All Things are Hard and Easy

It‘s funny how most things are both harder and easier than assumed. Take for example my 3D Printer: 3D Printing Resin changes its viscosity with the ambient temperature. For great results, a stable temperature of over 25°C is essential. So I set out to build a small enclosure heater to keep 30°C.

Harder than expected!

Turns out, the logic behind keeping a stable temperature is more complicated than expected. Let me give you the setup first. The heater consists of a few basic elements: a power supply, a fan, the heater itself, a temperature probe, and a tiny computer. In our abstraction, we‘ll only care about the heater, probe and computer for now:

$heater: receives a binary state ON or OFF. will produce heat when set to ON, and continue radiating heat for a certain time after turning OFF. has no awareness of ambient temperature.
$probe: knows the ambient temperature & reports it
$computer: receives the expected target temperature, knows the current ambient temperature, can send a binary ON or OFF to $heater

So what‘s the problem?, you might ask. Just send ON if ambient temperature < expected temperature, and else send OFF. (This is called a bang-bang controller, by the way.)

Unfortunately, since heating takes time, and the heater continues radiating heat after expecting an OFF temperature, the temperature will constantly fluctuate above and below the target temperature.

Screenshot of a temperature fluctuating graph using bang-bang control

Oh… This looks like some crazy advanced math will be needed!

Easier than expected!

Fear not: The beautiful and terrifying thing about living on a giant floating rock in space with 8 billion fellow humans (and carrying the legacy of roughly 100 billion humans who lived before us is that we are not as unique as we think we are. Whatever the problem souring our day today, we face overwhelming odds that our problem is not unique either. Even better, somebody probably had solved it somewhere and sometime!

In our case, the solution is called PID Tuning, and it can be used for all kinds of cool things that don‘t involve 3D printers or temperatures at all.

I won’t go into the details here, as this has been explained far better than I ever could by people smarter than me.

Screenshot of a temperature fluctuating graph using PID tuning

To Summarize

Most things have far deeper reaching implications and intricacies than one would initially assume.
Most problems can be solved, and many of them have already been solved by others.