---
title: "CardRepeater"
url: "https://ankush.one/projects/2025.cardrepeater/"
description: "Firmware that turns an M5Stack Cardputer into a pocket WiFi repeater, with a retro green terminal UI and a web setup page."
author: "Ankush Singh"
date: 2025-10-24
lastmod: 2026-10-12
tags: ["hardware"]
repository: "https://github.com/ankushKun/cardputer-wifi-repeater"
links:
  - {"archived":false,"label":"GitHub","url":"https://github.com/ankushKun/cardputer-wifi-repeater"}
  - {"archived":false,"label":"Download firmware","url":"https://github.com/ankushKun/cardputer-wifi-repeater/releases/tag/0.1.0"}
---

# CardRepeater

Links:

- [GitHub](https://github.com/ankushKun/cardputer-wifi-repeater)
- [Download firmware](https://github.com/ankushKun/cardputer-wifi-repeater/releases/tag/0.1.0)

**CardRepeater turns an M5Stack Cardputer into a WiFi repeater you can keep in your pocket.**

The Cardputer joins your WiFi and puts up its own access point at the same time, then routes traffic between the two with NAT, so anything that connects to it gets online through it. The little screen shows a CRT-green terminal with the uplink signal strength, how many devices are connected and whether the internet actually works (it pings to check, because being on WiFi doesn't always mean being online).

Setup happens from your phone: join the open `CardRepeater` network, open 192.168.4.1, then type in the network to repeat and a name and password for the repeater's own network. I went with a web page because I couldn't get the built-in keyboard working 🙃

## Features
- Station and access point at the same time, with NAPT and DNS forwarding
- Internet check with a green, yellow or red indicator
- Live uplink RSSI and client count on the display
- Web setup page at 192.168.4.1
- Prebuilt firmware on the GitHub release

## Built With
- M5Stack Cardputer (ESP32-S3)
- PlatformIO and ESP-IDF
- C++