LinkMeter blower???


 

RalphTrimble

TVWBB Diamond Member
Hello,
Recently I ordered all the parts to make a LinkMeterV4 with Raspberry Pi, the first of the parts orders came in today from DigiKey, which included the blower. I was quite disappointed when I got a look at the blower because this thing is tiny? I am wondering if this little blower is really going to be able to properly stoke the fire in my smoker or what? It's really tiny! (less than 3" square by 1" thick)
I had inquired here before about the required specs of the blower but didn't get any replies, so I am asking again for advice on the blower. First of all, what has been your experience with this tiny little blower that's on the parts list for this kit? Secondly, is this system capable of driving a larger blower, if so, what would be the basic specs the fan would need to have to work? Finally, has anyone had success using this little blower, if so, how large was the smoker you were stoking with it?
Any advice on choosing a blower or info about a larger blower you have used successfully would be greatly appreciated.
Thanks.
 
Unless you have a smoker made from a 500 gallon propane tank or something I'd say the fan will work just fine. I haven't heard of anyone where the blower hasn't work. I have heard from many people that the blower is too much and they have to limit the max fan speed. I have to limit my max fan speed. If I don't it blows all the heat out of the smoker and by the time the fire is stoked up again it is so hot it is uncontrollable.

dave
 
Unless you have a smoker made from a 500 gallon propane tank or something I'd say the fan will work just fine. I haven't heard of anyone where the blower hasn't work. I have heard from many people that the blower is too much and they have to limit the max fan speed. I have to limit my max fan speed. If I don't it blows all the heat out of the smoker and by the time the fire is stoked up again it is so hot it is uncontrollable.

dave

Thanks for the reply....
I guess I will just have to wait and see how she blows when I get the circuit built up then... The blower just seems a lot smaller than I expected compared to the blowers I see being sold for use with other smoker controllers like the Pit Viper etc. Then again, I've never seen one of those fans in person so perhaps I am not getting a proper idea of their size from looking at the image?
I see this blower is rated at 6.7CFM, the smaller blowers I see selling for pit controllers is 10CFM and the larger ones are 25CFM. So this little blower isn't too far off from the specs of the small one, but it's way below the larger one. Right now I have a small backyard smoker but I was thinking of making a barrel smoker out of 55 Gal drums this summer, have these fans been used with success on a barrel smoker?
I would still like to know the limits on the blower driver circuit in the HeaterMeter if possible? How much power is the fan driver capable of putting out, in case I want to use a larger fan for a much larger smoker...
 
I have a 55 gallon drum (UDS) smoke with the larger 25CFM fan. Don't get one that big. You really don't need a lot of air flow from the fan. For my smoker I have to practically close the bottom valve the entire way. It is open about an 1/8", then I limit the max fan speed to 50%.

If you go look at the damper thread, most people want a way to reduce the air flow. The main reason is that there is air flow created by natural convection. If there wasn't you wouldn't be able to use the smoker without a fan. So to get the fan to work well adjust your smoker to run slightly cooler than your target temp, then add the fan to make up the difference. When I smoke at 225F, I set my UDS valve to hit about 200F without a fan. I then just need enough fan to raise the temp 25F. That isn't a very big fan. So don't think of the fan having to provide all the air, just enough to incrementally increase the temp from where it would naturally run without the fan on. This works for me whether I'm running it at 225F or 350F, I just open the bottom valve a little more. The reason it works this way is because there is no damper in the home made fan, so the air can flow through the fan even when it is turned off.

Hopefully this makes sense. I still think your are fine with the smaller fan.

dave
 
....I have a 55 gallon drum (UDS) smoke with the larger 25CFM fan. Don't get one that big. You really don't need a lot of air flow from the fan. For my smoker I have to practically close the bottom valve the entire way. It is open about an 1/8", then I limit the max fan speed to 50%.....

dave

OK, thanks for the advice. I was thinking of the system being a little more sealed off when running it with the blower. Even with your example above with the 25CFM fan limited to 50%, that's still twice as much capacity as this little blower I have here.... Anyhow, I've got this one for now and if I end up lacking capacity I guess I can seek out another fan later.

Can I assume you are running your 25CFM fan with a standard HeaterMeter? I did beef up the power supply I ordered to 2A, was only like two bucks more....
 
I use a sony sf22c fan on a small Pitts & Spits offset smoker, which supposedly puts out 38cfm. I found it in a parts bin at the local electronics shop, but looking up the specs online it claims to draw .51 amps at 10V. My power supply is a 2A.

As Dave says you don't need much fan to operate the smoker once it reaches temperature. The key to making my rig work was to gasket the lid and the firebox door, so that it is much tighter and like he says restrict the airflow to what would be a lower temp without the blower running. Otherwise there is no way to bring the temp down when you overshoot the target temp.

My fan will hover around the 15% range when everything is set up correctly, when it climbs to above 50% then it's time to add another stick of wood. Hey - I need to check if an alarm can be set on fan speed !
 
I'm having trouble with my Big Steel Keg getting TOO MUCH air with the spec'd blower (even when off, the open area is too large). It won't run well below 275* w/o choking down the intake on the fan & the top vent. Holds stable at 275*, need some time to play around with how much to choke the fan down & have it run lower.
 
I'm having trouble with my Big Steel Keg getting TOO MUCH air with the spec'd blower (even when off, the open area is too large). It won't run well below 275* w/o choking down the intake on the fan & the top vent. Holds stable at 275*, need some time to play around with how much to choke the fan down & have it run lower.

I shouldn't comment cause I haven't actually built and run a HeaterMeter yet, but...

I am under the impression that you need to choke down your smoker enough so you can actually choke off the fire and reduce the temperature when the fan is not running, otherwise your temp can rise too high just from just natural convection. This way the fan can stoke the fire and make the temp rise, or not stoke the fire and cause the temp to drop, and thus have the ability to fully regulate the temperature in the pit. Is your pit completely closed up besides the opening through the fan and its still running over temperature?

I've done a lot of reading on the HeaterMeter project today, just finished reading the entire 47 page thread in the forum about the development of the HM and got a lot of answers to my questions, in case anyone reads this thread looking for answers to the same questions...

The fan runs at 12VDC and the speed is controlled via PWM (Pulse Width Modulation), it does not vary the voltage to control the fan speed, instead it will pulse 12VDC, the longer the pulse the faster the fan spins. Somewhere in that 47 page thread I recall reading the mosfet circuit used to drive the fan is capable of putting out a LOT more power than this little fan requires, I don't recall the exact numbers but the overshoot on the driver capability was way high. Something like this little fan in the parts list takes less than one watt and the driver can handle 30 watts or more. (I don't recall the exact numbers, but the driver should be able to push a very large blower, much larger than would ever be required). The only thing you need to worry about if you do require a larger fan is that your power supply is large enough so it doesn't brown out the controller when the fan kicks on. I already beefed up the power supply to a 2A model with this in mind when I placed my order...

But.... as has been suggested already in this thread, basically you want the fan to push the smallest amount of air possible to stoke the fire and hit the target temperature in the pit, if you pump too much air with the fan you are just pushing heat out of the pit and wasting your fuel. So you setup your manual dampers on the pit to undershoot your temp a bit and then let the fan stoke the fire up to temp and do that last little bit of fine tuning, which shouldn't require much air flow from the fan. (I'm learning...)

Speaking of orders... Digikey came in first place, took only a couple days for them to deliver, Mouser was one day behind them. OSHPark just shipped my HMv4 PCB today, I ordered five days ago. Amazon is pulling up last position having just shipped my order today, although I went with their "free super saver" economy shipping which means they wait for all my stuff to be in one place and then put it in one box to ship to me on the slow boat to china plan! LOL Looks like I will have all the stuff in my hands and ready to build next week! I'm pretty "stoked".... LOL

Many thanks to everyone who made this project possible...
 
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Hey Andy, we really have to limit the air getting in the keg. You probably know how long it takes to get it back down to temp if you overshoot ;) My HM isn't quite done yet and I currently use a DigiQ II with the 10cfm blower on my keg, which has a built-in damper (I'll be reusing that with the HM).

Keggers with a Pitmaster IQ (no built-in damper) typically tape most of the vent holes to limit convection air flow, like this (from the Keg FAQ page) ...

n25VJ.jpg


Maybe something similar will work for you?

(PS. Love the lego case!)
 
Ralph - I had the fan intake & the top vent at a sliver. The problem I had was condensation plugging the top vent, then no flow. If I opened the vent enough to get flow,I overshot.
I've only used the HM 1 time on a butt smoke. At 275+, it works awesome. I got overconfident after only using it at 400* 2x & went for an overnight, unattended smoke at 225* & got no sleep....
basically, i need more testing & less 'throw it together & go" I had a similar ID10T problem doing a butt w/o any temp controller. In January. In the snow.....
(Pocket protector installed) I measured the area of open intake w/o fan @225* & it is about 30% less than my fan passage. So Fan + natural flow = WAY over 225*. I'm going to block the fan passageway ~ 50% so the fan can run a bit (/pocket protector). Need time to do that & test, but I've grilled every night this week that I've been home..... Hard to do the sealing when the Keg is at 500+

D - I REALLY like the keg, but it sucks when you overshoot temp. I'm not patient. I got it for Xmas, for less than a large Egg. Dad has an egg & I use less lump and can hold temp better. Made some really good food (also screwed some up as I'm still learning. had some HUGE chicken breast tonight that got a bit tough & dry as I cooked them at 550 like I've been doing normal size pieces. too hot).
 
Andy, it'd be a good idea to check in on the Keg board for cooker specifics if you're not already there.

You'll find all sorts of helpful information already there (FAQ and search), and plenty of helpful people (myself included) to answer questions.

Chicken is a max 450* (350-400 preferred) direct cook for me, time depends on a few things, but usually pulled when the IT hits 165.

Overshoots are a tough one for us, so most will keep an eye on the ramp up and start throttling back 50-100deg before goal temp. Unfortunately, you have to be patient for that :)
 
Yep I'm on the Broil King forum, don't think I've posted, but read a lot before buying.
I've been doing chicken at 5-550* & it worked well (I usually pull a bit early). I didn't like it at 400*, so I went up a bit. Mostly boneless/skinless breasts. these were HUGE (I at 1/2 of one for dinner tonight...) My wife won't eat anything if she even suspects it's not been forged in nuclear fire, so I made sure I got the thick ones done, but overdid it a bit. Still juicy, but tough. I don't usually use temp probes on chicken or chops, just calibrated eyeball. Might have to start.
 
Hello everyone,
Just completed my HM and tested it out last night on my Vision Kamado. My blower setup is from BBQ Guru using the 10cfm Pit Viper. My issue is at low fan power settings the fan will not rotate (I hear the PWM buzz). Once the fan power gets above 50% then the fan will kick in. Once it kicks in and begins spinning and coming up to temp it will ramp down but die at low percentages. Power is definitely being applied as I can hear the buzz from the PWM signal but it just doesn't seem to be enough. Is the Pit viper fan the wrong fan to use? I have already ordered the fan identified in Bryan's part list from Digikey and will need to figure out a way to attach to the Vision as it seems to have a square exhaust where as the pit viper and its attachment to my kamado is circular.

Any one having the same issues?
 
Hello everyone,
Just completed my HM and tested it out last night on my Vision Kamado. My blower setup is from BBQ Guru using the 10cfm Pit Viper. My issue is at low fan power settings the fan will not rotate (I hear the PWM buzz). Once the fan power gets above 50% then the fan will kick in. Once it kicks in and begins spinning and coming up to temp it will ramp down but die at low percentages. Power is definitely being applied as I can hear the buzz from the PWM signal but it just doesn't seem to be enough. Is the Pit viper fan the wrong fan to use? I have already ordered the fan identified in Bryan's part list from Digikey and will need to figure out a way to attach to the Vision as it seems to have a square exhaust where as the pit viper and its attachment to my kamado is circular.
Any one having the same issues?

What size power supply do you have powering your HeaterMeter? I think I recall reading the fan driver circuit in the HM should be able to put out 30W or so if you have a power supply that can put out enough current, which should be good enough for your pit viper fan I would think. Seeing how the fan spins in the higher range I guess that kinda sounds like the power supply is strong enough, so that's kinda conflicting... Perhaps there is some software setting that can be adjusted when using a different fan? Hopefully Bryan will chime in on this....
The output of the fan used in this project is indeed square, or a bit rectangular at about 1" X 1.175" outer dimensions. Hopefully you will be able to get your pit viper fan working, cause it would be a shame to have to toss it aside and rig up something to connect the square fan to your smoker when you have such a nice screw-on adapter on the pit viper already. (I assume)
 
What size power supply do you have powering your HeaterMeter? I think I recall reading the fan driver circuit in the HM should be able to put out 30W or so if you have a power supply that can put out enough current, which should be good enough for your pit viper fan I would think. Seeing how the fan spins in the higher range I guess that kinda sounds like the power supply is strong enough, so that's kinda conflicting... Perhaps there is some software setting that can be adjusted when using a different fan? Hopefully Bryan will chime in on this....
The output of the fan used in this project is indeed square, or a bit rectangular at about 1" X 1.175" outer dimensions. Hopefully you will be able to get your pit viper fan working, cause it would be a shame to have to toss it aside and rig up something to connect the square fan to your smoker when you have such a nice screw-on adapter on the pit viper already. (I assume)

Ralph,

Power supply is a wallwort putting out 12V at 1.5A. I could look for something with a little more umph as long is it does not damage any of the other electronics. The Pit Viper and the attachment for the Vision is a nice setup. Would be a shame to have to swap it out. I looked in the code to see if there was any thing I could change but did not see anything Hopefully Bryan will see this and chime in.
 
I'm running a 2A wallwart, as long as it's 12VDC it wont cause a problem. The amperage is just how much current it can supply at the rated voltage, extra current doesn't cause a problem unless there is a short circuit there to draw it.

I think a 1.5A power supply should be more than sufficient, and thinking about it further, the reason to up the amperage on the power supply when running a larger blower is to prevent a brown-out/reset on the HM or rPi when the fan draws current, and I don't think you have that happening?

I would check the value and orientation of C1, D1 and R3 (22uf/25V, 1n4001, and 1K, respectively) as well as the ground on that portion of the circuit. Also, on first power-up I had some issues where solder didn't flow to the component side of the board on the IC and IC socket, so you might want to check them out and see if the traces under the chips are still showing gold or covered over with silver solder? If still gold re-solder them again so the solder flows to the other side of the board. Finally, what are you using for a wire to connect your fan to the HM? Perhaps theres an issue there? (internal resistance?)

Just throwing out thoughts on this issue, hopefully might help you work it out...
 
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Cable to fan is quit long. I will shorten. Also I will confirm solder flow and orientations and values as well. Parts are covering reference designators. is there a board layout showing the component ref des?
 
Parts are covering reference designators. is there a board layout showing the component ref des?
I've also just put up a image of the board in EAGLE if that helps. Remember this is looking from the top down so all the components are mirrored from where they'd be if you were looking at the component side.

As I said in the PM I sent you though, it probably just doesn't have the power to start the fan until after it gets to 50% power. You can either raise the Min Fan Speed to 50% or you can increase the value of the 22uF 25V capacitor C1 (the cap adjacent to the blower jack) to maybe 47uF which will give it a little more oompf. If you just have another 22uF 25V cap, you can touch it to the existing capacitor leads to test and see if it lowers the minimum required fan speed (caps in parallel can be added so 22+22 = 44uF)
 
Sounds like Bryan gave you two viable solutions....
I would note that if/when you are tapping a second capacitor across the first (to double the capacitance of C1) to see if that will kick your fan in at lower RPM (and it just might), make sure you match the caps polarity.
If the capacitor change doesn't get her rolling it sounds like setting the min fan speed to the speed where your fan kicks in should work too. I'm wondering when it starts up at 50% how fast is it going? Does it start right out blowing like crazy or does it run like it is at much less than 50% capacity? If it starts out slow then it seems setting the min fan speed to 50% should work out fine. However, if the fan does come on blowing half capacity, which would be 5CFM for your fan which is near full capacity of the stock HM fan, that would be like going from 0-100% when you just want to go from 0-1%, which obviously wouldn't be good (unless you had a super large pit I guess).
Hope you work it out with the pit viper fan, post back if you find a solution for the next guy to read...
 

 

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