When you want to see the stars, find someplace dark
It is always a sick feeling in the gut when a drone goes down.
This time it was an unseen branch, a thin and leafless thing that reached well out from the tree, unseen until it was too late. Unseen by the drone’s obstacle avoidance system as well.
I crashed the drone at Panther Falls while enjoying a waterfall day in Southern Washington. A place deep in the trees where a drone pilot is advised to exercise caution. I did, and crashed it anyway.
Continue reading “Crashed and Repaired”
Designing and building equipment for aquaculture means I use controllers. Quite a few controllers, dozens upon dozens of them, little boxes meant to keep some parameter in range. Temperature, pH, water level, whatever, a little box with a display, a few buttons, and a relay in the back to turn something on when needed to control the outcome.
Industrial suppliers will sell you a controller for just about anything, there are catalogs full of them, from inexpensive to thousands of dollars you can buy the solution to your needs. Buy one, wire it in, adjust a few setpoints and you have everything under control.
Enter the STC-1000, a little cheap temperature controller found on eBay, Amazon, everywhere. It comes in a bunch of different versions, need readout in Farenheight or Centigrade? No problem. I have no idea who makes it, some asian factory somewhere. It is available in a hundred different brand names from hundreds of different sellers for somewhere between $12 and $25, all absolutely identical as far I as can tell.
The STC-1000 is cheap. Cheap enough that I am somewhat suspect of their reliability. I do not buy them for production line bioreactors and grow tanks, places where I cannot trust a cheap controller with a few thousand dollars worth of product. For critical uses I buy full industrial rated temperature controllers from a reputable supplier for around $100 each.
But for experimental setups? Temporary research hacks built with more limited budgets? There are a couple dozen of these STC-1000 controllers around the place. They are easy to use with simple configurations, seem to be accurate holding calibration, and I have not had one fail yet.
So how do you sell a device like this for about $15?
Time for a little deconstructive analysis…
Continue reading “What is safe?”
For all of the many times I have done it, I have never gotten tired of typing a command, or clicking a button on a screen, and watching something happen in the real world.
An LED turning on, the click of a relay, or even a motor beginning to spin… These represent a moment when the seemingly ethereal digital realm of our computers interact with the physical domain.
I have spent my entire career dealing in the interface between the ethereal and the physical, working where the two meet. Turning sensor readings into digital, and then turning the digital into actions in the everyday world. I played with this interface as a teenager, learning the basics. My wisely chosen college degree was tailored to this task, an electrical engineering degree with a heavy dose of computer science. Professionally I have dealt with microcontrollers, high performance analog to digital systems, and programmable logic controllers, all straddling the boundary line from digital to physical.
Continue reading “Betwixt the Realms”It has become apparent to me that what were modern electronics in my youth are now considered vintage electronics. What does that say about me?
The piece of vintage electronics in question this day is a veteran Tektronix 465 oscilloscope. This particular oscilloscope was purchased decades ago as surplus from Elliot Electronics in Tucson, once my go to place for electronic parts and tools.
The ‘scope is in great shape… Mostly.
Continue reading “3D Printed Fix… Again”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.
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.
Continue reading “An Open Source pH Probe Simulator”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.
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.
Continue reading “LED Microscope Lights”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.
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.
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.
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.
Continue reading “I Am Not Impressed Jeep”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?
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.
Continue reading “A Century in Service”