For racing games, flight simulators, and a few other simulation-style games, a simple controller just won’t do. You want something that looks and feels closer to the real thing. The major downsides to these more elaborate input methods is that they take up a large amount of space, requiring extra time for setup, and can be quite expensive as well. To solve both of these problems [Rahel zahir Ali] created a miniature steering wheel controller for some of his favorite games.

While there are some commercial offerings of small steering wheels integrated into an otherwise standard video game controller and a few 3D printed homebrew options, nothing really felt like a true substitute. The main design goal with this controller was to maintain the 900-degree rotation of a standard car steering wheel in a smaller size. It uses a 600P/R rotary encoder attached to a knob inside of a printed case, with two spring-loaded levers to act as a throttle and brake, as well as a standard joystick to adjust camera angle and four additional buttons. Everything is wired together with an Arduino Leonardo that sends the inputs along to the computer.

Now he’s ready to play some of his favorite games and includes some gameplay footage using this controller in the video linked below. If you’re racing vehicles other than cars and trucks, though, you might want a different type of controller for your games instead.

You’ve probably heard that a 3D printer is capable of producing its own replacement parts. Sometimes, that even includes upgraded or improved versions of the parts it was originally built with. But sometimes, it’s hard to figure out what improved really means. Think about air ducts that cool the part after printing. In theory, it should be easy to design a new duct. But how does it perform? Empirical testing can be difficult, but [Mike] shows how you can simulate the airflow so you can test design changes and validate assumptions before you print the actual part.

Of course, this wouldn’t only apply to printer ducts. You might also get some tips if you want to model airflow for PC cooling, hot air soldering, or other air-related projects. The free version of the software has some limitations, but it was surprisingly capable.

We also enjoyed how [Mike] used fluid to visualize the actual patterns and compared it to the simulation. The trick is using a compound from a kid’s science project kit, and it seems to work very well. Of course, you could just grab your smartphone. This might be worth thinking about if you are building a laser cutter air assist, too.

Before the age of lithium batteries, any project needing to carry its own power had to rely on batteries that were much less energy-dense and affordable. In many ways, we take modern lithium technology for granted, and can easily put massive batteries in our projects by the standards of just a few decades ago. While the affordability of lithium batteries has certainly decreased the amount of energy we need to put in to our projects to properly size batteries, there’s still a lot of work to be done if you’re working on a bigger project or just want to get the maximize the efficiency and effectiveness of your DIY battery pack.

The main problem with choosing a battery, as [ionworks] explains, is that batteries can’t be built for both high energy and high power, at least not without making major concessions for weight or cost. After diving in to all of the possible ways of customizing a battery, the battery guide jumps in to using PyBaMM to perform computational modeling of potential battery designs to hopefully avoid the cumbersome task of testing all of the possible ways of building a battery. With this tool virtually all of a battery’s characteristics can be simulated and potential problems with your setup can be uncovered before you chose (or start production of) a specific battery system.

While customizing a battery pack to this extent might not be a consideration for most of us unless the project is going to be big enough to run something like an electric car or a whole-house generator, it’s a worthwhile tool to know about as even smaller projects like ebikes can benefit from choosing the right cell for the application. Some of the nuances of battery pack design can be found in this guide to building packs from the standard 18650 cells.

Header: Lead holder, CC BY-SA 3.0 .