I noticed yesterday that long-time (but mostly inactive now) TI community member Ben Ryves published a video describing a project that uses an ESP8266 to connect calculators with old-style (not USB) link ports to the internet via wifi. Here's the source code, and that video:


The principle of operation is that the ESP8266 speaks the TI link protocol and treats it like a serial connection, then works like an AT modem. On the calculator, Telnet 83 Plus is all that's needed- although that program was designed for use with an old-school serial modem and a TI-Graph Link cable (the "Gray" link cable), it's pretty easy to do the protocol conversion that is normally done by the link cable in the modem firmware instead.

This is extremely cool stuff: I'm happy to see Ben continue to build new projects for graphing calculators. I recommend watching the video through: I was repeatedly surprised as he got deeper and deeper into what this makes possible (spoiler alert: for example, seamless, software-free WiFi file transfers between calculator and computer). People have been talking about WiFi for calculators for so long, and this is an elegant solution.

Amazing! Is there a way to make one for the TI-84 Plus CE?

Ben's work is always amazing and this is no exception.

Something similar could be made for the CE since you can connect to an ESP8266 as a USB serial device. More trickery would be involved to make the calculator think you're connected to a PC or other calculator for seamless file transfer however.

There aren't any ESPs that directly support USB, so it's a little harder than just hooking up USB- you'd need to either use a different chip that does support USB or possibly bit-bang a USB device controller in software.

Just doing the modem part probably wouldn't be too hard at least; you could swap out the TI link protocol parts for CommandBlockGuy's CDC library and use the USB-serial connection in the same way (basically just swapping out the TI serial link protocol bridge for a USB CDC bridge).

I should have clarified that I was referring to a board with an inbuilt USB->Serial interface (like a CH340) such as the Wemos boards: https://www.wemos.cc/en/latest/d1/d1_mini.html

Just re-reading you're talking about USB in general, which yeah would be more involved.

I see, yes; if you're willing to use a USB-serial bridge chip then the only work required is to make the calculator program speak USB CDC instead of the TI link protocol, though you'd sacrifice the "TI-connecting over the network" feature in that configuration. If you had a microcontroller that actually spoke USB it might be feasible to run DUSB over the network via USP/IP or similar, though I think you'd also need the micro to be the USB host to make that work exactly like a PC connection whereas the CDC mode requires the calculator to act as host.

I'm currently creating creating the same thing for the TI-84 Plus CE but at a crazy level of unreadable code lol