The Raspberry Pi 4 needs a fan, here's why and how you can add one

December 2020 Update: Lo and behold, the Pi Foundation tacitly acknowledges the Pi needs a fan in the official case, because now they sell the Case Fan!

The Raspberry Pi Foundation's Pi 4 announcement blog post touted the Pi 4 as providing "PC-like level of performance for most users". The Foundation even offers a Raspberry Pi 4 Desktop Kit.

The desktop kit includes the official Raspberry Pi 4 case, which is an enclosed plastic box with nothing in the way of ventilation.

Fixing the blurry focus on some Raspberry Pi Camera v2 models

The original Raspberry Pi Camera model v1.3 came from the factory set to ∞ (infinity) focus, so when you used it out of the box for something like a landscape timelapse rig, or for security or monitoring purposes (where the Pi is at least 5 meters away from the subjects it's recording), everything would look crisp and sharp.

For many fixed-focus cameras and lower-end camera sensors, it makes sense to set them to infinity focus; closer objects are still recognizable, but slightly blurry. Most of these cameras don't need to focus on a person a meter away for a portrait, and they're also rarely used for FaceTime-like video chat.

A good use for a Raspberry Pi - Missile Control

My brother gave me what will likely be one of the best useless-but-oh-so-fun gifts ever—a Dream Cheeky Thunder USB foam missile launcher.

Dream Cheeky Thunder Missile Launcher - USB

The launcher can be used with an extremely boorish app for Mac or Windows... or you can control it with some basic USB communication! I've found a few projects which allow the launcher to be controlled via any OS with Python fairly easily: