Digital or Analog 4/17/23

Thoughts with Richard Bleil

Apparently, I am a lifelong learner. I mentioned in a recent post that I am doing a project (available for purchase) designed to teach students about circuitry and programming. Because of my background, I know about both individually, but have never put them together before.

Now, I’m kind of old-school. Yesterday, I warmed up some bread sticks in my toaster oven. They were supposed to cook at 400 degrees for ten minutes. So, I set the oven accordingly, but this oven is unusual for this day and age. See, the dials are analog, as is the built-in timer. You may well remember these timers, where as you spin it there is a distinct sound like a very rapid clicking, and as the timer runs there’s a familiar “tick-tock” sound. This is an analogue device.

No doubt, you can buy toaster ovens that are digital, but I’ve never seen the point of making things digital when analogue works just fine, and has for decades. Yes, you can get a pretty little screen and type in the temperature and time, but I don’t see the point when I can just as easily (and perhaps more easily) turn the dials.

In my first project, we basically made a circuit that I made in elementary school. I know I wrote about this already, where you run current through a Light Emitting Diode (LED) and you get light. In my elementary school project, it was an incandescent lamp, and it had more control than was available in this project, since I included a variable resistor allowing me to brighten or dim the light as desired, rather than simply turning it on or off. My elementary school project was analogue, but this project was digital which means that I needed to create a feedback loop with the controller board and write a code to turn the light on or off.

To be fair, though, the purpose of this kit is education. Yes, I know enough circuitry to have been able to build my own light, and I know enough programming so that I could have figured out how to write the program. But in putting them together, I started learning about controller boards from this very first and simple project. For example, I didn’t realize that they had both analogue and digital inputs, and programmable outputs. To turn the light on or off, basically I told it which output pin to turn on (supply five volts to) or off (change to zero volts). Despite the fact that I could have easily made this circuit better in analogue, I still learned quite a bit with the kit.

I still believe, and always will, that as a society we are moving too many things to digital that work just fine in analogue. My washer and drier are digital, but they work no better, and have no more control, than I used to have in washers and driers built in the 1970’s with analogue dials. But, I’m beginning to see why one might sometimes choose to convert to digital circuits.

In a later day, we built a little circuit that was more complicated. Instead of one light, we built a circuit with three lights. This circuit also included switches for each light, which, again, would be easily accomplished with an analogue circuit. The circuit seemed overly complicated, because when the switch was on, power was provided to the controller circuit that then, through programming, instructed the controller board to turn that particular LED on. It would have been much easier just to supply power directly to the light when the switch was on, but then we did something that I could not have done with the analogue circuit.

Through the programming, once the controller board was told to light the LED, I could then program how to turn on the LED. For example, I had one LED permanently on (when the switch was on), programmed another to blink continuously (like a beacon) and the third blink the SOS Morse code continuously. Here I began to see why I might want to make this a digital, rather than analogue, circuit. To blink a message like SOS through an analogue circuit, I would need a switch that I could continuously turn on and off. With the digital circuit, I could just loop it continuously until the switch was turned off. What’s more, if I wanted to change the message, or the LED sending this signal, it can be easily done through programming rather than requiring a re-wiring.

It seems as if, in our world, there is room for both digital and analogue circuits. If I wanted to disappear from the grid, I would buy a car built in the ‘70’s to eliminate the possibility of computer chips and the ways that it can be tracked. But having a chip monitor fuel mix, engine temperature, and so forth and making adjustments to maximize power or efficiency also makes sense. Those old engines are just fine, but the settings are tuned for an average running condition, losing efficiency at low and high temperatures. In the meantime, I’m going to keep learning.


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