It is, of course, possible to realize such a circuit entirely using only discrete components, but in this article we will show you how you could build one using an Arduino and a multipurpose shield. Besides the LEDs there is also an LCD that operates as a VU meter and with a few pushbuttons it is easy to set the different thresholds.



This is an excellent project to gain some programming experience with an Arduino! This circuit demonstrates all kinds of things:
- Sound-level measurements with an Arduino
- Generating an alarm
- Digital filtering
- Driving an LCD
- Driving LEDs
- Reading switches
- Implementing a Setup menu
- Displaying a bar graph
- Using LCD custom characters
- Storing and then retrieving values from the EEPROM

Want to read more? Download the full article for free as a PDF file in the 'Attachment' section below.