Arduino RMS Meter Module

This is a small Arduino module for measuring TrueRMS voltage. The meter displays the rms voltage in mV with digits and an analog level scale.

The module is intended as a "build in" module for monitoring a signal.

Step 1: Specifications and Parts

Specifications

• Bar-graph / Digital readout.
• Specifications: Vrms: 50mV -> 1000mV
• Freq: 20Hz – 20kHz
• Input Impedance: 50 kohm

Dimension: 30x30x30 mm – display frame 3D printed

Arduino sketch: 3794b / 46% - 141b / 28%

Main parts:

• ATtiny85 (DIL)
• TLE2071 (OpAmp)

Step 2: Circuit Diagram

The design is build with an input circuit for correct signal level for the Arduino.

This is designed by a virtual ground level of 2V5. This is needed for the analog input and correct signal measurement.

The op-amp also improve the input impedance. The overall gain is 0dB.

Step 3: Arduino Code

Comments

[Elaina M]

Thanks for sharing :)