David Knaack

Since I’m trying to use a PID controller to keep the chamber temperatures under control I need to tune the PID parameters. And since this is designed to run for hours at a time, and because I’m crap at PID tuning, getting it right it is very tedious. A…

The code I’ve been using to run the temperature controller for the crystal chamber so far has been pretty bare, just the core PID loop. I don’t have it tuned yet, but it’s generally functional, so it’s time to start getting it in shape to be an applian…

I cobbled together a simple temp controller to try to get a feel for what it’ll take to make one that will work for my temp controlled crystal-growing chamber. For this first iteration I’ve just got a simple PID-controlled heater, LM75 I2C temp sensor,…

For my crystal-growing I’d like to have better control over temperature so that I can cool solutions very slowly. I’ve been using a heavy ceramic dish and a hot water bath for this, but I want to try cooling rates of days or weeks. To achieve that I th…

Recently I’ve been playing around with growing crystals. It was always a fun and easy thing to do when I was a kid, so I thought I’d try some that are more interesting than the usual salt, sugar, alum, epsom, etc.This is recrystalized acetylsalicylic a…

A friend from the Omaha Maker Group gave me an interesting chip a while back. Apparently it is some kind of optically sensitive chip, it has a clear case.I thought it would be interesting to take some macro photos of it and see if I could capture some …

I was curious why a large aperture on a lens reduces depth of field. To investigate this I set my camera up with a macro extension tube and a subject with lots of depth.The subject is a potassium sodium tartrate (Rochelle salt) crystal mounted in a bra…