This year I have made most of my Xmas presents, using a number of the facilities at Nottingham Hackspace and at my own work studio.
For my Dad I built a bat detector. This is a device which will convert ultrasonic sounds created by bats and convert them down to a lower frequency so that we humans can hear them.
I had been wanting to build one for a while and then saw a version in the November edition of Elektor electronics magazine. I produced a slightly different PCB design using KiCAD and produced the PCBs as a skill share session at Nottingham hackspace.
What has been intreresting has been the amount of devices which make a high frequency noise (in the region of 40-120kHz). You can hear compact flourescent lights screaming away, the squeeks from sellotape as it is unwrapped and the high frequency power supplies which power the backlights in phones and laptops. I’ve not heard any bats yet as they hibernate for winter.
A few people have shown an interest in making one of these, so I will be running a session building them sometime in the New Year.
The finished unit, using 40mm plumbing tubing as a case.
The printed circuit board, made at Nottingham hackspace. The circuit design is from Elektor electronics.
40mm plumbing fittings used as the case. These include a section of pipe, two couplers and two end stops.
The end stops were drilled out for the sensor and the loudspeaker.
Pieces of brass grill are used to protect the sensor and speaker.
The sensor can be seen through the brass grill at the end of the device. The 40mm speaker fits perfectly within the 40mm pipe, using the coupler to hold it.
A frequency adjustment can be made to tune the device to different species of bat. In the future this will be a dial.
A PCB and kit of electronic parts is available to buy for £20 (including delivery within the UK). This does not include the enclosure. Please click the Buy Now button to purchase: