DIY F-stop timer

I found this one on the internet:

http://www.henpe.se/cms/darkroom/articles/12-fstop

Is anyone familiar with this design or maybe build it?
It has just what I need and intent to built it one of these days.
It is basic but enough for my needs at the moment

I found the Brody design also but it looks not so user friendly, has more options however.

Hans, Henpe is an APUG member. Check out his thread:
(there was a url link here which no longer exists)

Oké, I din't know

Thanks for pointing me to the thread.