An evil WiFi Access Point for your pocket - because
Code is based on the original here: https://github.com/adamff1/ESP8266-Captive-Portal, with some tweaks to work with a display.
Here is the specific board the code is based on. If you choose to use a different board, you'll need to use the relevant settings and library for that display: https://www.aliexpress.com/item/1005004513260449.html
There are some instructions included on setting up the board and U8g2 library within the Arduino IDE. Unfortunately, I couldn't find this version without the pin headers, so you'll need to desolder/cut them to fit inside the case.
case you can 3d print for it here: https://www.thingiverse.com/thing:6099890
Once running, if you connect to the free wifi from a pc (probably easier than your phone) you can browse to the web server on http://172.0.0.1/creds to view all the saved credentials or to http://172.0.0.1/ssid to change the ssid. The credentials are written to the eeprom so will persist if the device loses power.
