Invariably when we write about living on Mars, some ask why not go to the Moon instead? It’s much closer and has a generous selection of minerals. But its lack of an atmosphere adds to or exacerbates the problems we’d experience on Mars. Here, therefore, is a fun thought experiment about that age-old dream of living on the Moon.
Inhabiting Lava Tubes
The Moon has even less radiation protection than Mars, having practically no atmosphere. The lack of atmosphere also means that more micrometeorites make it to ground level. One way to handle these issues is to bury structures under meters of lunar regolith — loose soil. Another is to build the structures in lava tubes.
A lava tube is a tunnel created by lava. As the lava flows, the outer crust cools, forming a tube for more lava to flow through. After the lava has been exhausted, a tunnel is left behind. Visual evidence on the Moon can be a long bulge, sometimes punctuated by holes where the roof has collapsed, as is shown here of a lava tube northwest from Gruithuisen crater. If the tube is far enough underground, there may be no visible bulge, just a large circular hole in the ground. Some tubes are known to be more than 300 meters (980 feet) in diameter.
Lava tubes as much as 40 meters (130 feet) underground can also provide thermal stability with a temperature of around -20°C (-4°F). Having this stable, relatively warm temperature makes building structures and equipment easier. A single lunar day is on average 29.5 Earth days long, meaning that we’ll get around 2 weeks with sunlight followed by 2 weeks without. During those times the average temperatures on the surface at the equator range from 106°C (224°F) to -183°C (-298°F), which makes it difficult to find materials to withstand that range for those lengths of time.
For many of us. the holiday season is coming up and that means hosting parties and mixing drinks, which can get tiresome. [GreatScott] has come up with a solution, what he calls a crude cocktail mixing machine. But don’t be fooled — it may look crude on the surface, and vibrate a bit while working, but the mechanism is plenty sound and functional.
The machine can mix three different liquids and does so using three peristaltic pumps. In typical [GreatScott] style, while he tears apart the pumps to replace the tubes, he gives us a good glimpse of just how they work. Using a knob and LCD screen, you can enter any quantity you want for the three liquids, though you’ll have to edit the Arduino code if you want to change the liquids’ names.
How does the machine know when to stop pumping a certain liquid? Each pump is rated for a specific quantity per second, though he tests this for each liquid anyway and finds a slight variation which he accounts for in the code. After the machine turns a pump on, a load cell located under the glass tells it when liquid has started arriving at the glass. A simple calculation based on the pump’s quantity per second and the desired quantity tells it how long to leave the pump on for. When the times up, it stops the pump. The result is a machine that’s sure to be a centerpiece for any hacker-filled party. Check out his build and the pump in action in the video below.
When the average person looks at a bed, they think about sleeping. Because that’s what beds are for. You cover them with soft, warm cloths and fluffy pillows and you sleep on them. [Peter] is not your average person. He’s a maker. And when he looks at a bed, he thinks about giving it the ability to track his weight.
The IKEA bed has four Chinese-made TS-606 load cells under each foot with custom aluminum enclosures. Each one goes to an HX711 analog-to-digital converter, which offers a 24 bit resolution. These feed an Arduino Nano which in turns connects to a Raspberry Pi via USB to UART bridge. Connecting to the Pi allows [Peter] to get the data onto his home network, where he plots the data to gnuplot.
This smart bed doesn’t just track [Peter’s] weight. It can also track the weight of other people in the house, including his pets. Be sure to check his GitHub for full source code.