Other Bat Detectors

Frequency Division Detector by Tony Messina (It is called The Enhanced Simple Bat Detector). This was the first detector kit that I built (in fact I built several and gave two to a school science program). I was so excited after building this kit that I had to go out every evening and listen to the bats as they flew around our garden. I use this detector often because it is small and sensitive to the bat calls.

The Belfry Bat Detector (also frequency division but uses a slightly different circuit). This detector has an additional amplifier stage so it has the effect of being very sensitive to the bat calls.

The Bat Scanner. This detector is a heterodyne type and also features a digital read-out. It will scan the frequency range and stop when it detects a bat, showing the frequency of the bat call you are receiving. Up/down buttons are used for manually selecting the frequency at which you wish to listen to the bats. It is very accurate, sensitive and quiet. The Bat Scanner comes from Tony Messina.

The Deluxe Bat Detector (another frequency division but again, uses a slightly different circuit) In mine I added a trim pot to the front end op amp feedback so I could tweek the gain to its maximum. This one comes from Electronic Goldmine.

Bat Chirp Waveform

Click waveform for a larger image and the recorded sound of the Bat Chirp

Here is a waveform of the Bat Chirp (it is recorded in stereo but each channel is the same). The Bat Chirp was in the bat simulation mode and the ultrasonic sounds were detected with the Digital Bat Scanner, and recorded to tape. The recording is then converted to digital in the computer. I can just see the bat as it makes an abrupt turn and dives for the unsuspecting insect.

The Ultrasonic Translator is a heterodyne circuit from Transtronics that came as a very inexpensive kit. It was easy to build and performs quite well even with some background noise. I installed the transducer in a PVC pipe fitting and put a jack on the side to plug it in. Also, I put in a headphone jack and a switch to select between the headphones and the internal speaker. Unfortunately,   I think this kit is no longer available.

Here is the first Bat Detector I used to listen to bats. However, it is not a bat detector but an Ultrasonic Leak Detector. When we first moved to our new home in the woods of Southern Oregon, I saw bats flying around in circles above our neighbor's horse pasture and in our yard. I tried my leak detector (an instrument I had used for the detection of manifold leaks in automotive repair and trouble diagnosis), and to my amazement, I heard my first bats. Even though there is some background noise it is very sensitive to the bat echo-location frequencies. That is what got me started in bat observations and bat detectors. I use it still, sometimes.