This is my hot water humidifier version b. It works better than the first attempt in that it does not get waterlogged then sink, due to the use of Styrofoam (vs packing foam in the first attempt) for the flotation function. There is also thin fiberglass top and bottom to avoid glue that did not work in hot water.

Fiberglass sheet is inexpensive, strong, and water-resistant. Working with it can be a pain, though, because fiberglass tends to quickly dull saw blades and drill bits. I have found that Black & Decker Very Thin Cutoff Disks work really well for cutting large holes in thin (.03") fiberglass sheet. That is the first photo.

For drilling holes, a 600-grit diamond attachment on the Dremel tool works as fast as a drill bit might. That is the second photo.

I needed to humidify the space where I grow mushrooms. This is a low-budget, fuss-free humidifier. Unlike commercial humidifiers, it does not require purified water. It works by heating water relative to the environment. Power can be controlled by plugging the cord into a variac or other transformer.

The plywood circle did not have sufficient buoyancy, so I glued some foam on top. The slot in the stainless tube accommodates the appendage on the cup heater to make it stay put.

This is my slow-speed drill press. it works well for drilling large holes in soft materials and for making gaskets. Directions for making such abound on the 'net, but I just ordered belts and sheaves that I thought would work from McMaster-Carr. If I were to do this over again, I would start with a heftier drill press, and I would use timing belts/sheaves instead of v-belts. Timing belts don't need as much tension to avoid slippage.

There are hurdles to Psychotria viridis cultivation in the southwest American desert: Occasionally freezing weather is one of them. I designed and constructed a soil heater. Materials: fiberglass tubing from Max Gain Systems, RT-12, OD .5", ID .25". Also nichrome wire, 26 gauge at 2.6 ohms/foot. I pushed the wire into teflon 22 gauge teflon tubing before inserting it into the fiberglass tubing. Total resistance is 122 ohms = 108 watts for 115 VAC power.

I needed to create a roof for my shroom fruiting box to provide fresh air and blue light. All LED strips are 12V, and go to one end of a Kobiconn 163-4021 panel connector. The wood was too thick for that connector, so I reduced the thickness with a 13/16 forstner bit. The other photo shows the 12V fans, wired to a CUI PJ-202AH connector which I had to mount to a small piece of fiberglass, which is then mounted on little standoffs. The same CUI PP3-002A plug will mate to both connectors.

I created a strong table because the old card table was not strong enough for the new shroom fruiting box that features a 5 gallon water reservoir (more on that, later). I used mending plates for most of the fastening:

homedepot.com/p/Simpson-Strong

Prototyping surface mount hardware is intimidating at best. This guy featured on Hackaday has been there, done that. I really like his modified exacto tool for scratching copper from PCBs. And check the comments here, also. Expertise is everywhere you look.

hackaday.com/2020/05/24/ironcl

Here is an open-source lab-grade scale, made via 3D printing and run on an arduino.

mdpi.com/2410-390X/4/3/18/htm

Two photos: One is a set of breaking fixtures, as I like to call them. I created them for the purpose of strength testing my new glass-based material. The older, smaller breaking fixture is at top, followed by the larger, later fixture. Below that is a bar of my new material. Below that is a mold for casting such bars. I cover the mold with aluminum tape to increase moisture retention. The second photo is the breaking fixture in action. The force sensor is FC2211-0000-0025-L from Mouser.

I added a couple pieces of wood to raise to work level to where the particle-free breeze is blowing.

I am delighted with the HEPA air source performance for sterile transfers. I was able to transfer mycelium from petri dish to syringe to culturing jars without contamination. I was also able to pour agar from a flask into petri dishes without any contamination. This perfect outcome was not possible using my still air box.

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I have struggled with using a still-air box (plus bleach spray, gloves, and sleeves) for sterile work with spotty success. So I decided to obtain a HEPA air source. Sticker shock → build my own.
I used a hammock filter as a pre-filter.That way, it could be big, minimizing back-pressure. Here is the HEPA air source half finished.
I used hardware cloth (coarse galvanized screen) held in place by wood chips and Weldwood contact adhesive to hold the cut hammock filter in place.

I decided to replace the old under-the-cabinet fluorescent lamp (hasn't worked in years) with an adhesive-backed LED strip (warm white from Ebay - $7.50 for 5 meters). I got a 12V switching power supply wall wart ($8.00 from Ebay), removed it from the case, and stuck it a wood box (held together with 5-minute epoxy). The box is stuck to the cabinet wood with Weldwood contact cement. The little brackets that help the LED strip stay up are made from 1/16" UHMW.

One can also program a WiFi module from TI using micropython.

The WiPy is a small, ultra-low power and low cost Wi-Fi module
targeted to the Internet of Things.

e2e.ti.com/blogs_/b/connecting

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Many makers balk at the prospect of learning C. I can't blame them. Even with extensive comments, C programs written by others can be difficult to wrap one's head around.

Micropython is a maker-friendly option that may work well depending on one's choice of microcontroller.

designnews.com/electronics-tes

@jmwright One more thing about free-hand SM circuit construction: solder paste (and, of course, a really good soldering station) is a must for such small connections. It can be pricey, it needs to be kept in the 'fridge, and it has an expiration date. I got my little syringe tube maybe 4 years ago. Long-expired, it still works well for hand soldering.

I have long had a few ideas that could only be implemented on an FPGA. I only have experience with microcontrollers: a whole different world. I tried to learn Verilog and relevant tool chain. I asked a question on the main Verilog forum (it's been a long time - I forgot which), the main guru there snapped "you need to learn the basics first". I thought I had. Needless to say, I was discouraged. Now I see that some progress is being made on this:

digikey.com/en/articles/techzo

My little, but useful, fungus scraper is shown to the left of a petri dish of fungus that could be scraped. This is a sturdier version of the inoculation loop that microbiologists use.

I cut a strip of stainless, shaped it, stuck it into a stainless tube, forced in a little brazing paste (sra-solder.com/soldering-brazi), then torched it. For this little job, a propane torch might have been sufficient.

Brazing is a useful skill. Nobody showed me. I watched videos, bought stuff, then made mistakes.

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