MidnightScience Ultrasonics

Dedicated to building and experimenting with ultrasound systems.

Phil Anderson, WØXI, will present "Locating Power Line Noise Sources, Pressure Leaks, and Listening to Bats & Insects with a 35-45 kHz Ultrasound Receiver" at the Huntsville, AL Hamfest at the Von Braun Center, Ausgust 21 & 22, 2010. Imagine building an ultrasonic receiver, mounting its piezo transducer at the focal point of a parabolic dish with attached pistol grip, and driving down the highway to find noisy power poles, hiking at night by the lake to listen to Big Brown bats chatting and hunting, or simply checking out your house or workshop with its many sources of ultrasound! Keep in mind that your dog and/or cat can already hear this stuff! Phil will demonstrate his Ultra-RX1 receiver with dish, outline how to hunt for noisy poles, play some audio recording of bats in flight, briefly describe piezo transducers and circuits used for ultrasound reception and transmission.

If ultrasound is a new topic for you, we suggest that you read our introductory articles on ultrasound. Just click on the articles tab at left. Keep in mind that we'll be adding more articles in the coming months. If you like to build and experiment, we suggest you get started by building our Ultra-RX1 or Ultra-RX2 receiver kit to gain some familiarity with nature's ultrasound sources, signal pressure levels, piezo transducers, and amplifier gains required. If you are interested in utilizing ultrasound to local radio interference due to AC power distribution sparking/arcing, take a look at our new parabolic dish kit.

Substantial gain is normally required with ultrasound equipment, challenging the designer to pay attention to circuit layout for stability. If a basic study of pressure waves is your goal, then wiring up a simple pressure commuications link, using 40 kHz transmit and receive piezo transducers (PZTs) might be the ticket. See our parts and kit pages for supplies.

The Ultra-RX1 Kit. This kit has been available for some months now; is popular and is a good place to start in exploring ultrasound. This receiver tunes an active part of the ultrasound band, ~35 to 50 kHz, with a 10 kHz audio bandwidth. Hence, while it is a heterodyne receiver, its output sounds similar to frequency division receivers when a coherent source is received. With the receiver, you'll hear not only bats but insects and rodents too. Click the "Kits" link on the left to learn more.

Thanks go to Philip Tate, M1GWZ (UK), Joe Eisenberg, NØNEB, and Bob Grove, W8JHD, for beta testing. 73s, Phil Anderson, WØXI.

Check out our new Parabolic Dish Kit. When trying to locate radio interference due to AC power distribution sparking, a dish is ideal, narrowing the search beam width and increasing signal volume. Click on the kits page at left for details.

Click here to listen to a recorded windows media file of a weak spark generated on the lab bench and copied by the Parabolic Dish with RX2 receiver at 40 feet.

We've added Marv Loftness's book, AC POWER INTERFERENCE HANDBOOK, to our catalog. Click on the ultrasonics parts page for details.

Thanks go to Chuck Hines and Randy Rathbun for manual proofing and beta testing the new Parabolic Dish kit and new Ultra-RX2 kit. Phil.

If amateur radio is your hobby, you might find sending and receiving Morse code via ultrasound interesting and fun. We have two kits that can do this, the Ultra-TR40 and the Ultra-QP. Thanks go to Joe Eisenberg, NØNEB, Jeff McCright, KDØGCL, Randy Rathbun, NVØU, and James Easter, WAØAFB for manual proofing and beta testing the TR40. 73s, Gentleman! Phil.

While bats are in hibernation during the winter; spring, summer, and fall are a good time to listen. In October (in Kansas), we took a walk around the block, hearing plenty of insects buzzing and chirping, using the Ultra-RX1 receiver and a pair of 25-ohm Sony headphones. Click here to listen to a recorded windows media file.