Friday, February 1, 2013

We've moved!

Hey all, I just wanted to send out an update that this blog has moved to a new address.  I have created a website for this venture, Ohmbrew Automations, and I am now hosting these posts as well as any new posts at the new location.

Here is the address to the new location:

Thanks to everyone that has visited this site. Hopefully the new one will be everything you've ever hoped for in a blog!


Sunday, June 24, 2012

A couple pics...

Everyone likes to get dressed up from time to time... but enough about what I'm wearing right now...  Here are a couple more pictures.

It was my first attempt at this style of picture.  I need to retake these with a little more light next time, but I'm still pretty happy with them.

Sunday, June 17, 2012

Video Demo

This here is what the kids call a motion picture.  I hear it's all the rave out west...  It's just a fad in my opinion.  But I'll cater to your whims....


Wednesday, May 16, 2012

Where has the time gone?

Ahhh springtime, when the bleak dreary doldrums of winter are transformed due to an astronomical combination of the revolution of the earth around the sun and a slight tilt in the rotational axis of the earth in comparison to the elliptical plane of the sun.  This scientific "magic" creates a season that leads to the emergence of life as well as an inversely proportional availability of time. Springtime begets green begets yard work begets baseball (OK, the last one is a bit of a reach, but baseball is, in fact, dependent upon the former).  The last two of which make up a considerable portion of my springtime, uh, time.

OK, so that's neat and all, but essentially, I'm just using it as a way to create a diversion from the fact (excuse) that I haven't been all that productive of late.  I have actually had quite a bit of progress made since the time that I have last spoken here, but when compared to the time lapse, I'm going to call this an "unproductive" period.

Despite all of this, I finally have a product that I'm willing to pawn off as a completed prototype.  I got everything put together the other night and closed the case up.  So at least it isn't naked anymore.
It still needs more testing and working a few bugs out here and there, but for the most part, it is at least presentable.

It took quite a bit of time to get everything placed in the box like I wanted it to.  The case definitely needs to be bigger to get everything I want crammed in there.  Routing the power wires inside the box was quite tedious.

As far as software changes, I added a feature to store and restore the current phase of the fermentation program to/from EEPROM (non-volatile memory).  This allows the thermostat to automatically restore itself to it's previous settings in the case of a power outage or brown-out.

I also re-wrote all of the code that calculates the temperature changes during a phase of the program where a temperature gradient is involved.  So now it is a much more accurate calculation. If you want to, for instance, cool the freezer down 15 degrees over a period of 24 hours, it is able to do that correctly and consistently.

Now it's time to run some more tests on it. AND, the tests that I have planned will at least result in the production of some more home brew... so I've got that going for me...  which is nice.

Thursday, March 15, 2012


Well, I shot past my self-regulated milestone of having a working prototype by the end of February.  Not surprising really, especially if you know me.  Time management is certainly not my strong suit. However, as with any good milestone passer, I have lots of good excuses.  A poker tournament and weekend company took up one full weekend, a friends bachelor party in New Orleans took up another full weekend (more when you factor in the recovery period... on both accounts).  Picking out hardware and electronic components was certainly a time-suck (who knew there were 40 different kinds of 6 amp tubular fuses?).  And most recently, I realized I had to change resistor values on several parts of the circuit, which would normally not be a problem, but I do not have much of an assortment of the surface mount parts, so I had to order some more and wait for shipment.

However, since I've last updated you, I have built the power circuit board**, created all the cable assemblies to connect the internal components together (buttons, LCD screen, temperature module, power, etc).  The cables took a little longer than I had expected; they weren't especially difficult, just time consuming.  I also performed all the power and continuity checks and then programmed the on-board PIC. 

Then.  Finally.  Last night.  It was time for me to breath life into my creation!

 It still has a few bugs related to the circuit that I need to patch up, but for the most part... IT WORKS!  It was a momentous occasion!

You will, however, notice from the picture below, that it needs to learn a little discretion and put another layer on, but we'll get to that (he's going to so embarrassed when he grows up and realizes I posted naked pictures of him all over the internet.)

Anyway, that's all for now.  I've got a case for it and once I get some bugs worked out, my next task is to get it all put together in the case.

****Especially Geeky Power Circuit Explanation****
My power circuit consists of a terminal strip that connects the input and output power cords to the circuit board.  The circuit board then transforms 120V AC power to 6.3VAC power through a transformer.  The 6.3VAC coming out of the transistor is converted to 5VDC through a series of components.  First a rectifier converts all the negative portions of the AC sine wave to positive.  When graphed, this creates a series of humps instead of a sine wave.  A capacitor, which temporarily holds a charge (similar to a very short term battery), evens out the signal to a noisy (wavy) DC voltage.  Then a voltage regulator IC takes the noisy DC signal and converts it to a clean 5VDC signal.  The picture below shows a graphic representation of what each stage looks like. 

Wednesday, February 22, 2012

PCB, easy as 123!

At last! The printed circuit board that I designed has arrived for my fermentation chamber thermostat.  Actually, I received it just over a week ago but haven't had a chance to document it.  I was very happy to see a package from BatchPCB in the mail.  Even more so to find it contained a second bonus board (not sure why, but it will be nice to have another one if when I ruin the first one.)

As expected, I did realize some mistakes that I made (shocking... I know) in the design of the board .  I, for some reason, didn't allow access to the microcontroller chip for reprogramming purposes.  So I had to add another header on the board for that.   I did this by drilling small holes in the pattern of the header into the PCB. Then after placing the header into the holes, I soldered small stretches of 30 gauge wire between the desired contacts.  There's nothing like going at your new prized possession with some power tools to get the blood flowing!

I also decided that the placement of the LED's on the board were too high (with respect to the faceplate of the case), I resolved this issue by placing the headers and LED's onto the back side of the PCB and then installing the board face-down inside the case.  This moved the LED's further down on the faceplate.

So after performing all the necessary changes, I soldered the remainder of the components.  I still have to test out all of the connections before I can add power and start using troubleshooting it, but all the parts are there... and I'm pretty happy about it!  Here's what it looks like:

You can see the little blue "jumper" wires just below the chip that I added to connect the new ICP (In-Circuit Programmer) header (all of the headers are shown in the top pic, what used to be the backside of the board).  I took these pictures before I cleaned the excess flux off of the board, which makes the board look even more sloppy (it certainly doesn't need any extra help).  Flux is a chemical that aids in the soldering process, it cleans the corrosion off the metal connections and allows the liquid solder to cling to the pads and wires.  However, it leaves a sloppy and dirty looking board afterwards.  The good news is that it comes right off with a little rubbing alcohol.

You'll notice that two of the corners of the board have been beveled.  This is so I can slide the board as close to the edge of the case as possible without interfering with the screw holes for the lid of the case. I'll add another post soon of how everything fits in the case.


Tuesday, February 7, 2012


I know you guys are just dying for more information about microcontrollers.  Well, I've just so happen to come across this presentation on the internet (I'm seeing some potential in this...).
This guy will tell you everything that you want to know about microcontrollers and more (probably WAY more).  It's a good presentation regardless of your existing knowledge of the subject.  If you'd like, you can just listen to parts of it , there are bookmarks on the left side so you can jump to different sections to get some overviews.

Check out the link here.

But more importantly, check out that guy's voice!  It's like SILK!   I'd listen to him describe the procession of an episode of food poisoning. Which is probably a good thing since, for some of you, this presentation will be equivocal to such a description.