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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16x2 Serial LCD
