Excellent, Cheap Sonar Transducer.
bobledoux
Posts: 187
Allelectronics.com is selling the XDR-24 transducer at 10 for $10.
These are excellent units. So much so I bought 30 of them for my robotics experimentation. They are extremely sharp, requiring a signal between 23.5 and 24.6khz. Units can be used as both receiver and transmitter. I set up a test rail, spacing two transducers 30cm apart. With a square wave of 5 volts fed into one transducer I read a signal of 60mv on the second transducer, used as a receiver.
In my application my receiver is an op amp with gain of 10 feeding an LM567 tone decoder. With 1.2 volts peak-to-peak, fed into the sending transducer, the tone decoder recogizes the signal at the distance of 1.5 meters, with the receiving transducer set at an angle of 45 degrees to the sender. These results assume some fine tuning of LM567 components.
Consider this component, especially if you need to build a low cost, omnidirectional beacon system.
These are excellent units. So much so I bought 30 of them for my robotics experimentation. They are extremely sharp, requiring a signal between 23.5 and 24.6khz. Units can be used as both receiver and transmitter. I set up a test rail, spacing two transducers 30cm apart. With a square wave of 5 volts fed into one transducer I read a signal of 60mv on the second transducer, used as a receiver.
In my application my receiver is an op amp with gain of 10 feeding an LM567 tone decoder. With 1.2 volts peak-to-peak, fed into the sending transducer, the tone decoder recogizes the signal at the distance of 1.5 meters, with the receiving transducer set at an angle of 45 degrees to the sender. These results assume some fine tuning of LM567 components.
Consider this component, especially if you need to build a low cost, omnidirectional beacon system.
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Beau Schwabe - Mask Designer III
National Semiconductor Corporation
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Pin 3 of the opamp is fed with a voltage divider. The 15uf cap removed some peak fuzziness seen in the scope trace. Voltage gain is 10. Opamp .1 coupling caps are required and work well at 24Khz. LM567 has .1 caps on pins 1 and 2 to set decoding bandwidth. Pin 8 is a transistor switch to ground. The pull up resistor to pin 4 leaves the pin “high” until decoder pulls it low. The 30k trimmer sets the the decode frequency, which can be read, using a frequency counter to pin 5. The 30k trimmer and 1500pf set the detection frequency.
Post Edited (bobledoux) : 4/5/2005 9:48:32 PM GMT