My DIY temp control

StangMan

SmokeyPitt said:

GregW said:

Nice work.
I probably would do a dry run with a pot of water in the egg to see how it performs.
Are you planning to use PID control or PI?
From my experience PID can be temperamental to setup.
I know some of these controllers have a self-tuning PID loop setup. The controller's I use for other purposes do not, and they are difficult to get PID to control correctly.
Hopefully the self-tuning loop feature will work well for the egg.

My controller has an auto-tune feature and I keep that enabled and it does a fine job. I find it helps if you get the temp in the ballpark first. I see "AT" indicator on @StangMan 's controller so I think that is the auto-tune indicator.

From the research that I've done this unit has an autotune feature that works well. 

My plan is to set the blower to come on 5 degrees below my desired temp and have it turn off at my target temp.

The PID autotune loops learns how fast the fire reacts to the blower and will adjust itself to minimize overshoots.

Toxarch

StangMan said:

Photo Egg said:

StangMan said:

Toxarch said:

Looks nice. Did you put some kind of one way valve after the fan? If not, the natural draft will draw in too much air and you will blow right by your target temp.

I do not. I thought about it but the DigiQ one uses the same blower and they don't use a damper. I'm sure I'll have a few revisions before I get it right.

My BBQ Guru DigiQ does have a slide damper. Depending on desired cooking temp it can be slid open or closed to adjust natural draft when the fan is not running. Thought all their models had this feature.

oh, that makes sense. That should be an easy enough fix. I can add a slider on the intake side of blower. Thanks!

Mine is more like a doggy door. Piece of metal on a hinge after the fan. 

sctdg

I use the cheapest controller you can buy TipTOP and it really works . Put a shoulder on Sunday morn . Set TipTop for 235 . Used Maverick et732 to monitor temps . Inside house had one of my extra Uniden surveillance cameras pointed at Maverick receiver and monitored temps while I was out shopping and visiting my daughter on my Uniden app on my phone . TipTop cost 19.95 and held rock solid at 235 all day .Left at 9:30 am, Home at 3:30 pm . 

eggineric

Which fan did you end up using?  

StangMan

Howdy all! I haven't had much of a chance to fiddle with this thing, but my 1st go didn't go so well. While the controller worked fine I ended up over heating the blower motor and it shut down. (don't worry no meat was harmed ) I had to restrict the intake so much that the motor had to work too hard.

So started thinking, I could eliminate the blower all together and use a servo to open and close a flap on the bottom intake. 

So what do you think, would this idea work? I think someone makes a controller that adjusts the daisy wheel but as far as I know no one controls the intake air.

WeberWho

StangMan said:

Howdy all! I haven't had much of a chance to fiddle with this thing, but my 1st go didn't go so well. While the controller worked fine I ended up over heating the blower motor and it shut down. (don't worry no meat was harmed ) I had to restrict the intake so much that the motor had to work too hard.

So started thinking, I could eliminate the blower all together and use a servo to open and close a flap on the bottom intake. 

So what do you think, would this idea work? I think someone makes a controller that adjusts the daisy wheel but as far as I know no one controls the intake air.

Would you replace the whole vent all together? If you were able to make a whole new vent I could see that working. The stock vent seems to be tight and would probably take a bunch of force to open/close it. I'd imagine BGE keeps it tight so that air doesn't leak into the lower vent when shutdown. 

StangMan

I wouldn't have to modify the BGE. I would just remove the blower from my current setup and replace with a flap and a servo. 

These hobby grade servos are small and very powerful, it shouldn't have a problem opening the flap. 

HeavyG

StangMan said:

Howdy all! I haven't had much of a chance to fiddle with this thing, but my 1st go didn't go so well. While the controller worked fine I ended up over heating the blower motor and it shut down. (don't worry no meat was harmed ) I had to restrict the intake so much that the motor had to work too hard.

So started thinking, I could eliminate the blower all together and use a servo to open and close a flap on the bottom intake. 

So what do you think, would this idea work? I think someone makes a controller that adjusts the daisy wheel but as far as I know no one controls the intake air.

It's been done... a year ago.

Are you familiar with the open source Heatermeter project? A couple members of that community started developing an adjustable servo controlled air intake that works with the blower fan.

I haven't kept up with that project lately but this link should help you out with how that project is going -http://tvwbb.com/showthread.php?63198-The-Adapt-a-Damper-Open-Source-Project

StangMan

HeavyG said:

StangMan said:

Howdy all! I haven't had much of a chance to fiddle with this thing, but my 1st go didn't go so well. While the controller worked fine I ended up over heating the blower motor and it shut down. (don't worry no meat was harmed ) I had to restrict the intake so much that the motor had to work too hard.

So started thinking, I could eliminate the blower all together and use a servo to open and close a flap on the bottom intake. 

So what do you think, would this idea work? I think someone makes a controller that adjusts the daisy wheel but as far as I know no one controls the intake air.

It's been done... a year ago.

Are you familiar with the open source Heatermeter project? A couple members of that community started developing an adjustable servo controlled air intake that works with the blower fan.

I haven't kept up with that project lately but this link should help you out with how that project is going -http://tvwbb.com/showthread.php?63198-The-Adapt-a-Damper-Open-Source-Project

That's kind of what I was thinking of, but would you really need the blower? I think a simple open and close flap or wheel would work.

YukonRon

I just built my anti gravity flux capacitor, 'cept I got nothing to install it on.

Nice build, welcome to the forum.

HeavyG

StangMan said:

HeavyG said:

StangMan said:

Howdy all! I haven't had much of a chance to fiddle with this thing, but my 1st go didn't go so well. While the controller worked fine I ended up over heating the blower motor and it shut down. (don't worry no meat was harmed ) I had to restrict the intake so much that the motor had to work too hard.

So started thinking, I could eliminate the blower all together and use a servo to open and close a flap on the bottom intake. 

So what do you think, would this idea work? I think someone makes a controller that adjusts the daisy wheel but as far as I know no one controls the intake air.

It's been done... a year ago.

Are you familiar with the open source Heatermeter project? A couple members of that community started developing an adjustable servo controlled air intake that works with the blower fan.

I haven't kept up with that project lately but this link should help you out with how that project is going -http://tvwbb.com/showthread.php?63198-The-Adapt-a-Damper-Open-Source-Project

That's kind of what I was thinking of, but would you really need the blower? I think a simple open and close flap or wheel would work.

The Heatermeter can control the fan and vent servo independently. You probably don't need the blower. I can see tho where there may be situations where operating sans blower you may not be able to hold as tight a tolerance on temp swings.

I haven't read thru that thread in many months so I don't know what their usage data is showing as far as fan runtime vs simply opening/adjusting the vent. I wouldn't assume that the fan is always running in conjunction with vent adjustments - the fan may just run when a "boost" is needed.

blind99

StangMan said:

Howdy all! I haven't had much of a chance to fiddle with this thing, but my 1st go didn't go so well. While the controller worked fine I ended up over heating the blower motor and it shut down. (don't worry no meat was harmed ) I had to restrict the intake so much that the motor had to work too hard.

So started thinking, I could eliminate the blower all together and use a servo to open and close a flap on the bottom intake. 

So what do you think, would this idea work? I think someone makes a controller that adjusts the daisy wheel but as far as I know no one controls the intake air.

if you search for 'smobot' you'll find a servo-controlled top damper controller

pretty awesome to see people making their own controllers.  keep up the good work!

dsleight

In my opinion, it will be more difficult to control the temperature with just a vent.  I believe the temperature swings will be greater, but maybe not enough to hurt anything.  Without the forced air, you would have to wait for the updraft to start pulling air in.  There will be a longer delay before the lump starts to take off.  Again, only my opinion.

HeavyG

dsleight said:

In my opinion, it will be more difficult to control the temperature with just a vent.  I believe the temperature swings will be greater, but maybe not enough to hurt anything.  Without the forced air, you would have to wait for the updraft to start pulling air in.  There will be a longer delay before the lump starts to take off.  Again, only my opinion.

The Smobot reportedly works pretty well to control temps so I don't know that a Smobot-like gizmo operating on the intake instead of the exhaust would work much differently.

rmr62

I will bet that when that thing hits 88, you're going to see some serious Shiites

dsleight

HeavyG said:

dsleight said:

In my opinion, it will be more difficult to control the temperature with just a vent.  I believe the temperature swings will be greater, but maybe not enough to hurt anything.  Without the forced air, you would have to wait for the updraft to start pulling air in.  There will be a longer delay before the lump starts to take off.  Again, only my opinion.

The Smobot reportedly works pretty well to control temps so I don't know that a Smobot-like gizmo operating on the intake instead of the exhaust would work much differently.

That device, like the tiptop temp work using a variable flapper.  Using the controller mentioned here, it appears you only control an on/off relay with the temperature.  If the servo can only open/close, it would seem like finding the sweet spot would be based on the range of motion of the flapper.  You would either be open a set amount every time the controller went off or it would be closed, seems like the set-up would be a pain......but I could be wrong.  If the controller can produce a variable signal to the servo, it would work just like the examples mentioned (but on the lower vent).

jbsmith

I have been making a controller with the Inkbird ict 100 and the AT should only be visible in auto tune mode which lasts for 2-5 heat cycles, once the controller learns how you temp rises and falls it reverts to normal operation.
 

pgprescott

HeavyG said:

GregW said:

Nice work.
I probably would do a dry run with a pot of water in the egg to see how it performs.
Are you planning to use PID control or PI?
From my experience PID can be temperamental to setup.
I know some of these controllers have a self-tuning PID loop setup. The controller's I use for other purposes do not, and they are difficult to get PID to control correctly.
Hopefully the self-tuning loop feature will work well for the egg.

I'm not familiar with the OP's specific controller but for this purpose you don't really need to bother with it trying to learn or keep a tight specific temp.

The ones I've used you can set a tolerance - say a few degrees above or below your set temp and just let the average temp be about where you want it.

It's cool that the bigger dollar pit controllers can hold a temp within a degree or two but that is just not really necessary. Hell, my Karubecue cycles in a range of about 15°F above/below my desired temp and that has zero impact on the finished product.

The best ovens you can buy will fluctuate 25-50 degrees. Spot on @HeavyG

nolaegghead

If you were to graph temp vs time, the integral area of the temp would cook about the same as if the temp were perfectly stable.  You could call that the time-weighted average.  Heat = work. 

Of course if you increase the amplitude of the "wave" (imagine it's plus or minus a couple hunnert degrees), you'll have characteristic (like charring of the outside, etc) but, like Newtonian physics, you can plot a cooking rate that's more or less on par with those fluctuations, with the cycle of your average oven. 

Just coded a bunch of stuff for work...in nerd mode.  My apologies.

billt01

if the blower is the culprit, why not just buy a DigiQ or Stoker fan and engineer it to your device? I know that I have used the same stoker fan for 6 years and I have to choke down the ball valve to my stumps to about 25 percent. Also, I think the issue may also be that your controller may not be smart. I know the stoker uses an algorithm to adjust the cycle on and off time. It will actually shut off before it reaches the desired temp. If the cooker never reaches the desired temp with a determined time frame, it will cycle on after a drop of a few degrees and kick back off when its a bit closer to the desired temp. It will continue to do this until the desired temp is reached. this may extend the life of the fan by not working as hard....

Toxarch

Why restrict the fan's intake? Open up the intake and put some kind of simple valve to restrict natural draft when the fan is not blowing.

billt01

@Toxarch I don't believe we want to restrict the fans intake, so much as the output. I Received a new Stoker II for Christmas and I am currently in the process of engineering an adapter with a valve using 1/4 inch pipe. I know on my stumps, If i don't choke down the ball adapter once at temp the temp will continue to rise due to the fact it will start sucking in air through the fan port that is not spinning..

stompbox

HeavyG said:

dsleight said:

In my opinion, it will be more difficult to control the temperature with just a vent.  I believe the temperature swings will be greater, but maybe not enough to hurt anything.  Without the forced air, you would have to wait for the updraft to start pulling air in.  There will be a longer delay before the lump starts to take off.  Again, only my opinion.

The Smobot reportedly works pretty well to control temps so I don't know that a Smobot-like gizmo operating on the intake instead of the exhaust would work much differently.

I can attest that the Smobot works very well.

jbsmith

I live in the UK where its much harder to buy pit controllers.  I have a large BGE and when doing pulled pork for 15+ hours I don,t get a very good nights sleep.  So after reading this thread I was inspired to build my own.

So I purchased the Inkbird itc 100 hv and have connected it up and tested its ability to control temp with the use of a hairdryer connected to controller pointed at sensor (works fine).  I have also ordered a pit viper fan and plate for my BGE. 

I will be testing in the next few days so wanted some advice on how best to set the damper on the pit viper, my thoughts are to get the BGE stable at just below target temp with the use of the viper damper and turn the controller on see what happens.  Is this the correct approach ?

DieselkW

I know nothing, so I'll begin with that.

It looks to me like your fan is too close to the fire grate, could that be the reason for your fan failure, not overloaded by air restriction - overheated by proximity to the flame.

Turn it around, keep the fan outside of the egg, better cooling, same air flow.

Or it's true, I know nothing about what you're doing here.