So I got him to solder on an ISP header and start drawing patterns on grids of graph paper while I got the toolchain working and updated some of the 2000’s-era code so it would compile.

Launch Microsoft Excel. Create a table with headings Binary and Hex, or use an existing one. Under the hex heading type =BIN2HEX (A2,5). A2 is the Binary number you want to convert.

Binary and hexadecimal numbers systems underpin the way modern computer systems work. Low-level interactions with hexadecimal (hex) and binary are uncommon in the world of Java programming, but ...