BACKGROUND:
It's time to think "outside the box"
This "kitset" may hold some interest for those who like to experiment or discover the world of ultrasonic sounds, both from living creatures and equipment such as motors etc. My interest was as a custom test instrument so that I could listen to motor bearing noise (often way above the normal audible frequency range for humans) and at times it came in handy locating high voltage arcing, without having to turn the lights off! Instead of seeing and smelling the ozone odour, I could hear the arcing taking place. I actually modified one of these kitsets slightly to suit my purposes, nothing dramatic, but I created a tube arrangement which sat on the front of the microphone to act as a "sound waves" focus. The native angle of response of these ultrasonic transducers is around 30 degrees and I wanted to narrow it down a bit.
Oh, I forgot ... you can listen to "bat sounds" if that is your thing (we have thousands of bats around Western Sydney in the warmer months and I had no desire to listen to their constant screeching!)
This kitset is almost completely assembled when supplied, nice SMD based main board and it is basically just a case of plugging in the correct connectors and you are in business!
This is a quality designed product which is intended for those who have an understanding of electronic principles so that you can understand how this works and this is evidenced by the well written booklet (not Chinglish) which explains ultrasonic sound waves in detail, the operating principles of this detector and even supplies a full schematic diagram and board layout diagram.
Designed in United Kingdom, the functioning of this detector revolves around the clever use of a CD2003 LSI, this chip is actually a single chip AM/FM radio. The design of this detector works by mixing the ultrasonic sound waves detected by the microphone with a local oscillator signal (555 timer chip is used here), producing a beat signal. This signal is then sent to a common LM386 low power audio amplifier.
Just two user controls, the volume and a control of the "beat frequency"
Now I was working around the 40Khz region so this microphone suited my purposes fine (roughly 38KHz ~ 45KHz 3dB points) but if you were going to take a listen on much higher frequencies, say 100KHz or above then another microphone would need to be found - this one just isn't designed for those higher frequencies. This would particularly apply if listening to some animals which emit ultrasonic sound waves as a means for communication, often way above 40KHz
This is what attracted me to this kitset, there was a time when I wanted to investigate some ultrasonic "noise" and this kit fits the bill perfectly. I actually had two of these kits, one was shifted to a "proper" metal enclosure once I had checked that the detector would suit my purposes ... I have kept that unit.
Seems almost criminal to call this a "kitset" ... there are no "spring connections" nor soldering required, plug in 4x sets of connectors and you are in business!
This kitset is the "spare one" that I originally imported from UK (more cost effective shipping to send two) that I have opened, connected the speaker, battery & microphone to the main board to ensure it is working properly and then as all was well, I have reboxed it as I had no need for this second unit.
This advertisement is in the process of "being born" ... it should be complete in the next few days (around 29th July 2026)
