Years ago I bought myself an IR remote for my Nikon D40. That worked ok, but of course I wanted to build my own using a Digispark.
There’s lots of tutorials for IR remotes out there, like LuckyLarry’s. I then later came across the nikonIrControl library which basically allows you to trigger a photo with a single line of code! Best of it is this library will work for every camera supported by ML-L1 and ML-L3 such as D40, D40X, D50, D60, D70, D70s, D80, D90, D7000, D5000, D5100, D3000, Coolpix 8400, 8800, P6000, P7000, P7100, Nikon 1 J1/V1.
And because the intervalometer should be as tiny as possible I was using a Digispark to control everything.