The number module displays information about the signal it’s receiving from your other modules. It has two modes: in “value” mode, it displays a number from 0 to 99 on its LED display, where 0 is totally off, and 99 is all the way on. In “volts” mode, it displays the actual voltage on the signal pin, from 0.0 to 5.0 volts. It takes the same signal it receives and sends it out to the next module.
The number module measures the voltage present on its input connector, then displays that value in one of two modes. In “values” mode, it displays the percent of full scale from 0 to 99, with 5V being full scale, or 99. In “volts” mode, the module displays the voltage at the input.
UNDER THE HOOD
The input signal is buffered by an opamp (U1), then passed through a single pole RC low pass filter to band limit the signal to around 16Hz. This signal is passed to the Analog-to-Digital Converter (ADC) of an Atmel ATMEGA168 microcontroller (U2). The microcontroller performs digital domain noise reduction, and converts the measured ADC values into display values. These values are translated by the microcontroller firmware into control signals that illuminate the correct segments of the display to represent the desired numbers.