You're welcome. I did a write-up from some time ago: https://mcturra2000.wordpress.com/2019/09/03/brown-noise-sle... AFAIK the schematic is accurate. Use the bottom one because I do like the filtering. White noise tends to be too harsh for my liking. Although it is one of my earlier projects, it has proved to be a good and enduring solution (to me, anyway).

It has since acquired a snazzier encasement using balsa wood. I bought some wire mesh for the front of the speaker, to give it protection.

If you want to do day/night timing (although I personally think that's overkill) , you could think about adding a DS3231 clock. I recommend steering clear of those really cheap Chinese modules (DS1307, if memory serves). They're a complete waste of time.

Have fun!