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View Full Version : Newbie; referred by a friend; need gradual temperature changes



Bill Velek
08-09-2004, 03:11 AM
Hi. I'm new here and have been referred by a friend who thought that I could find the type of electronics that I need for a home project. Now I have spent _days_ searching the Internet for what I need, but I just can't find it.

Essentially, I want to monitor and control temperatures in an ice box from a high of about 70F/21C down to a low of about 34F/1C. Prefer to be able to have a continuous _gradual_ drop in temps as much as possible, although stepping is fine if that is all that is available. Maximum temp change should not exceed 5 degrees fahrenheit per day, and I would prefer as tight as a 2F/1C per day.

This is not a commercial application. It is for a piece of homemade brewing equipment that I designed and built myself. It currently uses a standard home thermostat to cycle a small CPU-fan on and off, with the fan drawing air through an insulated compartment full of ice, into a second insulated compartment in which a conical fermenter is suspended. This is presently used for fermenting ales [home brewed beer], but I'd like to try to ferment lagers [different beer] which require very special temperature control.

However, if continous temperature drop is not possible, I can manually make a one degree adjustment every 12 hours or so. Therefore, at the very least, I need a digital thermostat with a display that can be mounted on the outside, and a probe placed on the other side of a 2" thick wall of paneling and styrofoam insulation. Because I might choose to also employ either a light bulb or heating-strip (like the ones to keep pipes from freezing), I'd prefer a dual function -- heating/cooling -- type of thermostat.

Any help will be greatly appreciated.

Thanks.

Bill Velek

K de Jong
08-09-2004, 05:16 AM
Hi Bill,

From the programming and controlling point of view this could be done fairly easily with a Stamp. The easyest way to go would be a simple ON/OF thermostat, this keeps the temperature between the limits you choose, ie 1 or 2 degrees C. Of course, there must be enough cooling power available to do so.

It will also be possible to construct a PI controlling device with the Stamp using its PWM output as an analog output to proportionally control your device.

From the process side of your brewing project I have a couple of remarks.

1 you have a small brewing vessel, I guess. Small fermentation vessels tend to need extra heat for fermentation while industry scale large vessels are more likely to need cooling.

2 why do you use Ice for cooling, not a cooling machine? An old frig or air conditioner?

You know that Lager or Pilsner beer became popular after the invention of cooling machines in 1870 http://forums.parallax.com/images/smilies/smile.gif.

Succes,

Klaus

Chris Savage
08-09-2004, 10:23 PM
Is it me, or is this thread on here twice?



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Chris Savage

Knight Designs
324 West Main Street
P.O. Box 97
Montour Falls, NY 14865
(607) 535-6777

Business Page: http://www.knightdesigns.com
Personal Page: http://www.lightlink.com/dream/chris

Bill Velek
08-10-2004, 01:26 AM
Chris Savage said...
Is it me, or is this thread on here twice?


Chris, I need help with this blasted system. I guess that's what happens when an old fart is also a newbie.

Anyway, I'm just trying to find out how to use the interface on this forum, and frankly I don't find it very intuitive except for the emoticons that I'll seldom use anyway. Unfortunately, in stumbling around here, I've done a lot worse than posting the same message twice (which probably happened because, IIRC, when I posted it the first time, it asked me to do something like join or whatever, and then -- not realizing that it had posted the message -- I used my back button on my browser and then posted it (apparently a second time).

Anyway, what I just did that is much worse is, while trying to figure out what the controls are (they're not labeled), I had intended to respond to the previous poster in this thread, and hit the button to put him in a kill file to ignore him, or whatever. That was unintentional, and now I can't find a way to undo it. Not a very impressive interface, but maybe it's just my stupidity ... and since I'm here begging for info, I'll try to adjust to it as quickly as I can.

So, ...

1.) Can you advise me how to _UN_-ignore a poster?
2.) I apologize for the duplicate post, but trust that it should not happen again with me ... I _hope_.
3.) I wanted to respond to the previous post, but can't see it now to remember everything that was mentioned, so I'll shoot from the hip:

Homebrewers generally require cooling more than heating. The ideal temp for fermenting ales is about 68F/20C, and for lagers it is in a range from about 55F/13C to 45F/7C -- with lagering to condition is gradually being dropped to as low as 34F/1C. The only time that a fermenter would be heated is if it is done outside in cold weather.

The reason I can't use a converted chest freezer is because this particular fermenter is a conical (basically a cylinder with a funnel on the bottom), which requires a stand to support it, plus it is too tall for a chest freezer. I'm also sure that I would not be able to fit more than just one in an upright freezer or refrigerator. I therefore built my own insulated cabinet, which turned out very nice. The ice is more than adequate to cool it and keep it cool; it is kept in a separate insulated compartment which holds 4 gallons (about 30 pounds of ice).

Now, to reiterate what I'm looking for, I need a panel on the outside of my cabinet which will monitor and control the temp on the inside by a probe that can be placed on the other side of the wall (thickness is 2 inches/5.1cm). It needs to have an operating range from 70F/21C to 34F/1C. Ideally, it will be programmable to automatically drop the temp 2F/1C degree per day. It will regulate a 12vdc fan for cooling, but also being able to control a small heating element would be a 'plus' in case I decide to do some lagers outside in the cold weather.

Thanks.

Bill Velek

Bean
08-10-2004, 01:39 AM
I wonder if a peltier device(s) would do the trick.

Bean.

Bill Velek
08-10-2004, 02:04 AM
Bean said...
I wonder if a peltier device(s) would do the trick.

Bean.


There are occasional discussions on homebrewing forums about them. I've considered them, and they don't seem to be worthwhile for the money they cost, and I don't know of any serious homebrewers who have done anything with them. I definitely wouldn't cut a hole in my conical to experiment, but thanks for the thought.

Cheers.

Bill Velek

Chris Savage
08-10-2004, 02:05 AM
Bill Velek said...

Chris Savage said...
Is it me, or is this thread on here twice?

Chris, I need help with this blasted system. I guess that's what happens when an old fart is also a newbie.

Bill,

I apologize if I sounded like I was being mean, I wasn't...When I read the one copy of the thread, it appeared at the top of my list, but the other copy was the next thread to read, so I got confused. Yes, I knew there were 2 copies at that point, but wasn't sure which one was valid, perhaps Jim (IT Guy) should remove a copy?


Bill Velek said...
Anyway, what I just did that is much worse is, while trying to figure out what the controls are (they're not labeled), I had intended to respond to the previous poster in this thread, and hit the button to put him in a kill file to ignore him, or whatever. That was unintentional, and now I can't find a way to undo it. Not a very impressive interface, but maybe it's just my stupidity ... and since I'm here begging for info, I'll try to adjust to it as quickly as I can.
So, ...
1.) Can you advise me how to _UN_-ignore a poster?
2.) I apologize for the duplicate post, but trust that it should not happen again with me ... I _hope_.
Well, bashing yourself isn't going to help you, but someone on here can. Perhaps myself, we shall see...You'll figure things out with a little bit of time. There are a lot of people ready to help! As for un-ignoring someone, I think you go into edit options, or edit subscriptions or one of those...I can't see now while I am replying. But check the control panel area.

Bill Velek said...
Now, to reiterate what I'm looking for, I need a panel on the outside of my cabinet which will monitor and control the temp on the inside by a probe that can be placed on the other side of the wall (thickness is 2 inches/5.1cm). It needs to have an operating range from 70F/21C to 34F/1C. Ideally, it will be programmable to automatically drop the temp 2F/1C degree per day. It will regulate a 12vdc fan for cooling, but also being able to control a small heating element would be a 'plus' in case I decide to do some lagers outside in the cold weather.
Thanks.
Well, if I am correct in what I think you're looking for, you could use any standard plastic proto-typing box to build a BS2-based controller inside. The BS2 could monitor the inside temp (Perhaps using an LM34 or DS1620, not sure of the ranges off-hand) and control a fan and/or heater element (There are many ways to do this). If you think this might be what you need, we can go from there.


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Chris Savage

Knight Designs
324 West Main Street
P.O. Box 97
Montour Falls, NY 14865
(607) 535-6777

Business Page: http://www.knightdesigns.com
Personal Page: http://www.lightlink.com/dream/chris

Shawn Lowe
08-10-2004, 05:07 AM
I have posted a reply on the yahoo list, but here goes.
You can purchase a commercial tempurature controller. Check out www.williamsbrewing.com. About 100 bucks. But if you want to build it yourself, you can program alot more features. However, your end price will be the same if not more than the commercial controller. You get the benefit of an education if you go the Basic stamp route though.

Shawn Lowe

P.s. do you extract brew or all mash?

Bill Velek
08-10-2004, 06:09 AM
Okay, I'll do the best I can with the format of this forum, but I hope I don't accidentally send this message while I'm trying to format stuff. What I'm trying to do right now is quote portions of the last post; I can't see where this is automatic like usual in most places.


Shawn Lowe said...
You can purchase a commercial tempurature controller. Check out www.williamsbrewing.com. About 100 bucks.


Thanks. I just checked, and it doesn't do everything that I want -- at least not enough to spend a hundred bucks. For instance, it doesn't appear to be programmable to gradually lower the temperature at a somewhat constant rate.


Shawn Lowe said...
But if you want to build it yourself, you can program alot more features. However, your end price will be the same if not more than the commercial controller. You get the benefit of an education if you go the Basic stamp route though.


I'm looking into that right now, as well as your other suggestions in your longer post via yahoo-groups, e.g., Dallas
semiconductors, etc.

Cheers.

Bill Velek

alinious
08-10-2004, 09:25 AM
Hey Bill,

Dallas Semiconductor makes a thermostat device (DS1620) in the form of an IC. In fact, Parallax sells the DS1620 which has a range of -67F to +257F in units of 0.9F. Here is the link which contains a PDF file that demonstrates how to interface the DS1620 to the BS2 and source code examples (http://www.parallax.com/detail.asp?product_id=604-00002).

Hope this helps,
Alan

Chris Savage
08-11-2004, 04:48 AM
Bill Velek said...

So, ...
1.) Can you advise me how to _UN_-ignore a poster?
Thanks.
Bill Velek
Bill, were you able to un-ingnore the user given the information I gave to you? To clarify, it was Control Panel, then Edit Ignored Users.


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Chris Savage

Knight Designs
324 West Main Street
P.O. Box 97
Montour Falls, NY 14865
(607) 535-6777

Business Page: http://www.knightdesigns.com
Personal Page: http://www.lightlink.com/dream/chris

Bill Velek
08-11-2004, 05:06 AM
Chris Savage said...

Bill Velek said...


So, ...
1.) Can you advise me how to _UN_-ignore a poster?
Thanks.
Bill Velek
Bill, were you able to un-ingnore the user given the information I gave to you? To clarify, it was Control Panel, then Edit Ignored Users.


Yes, and thank you. Sorry I didn't respond to you earlier. I've been running around in circles trying to chase down leads from a lot of different folks. It's great that so many people are trying to be so helpful. Unfortunately, I'm having to cope with limited ability to understand all of the answers and suggestions.

I also haven't overlooked your suggestion that you might be able to possibly help if I go in the direction of building a BS2-based controller, but I've been hoping and looking for something that will be close to my needs right out of the box because I don't want to impose to the degree that I'm afraid would be necessary.

This is really frustrating. I know that the reason I'm having trouble finding what I need is because this is such a specialized requirement that there probably isn't any one commercial product that will do it all. On the other hand, there is no question that the technology is out there, and that this could probably be done rather easily if I just new how to design the circuit I need. I had hoped that there would be something like the equivalent of a Radio Shack project that I could use, or that maybe someone had done something like this and posted the info on a usergroup on website. But so far, no such luck.

Now, as for a project to build something of my own, here is part of an email message that I received from a very nice fellow:
"You used to be able to buy a cheapo radioshack item with a thermistor probe and a settable alarm. You could wire the alarm to turn on a heater or cooler and that would likely work. However, there are better controllers such as PID (proportional, integral, derivative) and I happen to have one I could give you especially since I have no use for it and there is no more a noble cause than brewing beer. ... Please send me your address and I will send the controller. It is a small ~5cm x~5cm controller. It is up to date so instructions can be found on the web for programming it. It takes a k-type thermocouple (cheap). I dont think it does ramping - sorry. You will just have to change the setpoint manually every 6 hours. If you size your heater/cooler properly it will approximate a ramp anyways."

So, that seems encouraging and might be just what I need with a few additional parts. Does it sound like I might be able to put something together that will approximate my needs? Remember that I mentioned that I could get by without programming, if need be.

Anyway, thanks again. I'll keep checking and if I ever find an answer I'll be sure to let you all know, too.

Cheers.

Bill Velek

Chris Savage
08-11-2004, 07:03 AM
Bill Velek said...
Yes, and thank you. Sorry I didn't respond to you earlier. I've been running around in circles trying to chase down leads from a lot of different folks. It's great that so many people are trying to be so helpful. Unfortunately, I'm having to cope with limited ability to understand all of the answers and suggestions.

Well, as I said, we're here to help. If you don't understand something, I'm sure someone will explain it to you.


Bill Velek said...
I also haven't overlooked your suggestion that you might be able to possibly help if I go in the direction of building a BS2-based controller, but I've been hoping and looking for something that will be close to my needs right out of the box because I don't want to impose to the degree that I'm afraid would be necessary.
without programming, if need be.


---trimmed---

Anyway, thanks again. I'll keep checking and if I ever find an answer I'll be sure to let you all know, too.
Cheers.
Bill Velek

Well, being an engineer/tinkerer, I always see people's needs in terms of wanting to build it themselves, although that is often not the case. I remember sometime ago someone mentioning needing a thermostat for a heating system. I assumed (Don't say it Jon! http://forums.parallax.com/images/smilies/smilewinkgrin.gif ) that they wanted to build one...However, they didn't want to "re-invent" the wheel...Me on the other hand, I will always build something instead of buying it, if I can. That goes for Stereos, Alarm Systems, Thermostats, etc.


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Chris Savage

Knight Designs
324 West Main Street
P.O. Box 97
Montour Falls, NY 14865
(607) 535-6777

Business Page: http://www.knightdesigns.com
Personal Page: http://www.lightlink.com/dream/chris

Bill Velek
08-14-2004, 11:23 PM
To Everyone:

Thanks for your help and offers of help. I am still looking into this, and will post updates as I make any progress toward a solution.

To Shawn Lowe:

Sorry I forgot to answer the question in your P.S. I am currently an extract brewer, but am building my equipment to go all grain. Will probably do an all grain batch in the next few weeks ... I HOPE.

Cheers.

Bill Velek