Comments by "ke6gwf - Ben Blackburn" (@ke6gwf) on "Technology Connextras"
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The thumb hole on the Coleman pump is actually genius. It's simply so that the pump stays retracted when you aren't using it.
The pump rod is hollow, meaning that the space in front of the plunger is vented through that hole, so no pressure can build up in the pump cylinder unless you cover the hole.
If you cover the hole then the pump works as if it had a solid rod and no hole in the piston, but as soon as you take your thumb off it vents any pressure, and the plunger sits retracted.
It also vents any pressure that might escape from the check valve leading to the tank, otherwise a slight leak would cause the damage to pump to push all the way out.
The pump itself is normal, just a cup seal (originally leather, later rubber), so on the up stroke it lets air past the seal into the pump chamber, and then inflates and seals on the down stroke.
So there is no truth to needing to take your thumb off on the up stroke.
It's also why you need to occasionally put a drop of oil in it, to keep the leather soft and lubricate the bore.
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One thing to realize is that different brains function differently. When I look at an analog clock, I have to count ticks to read the time. Some people can glance at it and know the time, but my brain has never functioned that way.
So for me, a digital clock makes more sense, because it says the exact thing that I have to reverse engineer from an analog clock, thus saving me the time and effort.
It's like the difference between writing out an equation, and simply stating the results.
How would you rate this video on a scale of 1 to 3+2+4+1?
(insert some algebra formula in here that I can't come up with off the top of my head!)
I guess I have always dealt with exact time. My dad taught me 24 hour time, but I was rebellious and became bilingual.
Then I started in ham radio as a teenager, then working with satellite TV uplink and downlink, and then worked at a radio station where I kept all the automation system clocks set correctly, so I have always needed perfectly accurate clocks and watches, used to call Time every day, or tune in to WWV, and was very happy when this new thing called the Internet started allowing automatic time setting!
I know that some people think in "half past the hour", or "10 til 5", but I have to parse those meanings into hour:30 and 4:50.
I internally think in 12 hour format, but can transpose to and from 24 hour format instantly, since I have used it so much.
Sometimes I think in 24 if I am trying to math something, otherwise I use my fingers lol
So for me, I have little love for analog clocks, though for certain applications where movement of time is important, rather than exact time, it's useful.
Similarly, I want a vehicle tachometer to be analog so I can see the sweep and rate of change compared to red line or shift points, but I need a digital speed readout since generally the only thing I need that number for is comparing it to the sign on the side of the road (now, the sign on the Maps display lol).
In my truck, I actually mounted an old smartphone to the dash and have a GPS speedometer app running on it, so whenever I start the engine it opens the app, and I have a digital speed display. I only use the analog speedometer occasionally if I am wanting to see rate of acceleration.
On the other hand, on something that is constant speed, such as the motor on an industrial device where I am setting the RPM and leaving it, I want digital, because I want that exact number, rather than a needle in the general vicinity.
The Inverter Variable Frequency Drives for electric motors don't have dials, they have digital readouts because they put the motor at an exact speed.
With some equipment, I will add a needle or histogram display in addition to the digital number, so that speed changes can be tracked visually as well, but that's only useful if it's changing speeds frequently.
So basically analog is good to display change and rate of change, but digital is best for accurate data and not having to parse a picture to get a number.
And you know the fancy clocks that only have the 4 primary numbers, or no numbers at all, just some lines? I hate those! I literally have to count lines and try to estimate the number of degrees in between to get an accurate reading, because I don't function with the approximate.
I remember in my EMT class, the instructor saying not to record a blood pressure as anything other than a line on the gauge that had a number by it. If it wasn't specifically marked, and you tried to estimate it, you were making it up. So you read to the nearest Number and wrote that down.
This is pretty much the entire point of reading an analog clock, Making Stuff Up! Lol
Now, when taking blood pressures or counting respirations, having a sweep second hand was amazing since you could visually watch for 15 or 30 seconds while counting, without having to parse anything, simply watching for the hand to get to a particular location, but I could do the same thing by watching the seconds on my digital watch, it was only slightly harder.
But most of the interaction I have ever had with time, digital made so much more sense, since that's the form it got converted to in my head anyway.
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