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Brainstorming and an Anecdote

A project log for Thingamajig from Stuff

Starting a project with no real direction, and finding it along the way.

williamdelnickiwilliam.delnicki 02/03/2015 at 11:411 Comment

Brainstorming:

Basically an under-powered laptop that's been cut in half and had crap stuck to the backside. The idea was much more majestic in my head, but I just shot this down as I thought of how to describe it. And now that I think about the rest of the brainstorm, it was all based on that one half thought idea. What a super duper update to the log!

Instead I'll give you some insight into who I am. Of course instead of giving you the insight outright ... you can try and gather it yourself from the convoluted mess I have written below.

TL;DR-- Used CD drives as sketchy computer thermal control relay for fans running on mains power, and ordered a part for a project that isn't even this one. Continue reading if you want a lot of semi-relevant back-story and detail.

So I ordered a lens enclosure for a laser diode from a DVD burner. It was funny, do you ever have those moments where you get onto something, an idea or a new word, and then all of a sudden you encounter it somewhere else? I was looking into servo control for the RPi and came across laser etchers using old DVD drives. I have so many DVD drives on hand from salvage that don't work or are just outdated (IDE) and I just don't have the heart to send them to be recycled so I thought it would be perfect. I spent a few hours researching and thought it was a go, so I ordered some components that I can't scavenge easily. The very next day HaD features a project of just that very thing. Anyway, this is neither here nor there and isn't even the anecdote. It is however relevant, as I thought I'd share a little project that I did a few years ago.

It was dead simple and very effective. In my basement I have a Smirnoff Ice cooler from a convenience store. It stopped working because apparently it got a leak in the refrigerant system. Bad news for the environment, but it did make it easier for me to cut the compressor and condenser etc. out. So I thought it'd make a good server rack. The nature of a cooler is to keep temperature in which is bad when it's heat generated by electronics, so I had to come up with a way to ventilate. I took the top part of the sealing gasket off the door (handy as I could run my wires through that gap) and cut a hole in the side for a 120mm aluminum fan that I got from an ancient server rack that was donated to the tech department of my high school to play around with. There were two fans, one mounted on the side near the bottom, the other was just sitting on a rack on the inside in the middle pointed up at the bottom of the electronics and towards the opening at the top.

The fans were quite interesting as they run on 120VAC; two were wired into a little box that was merely an enclosure to house where it was spliced directly into a connector the same as on a computer's PSU. The only problem with the fans was that they sounded like a gang of pissed of air-hockey tables coming to beat you up. So since my basement is relatively cool, and the components I planned on putting in the 'rack' didn't generate a tremendous amount of heat I thought I could just do a thermostatic control on the fans. Wow, I'm only just now getting to this part of the story? So anyway, I figured the best way to accomplish this using the materials I had was this:

I took two CD drives, and gutted one of them. Then I rigged them so that the working unit opened into the (nearly) empty case of the other. After some creative mounting involving hook-eyes and screws through the suspended plastic trays, I spliced a power cable (read: extension cord) and had it so that when the CD drive opened, the screw on the end made contact with the hook-eye completing the circuit which powered the fans. It was like a very unsafe version of a computer controlled 120V relay. Then all I had to do was use a program call nircmd by Nirsoft and another program that I can't find right now (I almost think it was related to CPU-Z) which would execute commands based on certain parameters such as CPU temperature. So when the temperature got up high enough, I had it run a batch file I made that would give the nircmd command to open the drive to turn the fans on. Then it would wait 500 seconds, close the drive to turn the fans off, and then exit ready for the next cycle. This worked very well for quite awhile, until I tore it apart because I really didn't have a need for a server rack at that point.

Discussions

PointyOintment wrote 02/04/2015 at 00:02 point

"It was funny, do you ever have those moments where you get onto something, an idea or a new word, and then all of a sudden you encounter it somewhere else?"

That's known as the frequency illusion or (more commonly on reddit) the Baader-Meinhof effect.

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