Firmware Version 1.05d Released

A new firmware version has been released and it is now available in the Downloads section of the Support page of the Ohmbrew Automations Website. Updating to this version of firmware is highly recommended.

This is a fairly significant update that addresses quite a few bugs and adds several new features. This version has taken a little longer than I had hoped, but there have been quite a few changes that will not be noticed by the end-user (at least they shouldn’t be). These changes allow the Fermostat to run more efficiently and for easier implementation of future updates.

Continue reading below if you’re interested in the changes implemented.  Or you can just look the firmware release notes for a much more abbreviated list.

Temperature Response Test Feature Update

This firmware version includes an enable/disable setting for the Temperature Response safety feature of the Fermostat. The Temperature Response function checks to verify the system is responding in the manner that the Fermostat is requesting and creates a system error and shuts down if incorrect.  Examples include situations where you plug the heat source into the cold outlet and vise versa, or if the thermostat is incorrectly placed (outside of the system, for instance).  There are a few systems with outlying response systems that were having problems with this feature, so a disable feature was added.

This setting is labeled ‘ResponseEn’ under the Settings section of the menu.

I have also updated the Temperature Response test parameters to account for each temperature scale (i.e. the parameters are different for Celsius versus Fahrenheit).  There have also been several other bug fixes relating to the Celsius scale as a result of more Celsius users helping me test and get the kinks worked out.   Thanks for your help!

Program Review Feature Added

Another sizeable addition to this firmware release is the ability to review a program. This addition required a slight change to the Menu layout.  There is now a ‘Programs’ selection under the main menu.  This was done to simplify the menu a little. The ‘Programs’ selection includes the ability to Add, Review or Remove a program.

The Review selection will show an overview of the selected program. Once a program is selected, it will bring up a screen that shows the Start Temperature, Stop Temperature, Duration and Rate of each step of the program. The Rate column will show either a ‘-1′, ’0′, or ’1′. A ‘-1′ indicates a negative gradient temperature, meaning the temperature is being lowered in this step. A ’0′ indicates that the step is a constant temperature and a ’1′ indicates that the temperature is being raised in this temp.

Step Labels

Another nice change is an improvement to the labeling of a particular step. When creating a program, the ‘Shift’ label option has been removed and ‘ShiftUp’ and ‘ShiftDn’ have been added in it’s place. So any current custom programs you have might have to be re-added or some of your step labels will be incorrect. Besides the label being incorrect, everything else should work fine.


There are quite a few exciting changes coming down the pipeline, so keep an eye out for further updates.  Also, if you have a found a bug or a have a suggestion for a feature or update, feel free to send a note.


Catching up.

So, if you’ve not been following along too closely (and judging by blog attendance, you haven’t :), you would believe that this blog is dead. And that’s an understandable reaction.  However, we have found a weak pulse and are trying to revive it.  And while this blog doesn’t have much for recent information, I have used other avenues to keep people up to date on what’s going on around here this past year.  My goal is to try and consolidate all news/updates so you will be able to keep up regardless of your preferred mode of information delivery (Note: if your preferred method is snail mail… I’m not sure how well we’ll be able to accommodate.)

So, to very quickly get you up to speed: in June of 2013, I started my Kickstarter Campaign, which went exceptionally well!   The remainder of 2013 included finalizing the Fermostat and getting ready for deliveries to Kickstarter Backers.  First thing 2014 the Fermostat’s started delivering!  We are currently accepting Fermostat orders and shipping immediately.

Most of the Ohmbrew updates during this time came in the form of the Kickstarter Updates.  Here’s a link to this info if you’re interested.

Since then, there have been a few Newsletter type offerings.  I’ll do my best to make this information available as well as put links to future newsletters on the blog.  If you are interested in getting the Ohmbrew Automations Newsletter sent to you, you can submit your email address for this on the main Ohmbrew Automations page.

So, I apologize for any discombobulation resulting from the disorganization of information.  I will do my best to, uh, dis-discombobulate in the future…




The Fermostat has been called many things, mostly by me, and well, mostly during childish temper-tantrums and sometimes even while throwing things.  But now, a few more names can be added to it’s cache of monikers: a prognosticator, a seer, maybe even soothsayer… a prophet? OK, maybe a little too far.  I know.. you’re thinking “Wait, could it be? Can it see into the future??“.  And your answer: a resounding “Well, kinda.”

First, a little background on PID Controllers. (buzzkill)  PID controllers create an output based on feedback from an external source (in our case, the temperature of the system).  However, the feedback being used to help control the output is based on 3 factors: a Porportional factor (the current temperature value), an Integral factor (how much the temperature has changed over a period of time in the past), and a Derivitive factor (the current rate of change of the temperature).  These are all basically engineering terms that give the controller a better picture of what it’s output is doing to the system it is attempting to control.

Armed with this information, the controller is now able to predict that the temperature of the system is going to, for instance, drop 0.1 degree every 10 seconds for 50 seconds after the controller shuts itself off.  This allows it to shut itself off before the system has actually reached it’s desired temperature. In this particular example, the controller would shut itself off at 0.5 degrees before it hits it’s target temperature.  This is just an example, but the point is, the number of temperature overshoots, undershoots and oscillations are minimized with the new algorithm that is running the Fermostat.  This allows the Fermostat to keep the temperature of the system closer to the desired setpoint.  Which is much better than the simple set point controls of any other generic off-the-shelf controller that is currently out there.

Soooo… we got that going for us.



I’m a Lager…

Hey all! Just thought I would send out a quick note, since I’m very overdue for some updates.

I’ve finally created some time to brew some beer!  I’m currently using one of the beta units to help ferment a spring maibock lager. Besides being a little darker than I had planned, so far so good.

2013-02-16 21.21.49

I created a new program in the Fermostat suitably named ‘Lager’ (I was in a hurry… didn’t take time to be creative).  It is currently in the ‘Ferment’ stage and will continue to be for several more days before the program slowly increases the temperature up to 70 degrees to allow for a diacetyl rest, then back down to 34 degrees for several weeks to allow for the beer to lager.

2013-02-16 21.21.02

I keep an eye on it from time to time to make sure everything is still on track, but it’s certainly nice not to have to expend the time and effort to keep track of changing the temperature setting!

So, with all this time I’m saving not updating the temperature, I’m currently working on a new batch of beta units that will be dual-stage as well as incorporate a new, more accurate, digital thermometer. These should be ready in another week or two for testing.  I’ll be sure and keep you posted.



Happy New Year and Welcome!

Hello Everybody! Welcome to the new site! The last few months have been a whirlwind of activity. I apologize for not keeping up to date with blog posts. I plan on being a little better in the future.

When I last updated, I had just finished up with the first thermostat and had set about to find some support for the product. Well, I did find some support, in the form of The Cap and Hare Homebrew Club of Fort Worth. There I was able to find the several “beta testers” I was looking for as well as a great forum to get support and feedback. For that I will be forever grateful. Thanks guys!!

After finding the beta testers, I felt I had received enough positive feedback for the product that I could create a business around it and start selling.  I quickly realized that I had a TON of work to do! I then set about some of the tasks required for creating a business: creating a DBA (for now), bank account, creating a web presence, etc, etc. All fun and exciting things, but also time consuming… Building one thermostat was a lot of work, building 10 more in the same fashion was unreasonable, so I had to redesign quite a bit of the device for produce-ability  Designing a printed circuit board was the first step, in concurrence with re-selecting many of the components.  I more than doubled the size of the character LCD from a 2 row by 16 character screen to a 4 row by 20 character screen.  I also changed the user input from an Up, Down, Select type interface to a scroll wheel with a select button.   These two changes were a HUGE improvement to the user interface/user experience (UI/UX). I also changed the microcontroller to a newer model of the Microchip PIC18. The newer model has many more energy saving features as well as more program and data memory to allow for the software additions expected for this new version. The new additions lend themselves to a much better product, however at cost of more design and development time.

So, at this point, I’ve got 10 beta versions completed and have started distributing them to the beta testers.

The new website is up and running, it is still a work in progress, but I believe it is to a point that it is presentable. Feel free to browse around the site and let me know what you think (links are on header at top of this page).  Feedback is always appreciated!

Many exciting things have happened in 2012, and many more exciting things are looming on the horizon!


So, Happy New Year to you and yours, and here’s hoping a great 2013!


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.

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.


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. 

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.