Story
Admin Pocket Toolkit Offline
Overview
Admin Pocket Toolkit Offline transforms the Elecrow ESP32 Miner LCD into a portable toolkit for system administrators, DevOps engineers, cloud engineers, and IT professionals.
The device was originally designed as a standalone Bitcoin miner, but thanks to the flexibility of the ESP32 platform, I repurposed it into a completely different product: a handheld offline utility that provides everyday administration tools without requiring a laptop or an Internet connection.
Unlike web-based calculators, this version runs entirely on the ESP32 microcontroller and is optimized for the 2.8-inch touchscreen display. It is based on the Elecrow ESP32 Miner LCD development board, which features an ESP32 processor, touchscreen, Wi-Fi, Bluetooth, SD card support and is fully compatible with Arduino IDE, PlatformIO and LVGL.
Why I built it
As a DevOps and Cloud Engineer, I often need quick access to tools such as:
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CIDR Calculator
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chmod Calculator
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Cron Expression Generator
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Unix Timestamp Converter
Most available solutions require opening a browser or using an online service.
I wanted something that:
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fits in a pocket,
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starts instantly,
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works completely offline,
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protects sensitive information,
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can be carried anywhere.
This project demonstrates that inexpensive ESP32 hardware can become a practical productivity device rather than being limited to its original purpose.
How it works
The firmware is written in C++ using Arduino Framework and PlatformIO.
The graphical interface is built with LVGL and optimized for the 2.8-inch touchscreen.
Every calculation is performed locally on the ESP32.
No cloud services.
No backend.
No user accounts.
No telemetry.
No Internet connection is required.
Current Features
✔ CIDR Calculator
✔ chmod Calculator
✔ Cron Expression Generator
✔ Unix Timestamp Converter
More tools are planned in future releases.
How to build the project
Step 1
Flash the firmware onto the Elecrow ESP32 Miner LCD board.
Step 2
Connect the device using the USB-C cable.
Step 3
The application starts automatically after boot.
Step 4
Navigate between tools using the touchscreen interface.
Step 5
Perform calculations locally without any network connectivity.
Demonstration Video
Or watch on YouTube:
https://www.youtube.com/watch?v=lrTHDVkG1Hk
Project Article
A complete walkthrough, architecture overview and source code explanation are available on my blog:
https://lepczynski.it/en/other/pocket-admin-toolkit-a-practical-admin-tool-built-on-esp32/
Source Code
GitHub Repository:
https://github.com/lepczynski-cloud/crowpanel-Admin-Pocket-Toolkit
Future Plans
The project is still evolving. Planned features include:
- a cron expression helper,
- a Unix timestamp converter,
- a cheat sheet for the most frequently used Docker commands,
- a cheat sheet for Git commands,
- a list of Linux signals and process exit codes,
- most frequently used DNS records,
- ...
The long-term goal is to build a practical open-source pocket toolkit that every system administrator can carry in their backpack instead of relying on online tools.
