The NXT Sound Sensor block gets data from the NXT Sound Sensor. You can measure the sound level as a percentage (0-100) and get a Numeric output. You can also compare the sound level to a Threshold Value to get a Logic (True or False) output.

See Using the NXT Sound Sensor for more information about what the NXT Sound Sensor does, the data that it provides, and programming examples.

Choose the Sensor Port and Mode

Port Selector

Mode Selector

Inputs

Outputs

Use the Port Selector on the top of the block to make sure that the sensor port number (1, 2, 3, or 4) matches the port on the EV3 Brick that the NXT Sound Sensor is connected to.

Use the Mode Selector to select the mode for the block. The Inputs and Outputs available will change depending on the mode.

Measure Modes

The Measure – dB and Measure - dBa modes each output the sound level in the Sound Level output. In the Measure – dBa mode, the sound level is filtered to approximate the sensitivity of the human ear over different frequencies.

The sound level is measured as a percentage (0-100). If the sound sensor has been calibrated, the sound level value is adjusted so that 0 corresponds to the minimum calibrated sound level and 100 corresponds to the maximum calibrated sound level.

See programming example 2 in Using the NXT Sound Sensor.

Compare Modes

The Compare – dB and Compare - dBa modes each measure the sound level as in the Measure modes. The Compare modes then compare the sound level to the Threshold Value using the selected Compare Type. The True/False result is output in Compare Result, and the sound level is output in Sound Level.

Calibrate Modes

The Calibrate modes allow you to calibrate the NXT Sound Sensor from within a program.

The Calibrate – Minimum mode allows you to specify the minimum sound level in the Value input. After calibration, the NXT Sound Sensor will report this sound level as 0 or the specified value.

The Calibrate – Maximum mode allows you to specify the maximum sound level in the Value input. After calibration, the NXT Sound Sensor will report this sound level as 100 or the specified value.

The Calibrate – Reset mode restores the NXT Sound Sensor calibration to its default state.

Inputs and Outputs

The inputs available for the NXT Sound Sensor block will depend on the mode selected. You can enter the input values directly into the block. Alternatively, the input values can be supplied by Data Wires from the outputs of other Programming Blocks.

Input	Type	Allowed Values	Notes
Compare Type	Numeric	0 - 5	0: = (Equal to) 1: ≠ (Not Equal to) 2: > (Greater than) 3: ≥ (Greater than or Equal to) 4: < (Less than) 5: ≤ (Less than or Equal to)
Threshold Value	Numeric	Any number	Value to compare sensor data to
Value	Numeric	0 – 100	Sound level for Calibrate modes

The outputs available will depend on the mode selected. To use an output, use a Data Wire to connect it to another Programming Block.

Output	Type	Notes
Sound Level	Numeric	Sound intensity (volume), 0-100.
Compare Result	Logic	True/False result of a Compare mode.

NXT Sound Sensor Block