The following parts & books are provided for your convenience in prototyping and exploring ultrasound.
AC POWER INTERFERENCE HANDBOOK
by Marv Loftness, KB7KK
This is the third edition of Marv's book, spanning 16 chapters. It is the definite work for locating RF interference due to sparking on AC distribution systems. Marv is an EMC engineer with many years of experience in the power industry. He is the inventor of a number techniques for locating RF interference. Here are some chapter titles:
Causes & Effects
The Corona source
Noise Propagation
Rapid Noise-Source Locating
RFI Sources and Correction
Some Locating Methods for Radio Amateurs
Power Line Interference - Sounds, Patters and Myths
and more
Thumb Pot to vary RX1 front end gain
Install this thumbpot in order to adjust the front end gain of the Ultra-RX1.
Useful when adding the RX1 to the parabolic dish assembly.
40 and 25 kHz Transmit Piezo Transducers
This Kobitone transmit PZT, #400ST16, is ideal for experimentation, and is used in our ULTRA-TEST-GEN1 Kit. It has a diameter of 0.65 and a depth of 0.50 inches. The two pins are spaced 0.4 inches apart and have a diameter of 40 mils. The center frequency of emitted pressure is 40.0 kHz +/- 1.0 kHz. The sound pressure level (SPL) emitted at the center frequency is specified at 119 dB relative to the threshold of hearing, 20 uPa. Bandwidth is specified as -6dB at +/- 2 kHz. Allowable input power is 0.2W, and package capacitance is 2.4 nF +/- 20% at 1 kHz. See our article "40 kHz Piezo Transducers," which describes typical values for PZT parameters.
40 AND 25 kHz Receive Piezo Transducers
This Kobitone receiver PZT, #400SR16, is ideal for experimentation, and is used in our ULTRA-RX1 Receiver Kit and ULTRA RX TEST JIG1 Kit. It has a diameter of 0.65 and a depth of 0.50 inches. The two pins are spaced 0.4 inches apart and have a diameter of 40 mils. The center frequency of received pressure is 40.0 kHz +/- 1.0 kHz. Sensitivity - the voltage received at the center frequency - is specified to be -65 dB relative to 1V per ubar. Bandwidth is specified as -6dB at +/- 2.5 kHz. See our article "40 kHz Piezo Transducers," which describes typical values for PZT parameters.
6.8mH Choke
This Fastron ferrite choke, #07MFG-682X-50, has an inductance of 6.8 mH and is useful in broad-banding the response of some 40 kHz PZTs. It has two 0.025 inch diameter radial leads spaced at 0.150 inches and has a body diameter and height of 0.35 and 0.46 inches.
High GBP 8-Dip OP-AMP
The high gain bandwidth product (GBP) OP-AMP, NJM4580DD, is ideal for 40 kHz work. While transistors can be used in circuits at 40 kHz, it is often useful to use op-amps, i.e. for making synthetic inductors. Typical audio op-amps don't have an adequate GBP for 40 kHz circuits; and, we suggest op-amps with a GBP of at least 10 MHz. The JRC4580DD in an 8-DIP package meets this need.
Pin assignments are the same as the generic 8-DIP dual op-amp IC:
Pin 1 = U1 out;
Pin 2 = "-" U1 input;
Pin 3 = "+" U1 input;
Pin 4 = Minus Supply or ground (for single-supply operation);
Pin 5 = "+" U2 input;
Pin 6 = "-" U2 input;
Pin 7 = U2 out;
Pin 8 = VCC (+ supply).
40 kHz Capable Ferrite Toroid: FT-87A-J
Ferrite toroids are often used as a form for winding a coil or broadband transformer, enabling a large inductance or xfmr in a small space. The FT-87A-J is suitable for 20 kHz to 1 MHz electronic circuits, corresponding to ultrasonic work. For a desired inductance, the number of turns required is calculated as follows:
For the FT-87A-J, N (# turns) = 1000*SQRT(L(in mH)/6040). Hence 18 turns provides for an L of 2 mH. The equation varies for different sizes and types of ferrite materials.
The core has the following dimensions in inches: OD, 0.870; ID 0.540, and height, 0.500.
