pH measurement is a quirky and often frustrating technology. Usually working well, they can go wrong in so many ways. With dozens upon dozens of pH probes in service on the cultivation pads I have now spent a few years attempting to discover all of the ways a pH measurement can go bad.
pH Sim 2 in use checking a Symbrosia Controller
A voltage generated by ion exchange across a glass membrane is the magic that makes a pH probe work, simply measure the voltage and you can measure the hydrogen ion activity of a solution. The result is a number from 0 to 14, with numbers less than seven being acid, and numbers above seven being basic. Most aquatic or marine life, such as healthy algae require conditions close to 7, or neutral, too acid or too basic and everything dies.
I have owned this stereo microscope since I was a teenager. At first used for examining rocks and minerals in my collection, it has found many uses over the years, mostly used during assembly and inspection of various bits of electronic gear. It has been a workhorse microscope, well used, and well loved.
An American Optical model 40 stereo microscope
Despite this it bit me!
I know the feeling all too well, that little 60Hz nibble of 120Vac electrical power, a feeling anyone who has worked with electricity like I have recognizes instantly. Somewhere in this microscope 120Vac power is shorted to the frame.
After a couple years of use the Jeep Compass has been a fairly good vehicle. A decent daily driver, good gas mileage where gas is $5 a gallon, and able to do rough back roads with little worry.
A damaged cargo bed support in a Jeep Compass
I do have a few complaints, one of which had to be dealt with this week… The cargo area bed supports simply failed. I had noted signs of stressed plastic before, some cracks appearing after hauling heavy loads.
The final straw was Deep Violet, my 18″ telescope… Weighing in at well over 100lbs. When unloading the ‘scope after a night at Kaʻohe I found that the bed seems to have collapsed under the weight. The molded plastic bed supports simply ripped away from the cargo bed side panels.
An SUV where the cargo bed supports are two protrusions molded into the thin plastic side panels? Yeah, not impressed.
Building some small telescopes there are tools scattered across the workbench. Hex drivers are the most common tools on the bench to deal with the cap head socket screws I use for everything in my designs.
A rack for Bondhaus hex drivers
The hex drivers are supplied with a vinyl pouch. While a pouch may be a good solution for storing the tools, it is not a good solution for using the tools. I have to take out all of the drivers to find the one I want, invariably a small size buried under the bigger tools. The result is a scatter of tools across the bench and constantly trying to remember where I set down the one I need.
Sure, you can buy a nice little stand or rack, but they seem to be either cheaply made or expensive.
With a 3D printer available you see where this is going.
The design works very nicely, organizing the drivers where I can find them quickly and conveniently. Now to make a couple more racks for the small Wiha drivers I use for fine work and another for a set of larger screw drivers.
A 3D printed Bahtinov focusing mask for a Televue 76mm telescope
For this mask I used a public bit of OpenSCAD code from Jens Scheidtmann to generate the mask pattern, just tuning it for the correct sizing and performance with the TV-76. I added my own version of the support collar, making it a bit neater with fillets and properly sized to slip over the TV-76 glare shield.
The part is one of a half dozen parts I have designed and printed over the last few weeks to reassemble the photo rig. A new guide camera mount, a mount for the ASI Air computer, a new glare shield for the guider, etc., etc… The utility of 3D printing a game changer for me.
A couple weeks ago at the volcano I let quite a few folks take imagery of the lava using the afocal technique, simply holding the phone up to the eyepiece. This works rather well as the phone uses a lens much like the human eye, about the same aperture.
Shooting afocal with an iPhone and the TV-76mm ‘scope
The only real issue is holding a phone in just the right spot. Folks wanted video, but holding the phone steady is a real challenge. I had thought of making something to do this many times, last weekend I did it.
A session of playing around in 3D CAD resulting in a couple bits of clever plastic printed with the 3D printer… Done.
There are commercial solutions for this available, quite a few actually. But most of these are intended to adapt to a single phone, using some sort of clamping arrangement that you have to setup for a particular phone. I envisioned something that was more universal, quickly adapting to any phone.
The method I chose was a sliding magnetic platform that holds the phone. Just a simple shelf actually, set the phone on it and slide until you get it lined up. The base piece is printed with a recess into which a steel plate is set. The slider has three 8mm x 2mm neodymium magnets to securely grab the steel plate.
It took a bit of work to cut and file the steel plate to neatly fit the base, a bit of inlay work. Otherwise making the piece is quite easy. The only design issue is that this adapter is setup to fit a single eyepiece, a Televue Panoptic 27mm, and cannot be easily adapted to others.
The 3D CAD files are linked below. I have included the SCAD source file to allow tinkering with the design, possibly adapting to a different eyepiece. Both parts should be printed with support on, the pockets for the glued bits will have to be cleaned out, the resulting rough surfaces just right to recieve epoxy.
At the Keanakakoʻi Overlook I was able to test the adapter with a variety of different phones, both iPhone and Android, graciously lent to me for my experimentation. OK, the owners may have wanted a few lava photos. There was no difficulty using the adapter other than a moment or two needed to line up the camera with the exit pupil of the eyepiece. The result was more than a few smiles.
Continuing in my 3D printing bender I have been finishing up a few projects that have been on hold due to missing bits. A few other prints have been done to improve the printer itself. While along the way there have been a couple things designed and printed just for fun.
Minimalist 3D Printed Lamp
I needed a lamp to keep the 3D printer bed illuminated without leaving all of the garage lights on. This light would allowed me to keep an eye on long prints using one of the little Wyze security cameras.
A bright LED supplied by the 24V power supply of the printer would be just the thing.
I wanted a smaller, lighter finder ‘scope for the Astrola, and I wanted right angle to stop straining my neck!
3D model of the 40mm finder designed in OpenSCAD
I have been using a big Orion 9x60mm finder on the Astrola, the only telescopic finder ‘scope I have among the Telrads. It is nice, with a bright image that shows many faint fuzzies. It is also huge, and very heavy, it is also straight through, requiring one to crane your neck around to view through it on the Newtonian ‘scope.
The Creality Ender 6 is an impressive 3D printer, particularly for the price. It does exhibit some obvious design issues however. One of these is the hot end cable clamp, it is just not sized well. This critical cable harness flexes constantly as the hot end moves back and forth.
The Ender 6 hot end cable clamp as supplied
The supplied clamp is one of the few 3D printed parts on the Ender 6. As you can see from the photo the clamp is simply not large enough to properly secure the cable loom. This is odd, as it would have been so simple to design and print a properly designed part.
Can you leave the clamp like this? Some hackers do, I have seen several YouTube videos of well used Ender 6’s with the original cable clamp and loose wiring. It does work, I printed my first prints with the clamp like this. However, if left alone it is likely that the wires would be stressed over time leading to premature failure of the cabling and requiring an annoying repair effort.
