ugh, that arduino-attiny link is giving a cloudflare error (I don't think I will ever recommend cloudflare since they use their front end position to blame you for hogging resources).
Here is the wayback version
https://web.archive.org/web/20131222...as-an-arduino/
Added flashing logic, on for 1/4 second, off for 1/4 sec.
Edit, oops, forgot the meter wants 0-1v not 0-5v... will fix later.
edit, fixed, divided val by 10 instead of 2