, the squeaks from sellotape as it is unwrapped and the high frequency power supplies which power the back-lights in phones and laptops.

Buy it here

A PCB and kit of electronic parts is available to buy for £20 (including delivery within the UK) via our sister company: The Curious Electric Company. This does not include the enclosure.

Please note: While not difficult to make, this kit does require quite a lot of soldering. It is recommended for people who have already done a bit of soldering and will take in the region of 1-4 hours to solder.

Edit 12/9/13: We have now designed a laser cut wooden enclosure for this kit. It can be purchased with the kit or on its own.Plans for this enclosure are available here.

Edit 4/11/16: This kit has been fully updated, re-deisgned to be easier to build and a much nicer enclosure designed.

Instructions

Here are the instructiosn for the most recent version (2016):

Here are the OLD bat detector instructions:

 

Enclosure design

A laser-cut enclosure is available for this kit and looks like this (more details are here):

No Image

No Image

Check out this awesome version made by Bart, who used the enclosure plans above but made it out of clear acrylic:

No Image

No Image

You can also fit the circuit into your own enclosure.

The circuit board was designed to fit into easily available 40mm push-fit plumbing fittings as shown here:

No Image

The finished unit, using 40mm plumbing tubing as a case.

 But other people have used different cases - please use whatever is available:

No Image

No Image

Here is anther bat listener built by Dick Stomp to test insect repellers (which emilt similar frequencies):

No Image

Another bat detector and enclosure:

No Image

No Image

A bat listener using the pipe and push-fit connections enclosure:

No Image

No Image

No Image

No Image

Great lettering and speaker grill on this case!

Comments   

 
#31 Matthew Little 2016-04-29 08:57
Hi Justin,
Hope that the kit worked for you, sorry for delay in replying.
The ultrasonic transducer does not matter which way around it is inserted.
You are right - the trim pot is adjsuting the sensitivity, not the frequency range. This circuit cannot easily vary the fequency detected. I will adjust the instructions accordingly.

Best regards,

Matt


Quoting Justin:
Hi!

Just got the kit and keen to get started :-). Couple of questions:
Does it matter which way round the ultrasonic receiver is installed? If yes which pin is ground?

In the instructions it says: "This device can be tuned to different frequencies of different species of bat". How do you do this? I am thinking that the 22k trimpot is there as a sensitivity adjuster and not as a frequency range adjuster.

Thanks!
Best regards
Justin
 
 
#30 Justin 2016-04-18 06:38
Hi!

Just got the kit and keen to get started :-). Couple of questions:
Does it matter which way round the ultrasonic receiver is installed? If yes which pin is ground?

In the instructions it says: "This device can be tuned to different frequencies of different species of bat". How do you do this? I am thinking that the 22k trimpot is there as a sensitivity adjuster and not as a frequency range adjuster.

Thanks!
Best regards
Justin
 
 
#29 Severine 2015-08-30 18:31
I forgot to say:

Thank you very much, and best regards!

Severine
 
 
#28 Severine 2015-08-30 18:27
Fantastic. Got the kit yesterday morning by the post, my husband and our 8-year old daughter assembled it this afternoon, fitted it in a 40 mm waste pipe as shown in the picture (excepted that it is shorter, 22 cm long in total) and it seems to be working fine. Looking towards hearing for the first time tonight the bats that we have seen in our garden!

Only one little comment regarding the instructions: the colour codes for some resistances are not right...
 
 
#27 Matthew Little 2015-05-29 08:39
Quoting David:
Hi, could the detector be modified to have a LCD freq display!!

Hi David,
Yes - I've been thinking about counting the frequency and displaying it for a while. If you count the pulses after the digital counter IC (pin 6 of the 4024) and then multiply that by 8 that will give the input frequency. This could be counted using a microcontroller (such as an Arduino) and then displayed after a bit of averaging.
Let me know if you build this - I'd love to see it.
When I have a moment I might try this out, as thinking it through, its not too difficult.
Have fun with you kit and thanks for your order.
Regards, Matt
 
 
#26 David 2015-05-28 19:41
Hi, could the detector be modified to have a LCD freq display!!
 
 
#25 Matthew Little 2014-12-04 18:20
Quoting Craig Hicks:
Hi

Won't any frequency corresponding to a multiple the 1:8 sampling rate disappear? Wouldn't the frequency response profile have valleys centered on these frequencies?

Craig

Hi Craig,
Thanks for your order.
As you have seen, this circuit is pretty simple in the way it works - the signal is amplified greatly and filtered (high pass and low pass). The amplified signal basically becomes a series of on/off pulses which are fed into the counter and every 8th pulse is outputted to the speaker.

So an input of 40kHz will give a 5kHz output.
Some frequency information is definitely lost with this rough way of frequency step-down. The reason that you dont get valleys of lost frequencies is that the signal is converted into an On/Off digital pulse train before the step down counter and the output is just a series of on/off clicks.

I have tried this unit directly against a much more expensive heterodyne frequency selectable unit (my partner uses these for professional bat surveys) and I could hear virtually no difference in the output sounds. In fact I would have said this kit was more sensitive. The main benifit of the professional unit is the frequency range selection, which aids with species selection.
Another issue with this kit which uses an ultrasonic receiver is the sensitivity range of the receiver, which has a peak around 40kHz, but again it works well over a very wide range of input signals as the analog signal is converted into a digital pulse train.

I hope that helps - basically this is a simple and low cost unit which will probably loose the fine detail of the Bat signals, but has worked very well in practice.

Regards, Matt
 
 
#24 Craig Hicks 2014-12-04 18:16
Hi

What can you say about the actual or theoretical frequency response of this system? I guess I would expect valleys around multiples of the 1/8 sampling frequency, but I'm really not an expert on this. I purchased it to see if I could hear the squirrels in the attic talking.
 
 
#23 Craig Hicks 2014-12-04 17:49
Hi

Won't any frequency corresponding to a multiple the 1:8 sampling rate disappear? Wouldn't the frequency response profile have valleys centered on these frequencies?

Craig
 
 
#22 Chris 2014-07-07 09:12
Just a belated note to say that I received the detector very promptly and within a couple of hours had built it with my 5 year old son having helped identify components and place on board. An hour or so afterwards the bats which visit our garden proved everything was working well. Andrew was delighted (even if rather tired) and took it to show his school friends the following morning! Many thanks.
 

Add comment