Bat detector fun
I recently purchased a digital bat detector from Peersonic. It samples directly at 384 kHz with an ultrasonic microphone and you can listen to the sound slowed down by up to a factor of 20. It will write a sound file to an SD card and you can connect to a PC with USB to download the files. You can process them with a program like Audacity. It is a really cool gadget to have.
Since the bats near us are taking a well-earned winter rest I've been listening to other things. Jingly keys slowed down sound like really huge keys. Surprisingly, a nice source of ultrasound seems to be a fast running stream of water from a tap into a metal sink. I measured some fountains and they also had a peak around 30kHz.
Biting the hand that feeds IT
