Growing up in Montana I remember looking out at night and seeing the Milky Way, reminding me of my insignificance in the universe. Now that I live in a city, such introspection is no longer easy, and like 1/2 of humanity that also lives in urban areas, I must rely on satellites to provide the imagery. Yet satellites are part of the problem. Light pollution has been getting worse for decades, and with the recent steady stream of satellite launches and billionaire joyrides we have a relatively new addition to the sources of interference. So how bad is it, and how much worse will it get?
Looking up at the night sky, you can usually tell the difference between various man-made objects. Planes go fairly slowly across the sky, and you can sometimes see them blinking green and red. Meteors are fast and difficult to see. Geostationary satellites don’t appear to move at all because they are orbiting at the same rate as earth’s rotation, while other orbit types will zip by.
SpaceX has committed to reducing satellite brightness, and some observations have confirmed that new models are a full magnitude darker, right at the threshold of naked-eye observation. Unfortunately, it’s only a step in the right direction, and not enough to satisfy astronomers, who aren’t looking up at the night sky with their naked eyes, naturally.
The satellites aren’t giving off the light themselves. They are merely reflecting the light from the sun back to the earth, exactly the same way the moon is. Thus something that is directly in the shadow of the Earth will not reflect any light, but near the horizon the reflection from the satellites can be significant. It’s not practical to only focus our observatories in the narrow area that is the Earth’s shadow during the night, so we must look closer to the horizon and capture the reflections of the satellites. Continue reading “Things Are Looking Brighter! But Not The Stars”→
Most projects around here involve some sort of electronics, and some sort of box to put them in. The same is true of pretty much all commercially available electronic products as well.
Despite that, selecting an enclosure is far from a solved problem. For simple electronics it’s entirely possible to spend more time getting the case just right than working on the circuit itself. But most of the time we need to avoid getting bogged down in what exactly will house our hardware.
The array of options available for your housing is vast, and while many people default to a 3D printer, there are frequently better choices. I’ve been around the block on this issue countless times and wanted to share the options as I see them, and help you decide which is right for you. Let’s talk about enclosures!
Particle physics is a field of extremes. Scales always have 10really big number associated. Some results from the Large Hadron Collider Beauty (LHCb) experiment have recently been reported that are statistically significant, and they may have profound implications for the Standard Model, but it might also just be a numbers anomaly, and we won’t get to find out for a while. Let’s dive into the basics of quantum particles, in case your elementary school education is a little rusty.
It all starts when one particle loves another particle very much and they are attracted to each other, but then things move too fast, and all of a sudden they’re going in circles in opposite directions, and then they break up catastrophically…
It’s not infrequent that we see the combination of moisture sensors and water pumps to automate plant maintenance. Each one has a unique take on the idea, though, and solves problems in ways that could be useful for other applications as well. [Emiliano Valencia] approached the project with a few notable technologies worth gleaning, and did a nice writeup of his “Autonomous Solar Powered Irrigation Monitoring Station” (named Steve Waters as less of a mouthful).
Of particular interest was [Emiliano]’s solution for 3D printing a threaded rod; lay it flat and shave off the top and bottom. You didn’t need the whole thread anyway, did you? Despite the relatively limited number of GPIO pins on the ESP8266, the station has three analog sensors via an ADS1115 ADC to I2C, a BME280 for temperature, pressure, and humidity (also on the I2C bus), and two MOSFETs for controlling valves. For power, a solar cell on top of the enclosure charges an 18650 cell. Communication over wireless goes to Thingspeak, where a nice dashboard displays everything you could want. The whole idea of the Stevenson Screen is clever as well, and while this one is 3D printed, it seems any kind of stacking container could be modified to serve the same purpose and achieve any size by stacking more units. We’re skeptical about bugs getting in the electronics, though.
We’re all too familiar with the 3D printing post-processing step of removing supports, and lamenting the waste of plastic on yet another dwindling reel of filament. When the material is expensive NinjaFlex or exotic bio-printers, printing support is downright painful. A group at USC has come up with a novel way of significantly reducing the amount of material that’s 3D printed by raising portions of the bed over time, and it makes us wonder why a simpler version isn’t done regularly.
In the USC version, the bed has a bunch of square flat metal pieces, with a metal tube underneath each. The length of the tube determines the eventual height of that square. Before the print is made, the bed is prepared by inserting the appropriate length tubes in the correct squares. Then, during the print, a single motor pushes a platform up, and based on the height of the pin, that portion of the bed raises appropriately, then stops at the right height.
This is a significant savings over having a matrix of linear motors or servos to control each square, at the cost of having to prepare the pins for each print.
But it has us wondering; since CURA and other slicing software have the ability to pause at height, what if the slicing software could allow for the placement of spacer blocks of a known size? The user would have a variety of reusable spacer blocks, and position them in the software, and the slicer would build the support material starting on top of the block. It could print a rectangle on the base layer to aid in proper placement of the blocks during printing, and pause at the correct heights to let the user insert the blocks. At the end of the print a lot less support material has been used.
For situations where you want to leave your print to run unattended, or if the cost of the material is low enough that it doesn’t justify the effort, then maybe this isn’t worth it. Another problem might be heating that platform, though since only support material will be printed on it, some curling won’t matter much. What do you think?
We are accustomed to medical devices being expensive, but sometimes the costs seem to far exceed reasonable expectations. At its most simplistic, a hearing aid should just be a battery, microphone, amplifier, and speaker, all wrapped in an enclosure, right? These kinds of parts can be had for a few dimes, so why do modern hearing aids cost thousands of dollars, and why can’t they seem to go down in price?
The rest of the media were reporting on an asteroid named 16 Psyche last month worth $10 quintillion. Oddly enough they reported in July 2019 and again in February 2018 that the same asteroid was worth $700 quintillion, so it seems the space rock market is similar to cryptocurrency in its wild speculation. Those numbers are ridiculous, but it had us thinking about the economies of space transportation, and what atoms are worth based on where they are. Let’s break down how gravity wells, distance, and arbitrage work to figure out how much of this $10-$700 quintillion we can leverage for ourselves.
The value assigned to everything has to do with where a thing is, AND how much someone needs that thing to be somewhere else. If they need it in a different place, someone must pay for the transportation of it.
In international (and interplanetary) trade, this is where Incoterms come in. These are the terms used to describe who pays for and has responsibility for the goods between where they are and where they need to be. In this case, all those materials are sitting on an asteroid, and someone has to pay for all the transport and insurance and duties. Note that on the asteroid these materials need to be mined and refined as well; they’re not just sitting in a box on some space dock. On the other end of the spectrum, order something from Amazon and it’s Amazon that takes care of everything until it’s dropped on your doorstep. The buyer is paying for shipping either way; it’s just a matter of whether that cost is built into the price or handled separately. Another important term is arbitrage, which is the practice of taking a thing from one market and selling it in a different market at a higher price. In this case the two markets are Earth and space.