Small OLED modules look interchangeable at first glance, but mounting holes and the panel cutout needed for the display to show through rarely match between vendors. A clean panel installation usually means a precise display window plus four accurately placed screw holes. Those dimensions change from one module to the next.


Subtle differences in distances between displays from different manufacturers

This project packages a raw 0.96" I2C OLED with no intermediate processing module inside a 48×29 mm panel-mount enclosure with screw terminals. Build it only once across prototypes without resoldering or crimping custom cables.

Why?

Panel instruments in the 48×29 mm form factor share a practical semi-standard: one rectangular cutout, internal clips and a front bezel that hides imperfect edges. That idea was borrowed from low-cost DC panel meters, including the popular “9-in-1” voltage/current/power modules, which already use a two-board internal layout.


Panel-mount digital voltmeter

After searching for an off-the-shelf product that combined panel mounting, a dumb I2C display and robust screw terminals, nothing turned up at hobby quantities. The reference starting point was the popular “9-in-1” DC voltage/current/power panel meter in a 48×29 mm enclosure.

Inside the 9-in-1 meter


Inside the 9-in-1 meter


Inside the 9-in-1 meter

Core component: 0.96" OLED 128x64 bare screen I2C.

Panel-mount OLED module assembled in 48x29 mm enclosure

Key features

  • Open source hardware: KiCad sources and Gerbers on GitHub
  • Raw I2C OLED interface (no on-board MCU)
  • 48×29 mm panel-mount bezel tolerates a rough cutout
  • Six independent 0805 indicator LEDs with separate anode/cathode terminals
  • Double-level 3.5 mm screw terminals for solid wire, stranded wire or Dupont leads
  • Two-board stack: solder once, rewire many times across projects

Practical notes

At heart, the goal was simple: solder the display once, then move the module from one prototype to the next without touching the iron or crimper again. Screw the wires, unscrew them, done. If you rework cabling on the bench or inside an instrument box, that convenience adds up fast.

The electronics are the easy part; the enclosure is where the time goes. Empty 48×29 mm cases barely exist in hobby quantities. The realistic move is to buy the cheapest panel meter you can find and strip it. For the front window, everything was tried: the donor voltmeter’s red sheet dims the OLED too much, and green or blue pieces did no better. The grey translucent lens from the donor multimeter looked best (or dark translucent acrylic up to 1 mm if you cut your own).

One reassuring detail: the panel cutout does not need to be perfect. The bezel hides rough edges and internal clips hold the module without extra screws. Dupont plugs on the bottom terminal row are a snug fit (not the most comfortable row to work with), but once seated they stay put even if you tug the cable.

Component Datasheet - Buy link.

Optional components:


Electronic design

The design splits functionality across two boards joined by a 1×8 header. The display board carries the XC6206 3.3 V regulator, the OLED auto-reset network, I2C coupling, some capacitors used by the display's internal DC/DC converter and six indicator LEDs with independent terminals. The connector board only routes to the double-level screw terminals. Full schematics and design notes are in the GitHub repository.


Schematic (display and connector boards)

Assembly

Manual build follows the two-board layout seen in cheap “9-in-1” panel...

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