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SRF04 Ultrasonic Rangefinder
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A low cost ultrasonic rangefinder for measuring distances
between 3cm and 3m.
The SRF04 requires a short 10us pulse to the trigger
input to start ranging. The module then sends out an 8 cycle
burst of ultrasound at 40kHz and raises its echo line high.
It then listens for an echo, and as soon as it detects one
it lowers the echo line again. The echo line is therefore
a pulse whose width is proportional to the distance to the
object. By timing this pulse with your controller it is
possible to calculate the range.
Please note that unlike the
SRF10 and
SRF08 ultrasonic
rangefinders the SRF04 does not support I2C communications.
Examples of using the SRF04 module with a wide range
of popular controllers may be found
here.
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Technical Data
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| Voltage |
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5V |
| Current |
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30mA typical 50mA maximum |
| Frequency |
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40KHz |
| Range |
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3cm-3m |
| Sensitivity |
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Detects 3cm diameter broom handle
at > 2m |
| Input Trigger |
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10us minimum TTL level pulse |
| Echo Pulse |
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Positive TTL level signal, width
proportional to range |
| Dimensions |
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43mm x 20mm x 17mm height |
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SRF02 Rangefinder
