Older(?) Canon(?) DSLRs also used a 2.5mm jack to control the shutter release, so some people realized if you just spammed data into it from the TI-83 you could

Older(?) Canon(?) DSLRs also used a 2.5mm jack to control the shutter release, so some people realized if you just spammed data into it from the TI-83 you could trigger it. Add a crude BASIC script and you have an extremely basic timelapse setup.