ESP32 internet modem with PPPD and secure Contiki webbrowser

I have been working on a internet modem for the ESP32 that can be used with a wide variety of computers, some more retro than others. Here are some expected use cases:

• Apple II without TCP/IP connects with a VT52 or VT100 terminal.
• Old Macintosh with TCP/IP stack, but no ethernet card, connects with PPP.

Basically, since the ESP32 is so cheap, it is much more affordable than a dedicated Raspberry Pi + interface card. One of the big issues is connecting to the modern web with SSL and complicated web pages. Although connecting to a computer running Lynx is certainly feasible, I was looking for something more lightweight. So, here is a sample of some of the applications:

Webbrowser

AT+WEB=<URL>

Above is a screen shot of Virtual ][ (an Apple II emulator) running DCOM 3.3 (a VT100 terminal emulator) connected the esp32 contiki webbrowser. This setup can be used to connect an Apple II to the internet.

And this is the same browser running in the Mac terminal. In the lower right, you can see the Mac has a terminal window that is connected to the ESP32 and showing a https secure web page. The HTML is parsed by the Contiki webbrowser, which I modified to use the ESP32 web client that includes SSL encryption. The ANSI/VT100 colors are added by my Contiki console i/o module that detects the VT terminal type.

PPPd

AT+PPPD

For computers with TCP/IP stacks, but no ethernet card, use the PPPD command, making a serial TCP/IP connection, so all your existing internet programs will work:

Telnet

AT+CIPSTART=<IP Address>

Of course, since it uses the standard ESP32 AT commands, you can do all the normal connections to telnet-based BBSs.

Some of the code is on my GitHub page, with more to come!