And once again, I'm reminded that summers in southern California can get really, really hot. Sitting in the heat trying to comprehend details of ROS gets very tiresome very quickly. Normal house fans can't cut it anymore. Air conditioning is an obvious solution, but it racks up my electric bill. But in the relatively dry climate of California, there is another option: the evaporative cooler ("swamp cooler").

I could buy one, but a local maker tried the DIY option and that looked like it might be interesting. The key find enabling such an experiment is a cooler pad designed for the purpose and available for just $5.

https://www.instagram.com/p/BmKLSXpA66b/?utm_source=ig_web_copy_link&igshid=6tlxxilut9ft

My first attempt was to put that pad inside an old 10-gallon pail already in the house and just collecting dust. Unfortunately, the plastic for the pail proved too brittle to withstand drilling. Whether it is from old age or if the compound is fundamentally brittle I can't tell, and the actual reason doesn't matter anyway.

Brittle pail

Plan B: Use a cheap Home Depot 5-gallon bucket. Using rulers to measure out spacing, ventilation holes were drilled in the bucket. It was tedious but surprisingly took less time than I had feared.

Holey Bucket

Once holes were drilled, the pad was placed inside the bucket along with some water. A cheap pump designed for decorative water fountains were placed inside along with some hoses to circulate water, keeping the cooling pad damp.

For air circulation: I first tried to adapt my house fan but it proved too unwieldy. Moving on to plan B, I used a computer cooling fan salvaged from a dead ATX power supply. It bolted directly to the bucket lid and, with aid of a simple 3D-printed adapter to a flexible dryer duct, its output air can be directed to where it does the most good. Here's my cooler, next to its inspiration.

https://www.instagram.com/p/BmcUcHLAjw2/?utm_source=ig_web_copy_link&igshid=j4frb8k5ihbk

The output air stream feels a lot cooler than ambient air, so the project is an overall success. But there is room for improvement...