MidnightScience Ultrasonics

Dedicated to building and experimenting with ultrasound systems.

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 receiver kit to gain some familiarity with nature's ultrasound sources, signal pressure levels, piezo transducers, and amplifier gains required. Substantial gain is normally required, 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 test pressure commuications or bench link, using 40 kHz transmit and receive piezo transducers (PZTs) might be the ticket. See our parts page and kits for these.

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.

While bats are in hibernation this time of year in Kansas (Oct) , 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 the recorded windows media file.

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. While their transmitter sections are similar, the receivers are not. The Ultra-40 uses a direct conversion (heterodyne) receiver, similar to that for the Ultra-RX1. As such it is also ideal for listening to insects and bats. The Ultra-QP receiver uses frequency-division and only copies coherent ultrasounc, i.e. sine or square waves.

The Ultra-TR40, first demonstarted at the 4SQRP Convension in Branson (April 09), produces up to 3 mW of pressure. The Ultra-QP transmits about 1/2 that at most. However, the QP is designed to be used in a CW QSO Party, a round robin exchange of Morse Code based messages. It's great for learning the code in a group setting. See the kits page, tab at left, for more detail on these kits. See the article page for an in depth description of the 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.

The Ultra-TR40

The Ultra-QP