How to Add a Simple Digital Panel Meter

Several manufacturers have made it easy and inexpensive to monitor project power or other attributes without having to do much more than find a good viewing location and connect a few leads. Among the ready-made panel meters available are those that display current, voltage, frequency, power, temperature, resistance, pressure, or combinations of these meters.

Digital panel meters are available in LED or LCD configurations with a wide array of text colors and backlighting if needed. They may be fully enclosed with bezels or bare modules that attach with screws.

For an example of a simple application, a basic, two-wire voltage meter module is added to a claw machine gantry system to monitor voltage drop across a brush-based power transfer mechanism. The low-profile meter fits neatly inside a 3D printed motor mount and is connected to the gantry rails via the wire leads.

Some voltage meters utilize a three-wire system where the power supply is isolated from the voltage being monitored, which allows for zero or very low voltage measurement. In this example, it is expected the voltage will not drop below 20 V, so a two-wire meter fits the bill. The meter starts registering voltage when enough power is supplied to operate the meter’s circuitry. As an added feature, many panel meters, like the one used here, allow for calibration. A calibrated power supply set to a desired value may be used to calibrate the panel meter prior to permanent installation.

The smaller, less expensive modules with Test Clips installed on the leads make a handy temporary meter that takes up very little space in the work area. Cover the bottom side of the meters’ PCB to prevent unwanted shortages. Tinning the leads allows them to be pushed into breadboards for monitoring projects during the build. Conveniently, the mounting holes can be staked down using wire jumpers.

Whether a permanent or temporary installation, DigiKey carries a wide range of Digital Panel Meters that may be used in many ways to augment a project or provide diagnostics during the build.