A decibel meter is a device which measures sound pressure to determine how intense sounds are, measuring in decibels. Decibels are a logarithmic scale based on the sensitivity of the human ear.
A pedometer it’s a device that calculates the distance that a person has walked or run the steps you take, then converts those steps into distance by knowing the length of the person’s stride. Using this device can be an effective way to motivate an individual into doing more walking.
A speedometer is vehicle device that measures and displays the speed, and is essential for safety purpose on roads and highways.