An Open Source pH Probe Simulator

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
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.

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LED Microscope Lights

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
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.

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Favorite Tools

For someone who works with their hands tools are important. We all have our favorite tools, that one we always use as we have for so many years. There may be a dozen screwdrivers in the rack, but that one is used almost every time.

A veteran Weller WES50 soldering station
A veteran Weller WES50 soldering station

Thus is with great sadness that I announce the death of my longtime soldering station.

A good soldering iron is a basic tool for an electronics engineer. A multimeter, a soldering iron, and a set of basic hand tools are absolutely necessary for any electronics workbench. To this end I had bought a very good iron, one that has served me well for several decades.

I wonder just how many soldered connections I made with this old soldering iron… Thousands upon thousands certianly, so many circuit boards, connectors, and wires.

There are no available spare parts for this long obsolete soldering station. There are many conversations on bulletin boards and chat rooms lamenting this as others have had their beloved soldering irons fail. The WES50 was long ago replaced by the WES51, and the parts are not interchangable.

With sadness I remove the old soldering station from the bench. I replace it with a new Weller WE1010NA station. I wonder just what work awaits the new soldering iron, how many solder joints will it see in the coming decades. I hope that this new iron will outlast me.

I Am Not Impressed Jeep

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
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.

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A Century in Service

In this age of short product lifecycles and rapid obsolescence it is nice to see an example of longevity. We consider equipment or tools old when over ten years in service. How about a century?

A compressed gas cylinder with inspection dates spanning over a cetury
A compressed gas cylinder with inspection dates spanning over a century

Our CO₂ is delivered in standard industrial pressure cylinders. These steel cylinders hold 50lbs of liquid CO₂ at a pressure sufficient to keep it liquid at room temperature, about or about 800PSI.

These standard cylinders require inspection every five years, and the inspection date is stamped into the steel at the top of the cylinder in the format month-year with a two digit year. It has been this way for a long time, longer than I realized.

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A Tool Rack

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
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.

If you like what you see you can download the design at my place on Cults3D.

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.

Yeah, I can make that.

Looking at the catalog I look at a price that is just too high. A few bits of molded plastic for almost a hundred dollars? You are kidding? Right?

A Fan Grill for $93??
A Fan Grill for $93??

Well? I need this. Actually I need a few of them.

This is when my frugal nature hits hard… I can make that.

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Battery Corrosion Again

Leaking alkaline batteries, the bane of our portable, battery powered existence. All too many times I have found myself repairing electronic devices damage by leaking batteries, or just junking the gear when the damage is too severe.

Corrosion damage in the base section of a Celestron 8SE mount
Corrosion damage in the base section of a Celestron 8SE mount

This time the device in question was just a bit too valuable to dispose of despite fairly extensive damage.

A Celestron Nexstar 8SE telescope.

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A Bahtinov Mask for the TeleVue 76

For some reason I have gotten along without a focus mask for the TV-76. Need to fix that… Done.

A 3D printed Bahtinov focusing mask for a Televue 76mm telescope
A 3D printed Bahtinov focusing mask for a Televue 76mm telescope

Just a quick project, about half an hour to design and four hours printing. First print a pleasing success, a completely functional part.

A Bahtinov Mask is used to get a precise focus, something I wrote about a few years back.

A 3D printed Bahtinov focusing mask for a Televue 76mm telescope
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.

You can download the SLT file for the mask from Cults3D if you need to print your own.

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.

Electrical Hazard

Over the last week at work we have been preparing an unused part of the facility for use. We need a place for an industrial freeze dryer and a walk in cooler. But first we had to clear out a massive pile of junk that had accumulated, and do demolition on a lot of old equipment and piping to remodel the space.

A burned and melted power receptacle
A burned and melted power receptacle

Demolition? Break out the sawzall! We used a big sawzall, a small pile of saw blades, an angle grinder with a diamond cutoff wheel, a bit of muscle and a lot of sweat to get it done. The pile of trash accumulated rapidly along the fence, old lumber, a lot of PVC pipe, and a lot of rust… A big dumpster will appear later.

Rust. This close to the ocean everything is badly corroded, do not even try to release the old bolts, just pop a fresh battery into the angle grinder and let the sparks fly. The 20 amp sawzall does not use batteries, good for the thicker pipes and framed walls, it rips through PVC like butter.

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