Learn more about how we select deals. TL;DR: The forever-useful Texas Instruments TI-84 Plus graphing calculator is on sale for $88 at Walmart, saving you $28. Since the dawn of time (okay ...

mostly involving builds that turn graphing calculators like the TI-84 Plus shown above into something that copies a few features from a smartphone. His latest build, a hardware GPS module attached ...

[Owen] got down and dirty by adding a touchscreen to his TI-84 graphing calculator. The dirty part is the z80 assembly code he wrote to use the linkport as a UART (assembly always makes us feel ...