Tuesday, November 8, 2011

My First Minion

min·ion  [min-yuh n]   -noun
a servile follower or subordinate of a person in power.
Everyone wants power and minions, whether they know it or not. This has been true for a very long time. It has caused many problems throughout history when taken too far. Luckily, there are better options today.

My first minion was a rescue. Once, he had served a purpose and had a home, but now he was all but abandoned in a pile of semi-obsolete parts in a dimly-lit back room. (I do not know the actual lighting condition of the room in which he was stored, but I feel this description sets the proper mood for the story.) A good friend of mine, whom we shall refer to as Chris, recognized his potential and entrusted him to my care, knowing I would find a use for him.

I named him Blue.

Blue is a simple thing. Outdated, but still useful. Originally he was part of a control system in a water plant where his job was probably to open/close a valve and report back the valve position. He has digital inputs and outputs and an event timer which can come in handy. He communicates with a computer with ASCII commands, through a serial connection. (I said he was a bit dated..)

It took me quite a while before I came up with a project that needed him. It wasn't until I started home brewing beer. I decided to build a stir plate to help with one of the steps for growing healthy yeast. It was giving me some trouble, and I needed a tachometer, a way to measure RPM, to troubleshoot the stir plate. More on that later...

I set up Blue with a breadboard, standard power connection for use with an old computer power supply, RS-485 to RS-232 serial converter, and serial to USB converter. I then spent several frustrating days trying to talk to him.

Unbeknownst to me, someone had rewired the RS-485 to RS-232 converter. My best guess is that they had an overall installation that was wired backward, so the easiest fix was to cut traces on the circuit board, and jumper things around. They had swapped the two data pins. (Thanks, Chris...) After frustrating days working with outdated software, I opened the case and discovered this. A few minutes with a soldering iron, and he finally started responding.

With this small success and the minor project that followed, I was hooked. I would definitely need more minions.


  1. The back room is dimly lit, FYI.

  2. A quick stop at circuit city may have landed you a not so outdated tachometer. Of course it would not have been as fun. And yes, more on this beer.

  3. Circuit City? I think I'd have to work out the whole time travel thing first...

  4. I am curious. What was the minor project you tasked Blue with? How did he perform?

  5. That will be a future post. Stay tuned. (Or even better, subscribe!)

    I am sidetracked right now with fixing my phone touchscreen, but after that I will jump back to some electronics projects.