Build an Enhanced Simple Bat Detector
...
The Parts List

The following table lists all of the parts used in building the enhanced version of the Simple Bat Detector. Where appropriate, I have given alternate sources. Web sites, mailing addresses, and phone numbers for the various sources are listed below the table. Adding up the costs of the various components listed gives a total bill of materials less than $35.00 For those who would like to skip the "scavenger hunt", a complete parts kit is available.

Ultrasonic Transducer ( 1 ea ) - Notes # 1, 2, 3 Mouser: P/N 255-400SR16 $ 4.90 each
6.8 mH Ferrite shielded detuning coil - Note # 3 Mouser: P/N 434-02-682J

$ 1.48 each
IC1 & 2 - LM386N-1 - amplifier ( 2 ea ) Radio Shack: P/N 276-1731 $ 1.19 each
IC3 - CD4024 - binary counter ( 1 ea ) Mouser: 511-4024 $ .55 each
Plastic Case with 9 volt battery clip
PacTec HM-9VB ( 1 ea )		 Mouser: P/N 616-61980 ( black )
Mouser: P/N 616-61985 ( bone )		 $ 5.14 each
$ 5.14 each
Printed Circuit Board ( 1 ea ) Custom Part - See Note # 4 $ 6.00 each
High Impedance Ceramic Earphone ( 1ea ) Mouser: P/N 25CR035 ( 3.5 mm plug ) $ 2.03 each
3.5 mm 3 conductor Phone Jack ( 1 ea ) Radio Shack: P/N 274-249 $ 1.99 pkg / 2
10 KOhm, PC mount variable resistor ( 1 ea ) Mouser: P/N 531-PT10V-10K $ .36 each
470uf, 16 volt electrolytic capacitor ( 1 ea ) Radio Shack: P/N 272-957 $ .99 each
220uf, 16 volt electrolytic capacitor ( 1 ea ) Radio Shack: P/N 272-956 $ .99 each
10 uf, 16 volt tantalum capacitor ( 2 ea ) Radio Shack: P/N 272-1436 $ .79 each
.047 uf, mylar capacitor ( 1 ea ) Radio Shack: P/N 272-1068 $ .69 pkg / 2
.022 uf, mylar capacitor ( 2 ea ) Radio Shack: P/N 272-1066 $ .69 pkg / 2
220 ohm, 1/4 watt resistor ( 1 ea ) Radio Shack: P/N 271-1313 $ .49 pkg / 5
Gain Resistors - 2 needed - see note # 1
150 ohm, 1/4 watt
1 K ohm, 1/4 watt
2.2 K ohm, 1/4 watt
3.3 K ohm, 1/4 watt
4.7 K ohm, 1/4 watt
Radio Shack: P/N 271-1312
Radio Shack: P/N 271-1321
Radio Shack: P/N 271-1325
Radio Shack: P/N 271-1328
Radio Shack: P/N 271-1330		 $ .49 pkg / 5

Notes:

  1. Different ultrasonic transducers require different gain settings, and some times additional components, to make them their most effective in the Simple Bat Detector. Be sure to read all notes for any transducer you select from this parts list ! Different values for the gain resistors R1 and R2 will be used for different transducers. If you have other sources for piezo transducers drop me a line. The transducer is the most critical part of the detector.

  2. Most of the low cost transducers available on the market are designed to work at about 40 KHz. Ultrasonic bat sounds can range anywhere from 8 to 120 KHz, so a choice of transducers will involve trade-offs. The bats I monitor generate most of their ultrasonic energy around 40 KHz, so a 40 KHz transducer is a good choice for me. Next to each of the listed transducers I've listed the frequency it is "tuned" for ( the frequency it is most sensitive to ). Below is a list of North American bats that match up best with the frequency ranges available.

    25 KHz big brown bat, pallid bat, spotted bat, big free-tailed bat
    40 KHz hoary bat, California myotis, small-footed myotis, Indiana myotis,
    little brown myotis, fringed myotis, long-legged myotis, Mexican free-tail
    50 KHz Indiana myotis, little brown myotis
    60 KHz southwestern myotis, long-eared myotis, eastern long-eared myotis,
    western pipistrelle

    The information used to layout the above table is from the BCI table on the Echolocation Calls of Common North
    American Bats    . ( Cited source: Fenton, M.B., and G.P. Bell. 1981. Recognition of species of insectivorous bats by
    their echolocation calls. J. Mamm., 62:233-243. )

  3. The Mouser Transducer listed in the parts list should have a 6.8 mH coil wired in parrallel across the back of the transducer for the best possible frequency response for the Simple Bat Detector. Wired in this way, the typical frequency response of the detector will cover 30-50 kHz with an added response node at 20 kHz. Generally, the R1 value for this transducer is 150 ohms. The R2 value will vary from 1K to 10K ohms depending on your specific transducer and wiring layout.

  4. In order to promote the availability of the Simple Bat Detector to those who don't have a means of producing printed circuit boards, I have had a number of boards commercially produced. I will pass them on at my cost plus postage. If you would like a printed circuit board, or if you run into difficulty with your bat detector project - email me.

Sources:

Tony Messina - email: T-Rex@ix.netcom.com - This parts list was last updated on December 3rd, 1999

Return to Build an Enhanced Simple Bat Detector Top Page