# two bars, one tiny screen.

A small Flipper Zero side quest: putting Codex usage limits on a dedicated display.

Author: Vlad Kostoglodov. Language: en.
Archive date: 2026-05-13. Current version prepared: 2026-10-14.
Date basis: Date of the original Telegram post and photo.
Status: ready.
[Profile and technical work JSON](https://vk0st.com/facts.json): public profile, concrete work and source references.
[Human-readable article](https://vk0st.com/writing/flipper-codex-monitor/).

I made a small project called [Flipper Codex Monitor](https://github.com/vk0st/flipper-codex-monitor). The premise fits on its intended screen: two bars for Codex usage limits, with labels showing when they reset.

Putting two percentages on a separate piece of hardware is a fairly elaborate way to look at two percentages. That is part of the charm.

On May 13, 2026, I posted a photo in my Telegram blog with a short caption: “Found a new use for the Flipper.” This was that use.

![A Flipper Zero resting on a keyboard, with 5H and 1W usage bars on its orange screen.](https://vk0st.com/media/flipper-limits.webp)

From my blog, May 13, 2026. The values belong to the photo.

## A small job for each side

The [display](https://github.com/vk0st/flipper-codex-monitor#readme) covers the five-hour and weekly usage windows. A Rust backend on the computer reads the limits through the local Codex CLI app-server, formats reset times in the computer's timezone, and sends a compact packet to the Flipper over Bluetooth Low Energy.

The packet is **21 bytes**: percentages, reset labels, and a status byte. The Flipper does not need to parse JSON or work out timezones.

![An outlined handheld screen with two progress bars connects to a desktop computer through a small packet arc.](https://vk0st.com/media/articles/flipper-codex-monitor-v2.webp)

The computer prepares the packet; the little screen only needs to display it.

The [backend](https://github.com/vk0st/flipper-codex-monitor/tree/main/backend#readme) keeps the app-server process alive and is designed to transmit once per second. Most of the machinery lives on the computer; the Flipper's job is to draw two bars.

## Some inherited plumbing

This project builds on TheSainEyereg's [Flipper PC Monitor app](https://github.com/TheSainEyereg/flipper-pc-monitor) and [Rust backend](https://github.com/TheSainEyereg/flipper-pc-monitor-backend), with Willy-JL's BLE serial helper. The little monitor already had useful plumbing; I gave it a different thing to monitor.

The Codex version has a narrower job: account-limit information, with credentials staying on the computer. The [roadmap](https://github.com/vk0st/flipper-codex-monitor/blob/main/ROADMAP.md) keeps the same focus. It lists reconnect reliability, easier installation, and more tests among the next steps.

For now: two bars on an orange screen. The Flipper has a new job.