Integrating functions. You can't do 15 minutes with a 555 timer. You need a CD4020, which has a 15 volt limit. That would mean adding a 12V regulator to the smoke detector power supply to run the timer with...or start with a transformer in the range of 5V to 9V. Opinion: the CD4020 is not convenient to select time because it would go: 4 min, 8 min, 16 min, etc. An adjustable clock would be more convenient. I think you can adjust the clock on that chip.

No, you can't.

 

They lied to get ad space then

When I did my search, it said 5, 10, 15. I felt the 555 could handle it.

kv

 

Still say you guys are over complicating this. Why not just add a bunch of mosfets and other components to a board and consecutively over voltage or otherwise cause them to fail, and let the magic smoke from them do the job?

 

Several questions:
Why are you rectifying only half wave? Is it for the sake of simplicity?

Still say you guys are over complicating this. Why not just add a bunch of mosfets and other components to a board and consecutively over voltage or otherwise cause them to fail, and let the magic smoke from them do the job?

Yum! ... the first batch of ribs coming out of that thing will be for you... see how they taste ...

 

Has anyone Googled' "how a pellet smoker works"? Just the first one I read - http://amazingribs.com/BBQ_buyers_guide/smokers/pellet_smokers.html More here - https://www.google.com/search?q=how...=exZQWKTIHcjbmAG10aiACg#imgrc=pBn7tnrfL8gLuM:

 

@killivolt
How confident are you on that 15 minute timer?
14 to 16 minutes?
10 to 20 minutes?
5 to 25 minutes?
Give me a range.

 

Several questions:
Why are you rectifying only half wave? Is it for the sake of simplicity?

That would be my fault, if you look at my board in post #138 bottom picture, their is a place for a second Diode, but the designer chose not to put it in, it still functions just find.

I think I'll put a video in my Youtube channel and show how it works, I have three resistor locations for an IR Receiver.

Yum! ... the first batch of ribs coming out of that thing will be for you... see how they taste ...

 

@killivolt
How confident are you on that 15 minute timer?
14 to 16 minutes?
10 to 20 minutes?
5 to 25 minutes?
Give me a range.

If I new someone who had a reverse flow smoker, we would know.

I'm just guessing at this point, alton was producing smoke right away so I just thought heat rise and flow should make by 15-20.


kv

 

I'd go 5-25 @#12

kv

 

When I did my search, it said 5, 10, 15. I felt the 555 could handle it.

Try building it with real components. You will find the capacitor leaks so much DC that it never trips the 2/3Vcc comparator.
Say...1000uf being fed with 820K from 17 volts. That says 7 ua leakage with a charge of 11.33 volts and it will never trip the timer. Even 3 ua of leakage and the time constant calculation will wander off the page.

Here's a, "low leakage" cap for $1.20
Calculated at 12 volts, it is guaranteed not to leak more than 24 ua. That's 3X the level of a complete fail.
You could get lucky. You could get a lot less leakage, but your luck would need to be an order of magnitude just to get this into the wobbly range and 2 orders of magnitude to guarantee some repeatability, especially after it depolarizes for 6 months, unused in the garage.

(and that's called, "experience".)

 

Has anyone Googled' "how a pellet smoker works"? Just the first one I read - http://amazingribs.com/BBQ_buyers_guide/smokers/pellet_smokers.html More here - https://www.google.com/search?q=how+a+pellet+meat+smoker+works&tbm=isch&imgil=rLQefDrEGc6QwM%3A%3BYpkmxomY9tc6EM%3Bhttp%253A%252F%252Famazingribs.com%252FBBQ_buyers_guide%252Fsmokers%252Fpellet_smokers.html&source=iu&pf=m&fir=rLQefDrEGc6QwM%3A%2CYpkmxomY9tc6EM%2C_&usg=__kPkOFCz3gbGyT85EuC2mWdUrxTE=&biw=1024&bih=659&ved=0ahUKEwjk8bbYwPHQAhXILSYKHbUoCqAQyjcIsgE&ei=exZQWKTIHcjbmAG10aiACg#imgrc=pBn7tnrfL8gLuM:

While the pellets seem an attractive alternative, the downside is that you practically end up marrying the pellet provider!

I'm still trying to figure out a way to reliably feed chips.... maybe in a continuous way, or maybe in batches... hell, I might even use a claw mechanism if that's what it takes. Our hands are, after all, perfectly adapted for that task.

 

especially after it depolarizes for 6 months, unused in the garage.

Interesting... first time I've heard of that phenomenon. I'll do some googling, see if I can learn more about it.

 

Interesting... first time I've heard of that phenomenon. I'll do some googling, see if I can learn more about it.

Look for, "reforming capacitors". If they didn't leak more after not being used, there wouldn't be any point in re-forming them to reduce leakage.

 

Here's the basic shape of it:http://www.mouser.com/ProductDetail...=sGAEpiMZZMv1cc3ydrPrF0/KYujtVgoKNHZCLwjruME=

 

If you google Bradley Smoker, you'll see a "serious hobbyist / commercial" version of what you're trying to build.

I had a Bradley Smoker, and they're wonderful. Perhaps just buy a control element / circuit from Bradley and build the rest yourself? Their smokers are not cheap, probably because they are *very* well built. I must have smoked 1000 fish / meats with mine over the years I used it.

The only complaint I had with my Bradley was that there wasn't enough space between the "get the pellets smoking" and the smoking chamber, so the smoke was warmer than I would have liked. Building a 1m extension between the "pellets smoking" area and the smoking chamber would have fixed that. Maybe a cooling element, like a fan, would have improved that even more. In summer where I used it, it was difficult to get the smoke cooler than the outside air, which was usually 80F+.

When they make (kosher) lox, they use alder wood, and somehow chill the smoke, so there is no heat at all going to the fish. Because my smoke was too warm, I wound up making smoked salmon instead of lox.

hth

 

Try building it with real components. You will find the capacitor leaks so much DC that it never trips the 2/3Vcc comparator.
Say...1000uf being fed with 820K from 17 volts. That says 7 ua leakage with a charge of 11.33 volts and it will never trip the timer. Even 3 ua of leakage and the time constant calculation will wander off the page.

Here's a, "low leakage" cap for $1.20
Calculated at 12 volts, it is guaranteed not to leak more than 24 ua. That's 3X the level of a complete fail.
You could get lucky. You could get a lot less leakage, but your luck would need to be an order of magnitude just to get this into the wobbly range and 2 orders of magnitude to guarantee some repeatability, especially after it depolarizes for 6 months, unused in the garage.

(and that's called, "experience".)

I have a bag of 1000uF panasonic's I'll check their ESR's Mouser P/N 776-EEUFC1E102L

kv

 

Here's the basic shape of it:View attachment 116810http://www.mouser.com/ProductDetail/Kemet/R82DC3680AA60J/?qs=sGAEpiMZZMv1cc3ydrPrF0/KYujtVgoKNHZCLwjruME=

I'm making a list of my spares, I need to put them in an excel sheet, so I know what I have. I have 2 different types of 555's I think Low Power TLC555 and NE555N, I would need to pick up a CD4020.

I have a bag of Film capacitors 1uF, 2 in series would be half right .50uF? Also have 190k variable resistor.

kv

 

I'll check their ESR's

Equivalent series resistance has nothing to do with leakage current.
Just apply most of their rated voltage and measure the DC current.

 

Equivalent series resistance has nothing to do with leakage current.
Just apply most of their rated voltage and measure the DC current.

I purchased what I could when the Radio Shack went out of business here in Utah.

Didn't know I would get to play around with a 555.

 

I have a bag of Film capacitors 1uF, 2 in series would be half right .50uF? Also have 190k variable resistor.

Grrr! I work so hard to use standard values and keep the price low, then you want to replace a 5% capacitor (44 cents) with something that's 25% off? OK. 0.5 uf will require a pot of 136k. Place 470k in parallel with the 190k pot.