Category Archives: Technology

Things humans make that weren’t there before.

The Awesome Task of Recoating a Telescope Mirror

If you enjoy pretty pictures of the universe, you owe it to yourself to learn how a common bit of maintenance is done on ESO’s VLT, or Very Large Telescope.

At some point, the reflector used in the VLT is beyond recovery, and they need to strip it of its mirror finish and recoat it.  This seems like it would be straightforward, but some of the most impressive robotics, machinery, engineering, and minds are applied to this task.  If anyone involved in the process is having a bad day, and they break the ceramic mirror base, the telescope would be out of commission for years until a replacement mirror is built.

I’ve worked on multiple critical systems in my career, but I’ve never seen anything quite like this.

Additional Treadmilldesk Criterion

Before I purchased the treadmill for my treadmill desk, I thought my criteria would yield good results.  For the most part, this is true; I’ve been using my treadmill desk for well over a year without issue.

Recently, my treadmilldesk’s treadmill started making some grinding noises that corresponded to the belt speed.  Technology never heals itself, so I opened up the workings to take a look.  After the usual dust cleaning, I isolated the source of the noise.  An important piece of plastic had warped from heat.

The speed sensor consists of a tiny piece of circuitry that counts how often some teeth pass through it.  The teeth are on a wheel attached to the main treadmill motor.  The sensor is on a plastic housing that sits directly on the metal motor.  Guess what happens as the motor heats up?  Yes, the sensor housing softens and sags, leading to a condition where the teeth rub against the housing as they move.

Under the “normal” usage scenario, which consists of someone buying the treadmill, using it for a week, then putting plants on it until they sell it used, this piece of plastic would never distort.  However, if you actually intend to use your treadmill as a treadmilldesk, as I do, walking at 2.5MPH for 3-8 hours a day, you might want to consider getting a higher-end model that will last.

I will fix the sensor mount problem somehow, but when this treadmill finally does fail, the next one I get will be designed for long-term use.

Car Disaster Avoided

As we continue to make software a component of more technologies, software failures are evolving from losing the last 20 minutes of your work to losing the rest of your life.  I was recently reminded of something that happened to me years ago, in which I encountered a potentially life-threatening software failure.

In the winter, about 10 years ago, I had a major software failure in my 1997 Saturn SC2.  I was living near the top of a steep hill, with a road to match.  My drive to work required me to descend this steep road, which hit a low point before rising up again to touch the main road.  If you could look at the road from its side, it would resemble a check mark, with my house near the top of the longer stroke.  Now picture the road covered with a fresh, wet, slippery snow.

I descended the hill in low gear, to take advantage of engine braking, but I also had my foot on the brake.  The action of the ABS brakes caused the usual pulsation in the brake pedal, along with the typical rattling sound, as it kept my speed down.  So far, so good.  Then, after a few seconds of constant ABS activity, I lost the brakes, as my dashboard lit up with red lights.

“Hmm,” I thought.  The low gear was helping to slow me down, but it could only do so much without brakes.  My steering still worked, so my plan was to drift down the hill and rely on the braking power of the incline between me and the main road.  This was the plan for several seconds, until someone pulled onto the road from an adjacent apartment complex.  They were heading to the main road, too, and they were in front of me.

“Hmm,” I thought again.  I couldn’t rely on the other car moving fast enough to not be in my way, so I had to come up with a plan B.  I quickly thought about the failure, running through various scenarios.  While I wasn’t certain, I suspected that I had encountered a software failure, and that the hardware (the brakes and the ABS controller) were fine.  Ultimately, I decided to reboot the car.

This was a little scary.  Power steering would go away while I did this, even if only for a few seconds.  I’d also never started my car while the wheels were in motion.  Out of an obscure memory, I pulled information my dad told me once: “You can start a car with automatic transmission in either Park or Neutral.”  Park was out of the question, but Neutral would work just fine.  So, I turned the key into the Off position, shifted to Neutral, and then turned the car back on.  After the usual brief test period for indicator lights, all the red lights were gone.  The brakes had resumed their clicking noise, and this time, they kept working.  After shifting into low gear, everything was back to where I wanted it to be.

I considered contacting Saturn about this, but I didn’t think it would lead to any improvements.  My mindset at the time was that unless I had a way to consistently cause this failure, the report wouldn’t be acted upon.  In fact, I only encountered that failure once during the time I owned the car.  If it happened to me now, I think I would contact Saturn and anyone else who had an interest in making sure cars are safe to drive.

If there’s any life lesson here, it’s that the Hitchhiker’s Guide to the Galaxy was right: Don’t panic!