Add Mycelium To Your Mesh Networks

October 26, 2021 by Bryan Cockfield 21 Comments

In many parts of the world, days after a good rainfall, it’s fairly common to see various species of mushrooms popping up out of the ground. These mysterious organisms aren’t the whole story, though. The living being is a vast network of hidden fibers, called mycelium, spreading through the ground and into any other organic material it can colonize. Its air of mystery and its vast reach are the inspiration for entire Star Trek shows and, of course, projects like this LoRa-based mesh network called Mycelium.

Mycelium is the invention of [Catamine] and includes many novel features compared to more typical mesh networks. For one, it is intended to be used in low power applications to give users the ability to send messages over a distributed network rather than a centralized network like a cell phone service provider. For another, the messages are able to be encrypted and authenticated, which is not currently possible with other mesh networks such as APRS. The idea is that a large network of people with nothing more complicated than an ESP32, an antenna, and this software would be able to communicate securely in situations where a centralized network is not available, whether that is from something like a natural disaster or from a governmental organization disabling the Internet during a political upheval.

The mesh network is currently in active development, and while messages can not yet be sent, the network is able to recognize nodes and maintain a keybase. There are certainly plenty of instances where something like this would be useful as we’ve seen before from other (non-encrypted) LoRa-based network solutions which are built around similar principles.

Thanks to [dearuserhron] for the tip!

Simple Electronic Hacks Inspire Doing More With Less

October 26, 2021 by Ryan Flowers 18 Comments

It’s late at night. The solder smoke keeps getting in your tired eyes, but your project is nearly done. The main circuit is powered by your 13.8 V bench supply, but part of the circuit needs 9 V. You dig into your stash to find your last LM7809 voltage regulator, but all you have is a bunch of LM7805’s. Are you done for the night? Not if you’ve watched [0033mer]’s Simple Electronic Circuit Hacks video! You know just what to do. The ground pin of a LM7805 connects to the cathode of a TL431 programmable Zener diode pulled from an old scrapped TV. The diode is referenced to a voltage divider, and voila! Your LM7805 is now putting out a steady 9 V.

How did [0033mer] become adept at doing more with less? As he explains in the video below, his primary source of parts in The Time Before The Internet was old TV’s that were beyond repair. Using N-Channel MOSFETs to switch AC, sensing temperature changes with signal diodes, and even replacing a 555 with a blinking LED are just a few of the hacks covered in the video below the break.

We especially appreciated the simple, to-the-point presentation that inspires us to keep on hacking in the truest sense: Doing more with less! If you enjoy a good diode hack like we do, you will likely appreciate learning Diode Basics by W2AEW, or a Diode Based Radiation Detector.

Thank you [DSM] for the tip! Be sure to submit your the cool things you come across to our Tips Line!

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There’s Not A Cassingle Thing Missing From This Cassette Deck Masterclass

October 26, 2021 by Kristina Panos 78 Comments

For [ke4mcl], this whole cassette craze of late is not a new discovery so much as it is a personal nostalgia machine. Since [ke4mcl] sees a lot of basic questions go unanswered, they made an incredible beginner’s guide to all things cassette deck. This concise wealth of information covers everything from terminology to operation, basic maintenance like repairing the belt and lubricating the motor, and appropriate cleaning methods for the various parts. Yep, we’re pretty sure this covers everything but the pencil winding technique, which you probably already knew about.

You don’t need a lot of tools and supplies to maintain a cassette deck or twelve (apparently they’re addictive) — mostly just head cleaning fluid, isopropyl, window cleaner, and a bunch of cotton swabs. And given this guide, you’ll enter the enclosure confidently, armed with knowledge about everything from the belts to the capstan to the head. This is valuable information, the kind of stuff your older brother wouldn’t take the time to explain to you in the 80s. But maybe he didn’t know reverse bias from the holes in the top of the tape.

Don’t care for the quality of audio cassettes? Tapes are good for lots of stuff, like data storage and decoration.

3D Printer Bed Probing Using A Tact Switch And Coin Cell

October 26, 2021 by Al Williams 39 Comments

Inspired by his CNC’s leveling system, [Chuck] built a small PCB to help level his 3D printer and he shares the details in the video you can see below. The idea is simple, the nozzle pushes down on the PCB which has a tact switch underneath. When the switch closes, an LED lights.

In practice, you measure the height of the board and use that for your Z offset, and you are done. Our only concern would be how repeatable the switch is. Granted, most people use a piece of paper and that’s probably not totally repeatable or accurate either. Proper feeler gauges are the “right” way to do it, but we know only a few people who do that.

If you ever look into the repeatability of various Z probes like the proximity sensors or the little pins that drop out of a 3D Touch probe, they aren’t that repeatable. Some people use microswitches, too, which is pretty similar to this approach and is apparently good enough.

The board is available, but it is simple enough that you could create it — or an equivalent — with just about any method you use for your PCBs. [Chuck’s] prototype board was milled. We are always surprised more people don’t use the nozzle itself to sense the bed. Some people go to a lot more trouble than just electrical contact even for CNC.

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SuperSlicer Reviewed: Another 3DP Slicer?

October 26, 2021 by Al Williams 32 Comments

When you think of slicers for FDM 3D printing — especially free slicers — you probably think of Cura, Slic3r, or PrusaSlicer. There are fans of MatterControl and many people pay for Simplify3D. However, there are quite a few other slicers out there including the one [TeachingTech] has switched to: SuperSlicer. You can see his video review, below.

Of course, just as PrusaSlicer is a fork of Slic3r, SuperSlicer is a fork of the Prusa software. According to the project’s home page, the slicer does everything Prusa does but adds custom calibration tests, ironing, better thin wall support, and several other features related to infill and top surfaces. The software runs on Windows, Linux, or Mac.

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How Much Is That Shirt In The (Atmospheric) Window?

October 26, 2021 by Kristina Panos 41 Comments

Summer is fading into a memory now, but as surely as the earth orbits the sun, those hot and sweaty days will return soon enough. And what can you do about it at the level of a single, suffering human being? After all, a person can only remove so much clothing to help cool off. Until someone figures out a way to make those stillsuits from Dune, we need an interim solution in which to drape ourselves.

We’ve seen the whitest paint possible for cooling buildings, and then we saw a newer, whiter and more award-winning paint a few months later. This paint works by the principle of passive cooling. Because of its color and composition, it reflects most light and absorbs some heat, which gets radiated away into the mid-infrared spectrum. It does this by slipping out Earth’s atmospheric window and into space. Now, a team based in China have applied the passive cooling principle to fabric. Continue reading “How Much Is That Shirt In The (Atmospheric) Window?” →

IoT flower pot monitors moisture and temperature levels.

Smart Flower Pot Build Is All About That Base

October 26, 2021 by Kristina Panos 10 Comments

For some reason, it seems like most of the plant monitoring setups we see separate the plant and the monitoring system. This makes sense in a don’t-own-a-waterbed-and-a-cat kind of way, but it also doesn’t from an aestheitc standpoint. This build by [Jorge Enrique Gamboa Fuentes] sure does look nice and tidy as an all-in-one unit, and fortunately is built with obvious issues in mind. It tracks water level, soil moisture, and soil temperature with a single device — a STEMMA-connected soil sensor that does all the monitoring work.

This attractive beginner build is a Python-powered project that runs on a PyPortal Titano and has a speaker that anthropomorphizes the thing so it can ~~berate you~~ politely ask for water in English. But the real magic of this build is in the enclosure itself. Thankfully, it’s designed with a drip tray, but it also keeps the electronics out of the water, allowing just the tip of the sensor to get wet. You can view the vital signs directly on the device, or on a web dashboard whenever you’re away.

In the future, [Jorge] wants to experiment with GCP and Azure, connect more flower pots together, and add more sensors so that it is more autonomous. One of the major lessons learned was that you probably shouldn’t start with a succulent, because they need very little water and this will drag out your development time considerably unless you over-water it, which will kill it. Check it out after the break.

If [Jorge] wanted to go the easy route, they might stick this plant under an old Keurig that’s been converted to an automatic watering device.

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