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.
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).
Here are the printed circuit boards from this kit.
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.
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 4/11/16: This kit has been fully updated, re-deisgned to be easier to build and a much nicer enclosure designed.
Here are the instructiosn for the most recent version (2016):
Here are the OLD bat detector instructions:
A laser-cut enclosure is available for this kit and looks like this (more details are here):
Check out this awesome version made by Bart, who used the enclosure plans above but made it out of clear acrylic:
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:
The finished unit, using 40mm plumbing tubing as a case.
But other people have used different cases - please use whatever is available:
Here is anther bat listener built by Dick Stomp to test insect repellers (which emilt similar frequencies):
Another bat detector and enclosure:
A bat listener using the pipe and push-fit connections enclosure:
Great lettering and speaker grill on this case!