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Koffee Kosmo
OfflineAdmin
· 08/28/2020 7:15 PM
I have updated my signature and added links to the KKTO roaster build

snwcmpr
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· 08/16/2020 8:12 AM
I will say, it only happened once, briefly, to me.

NetriX
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· 08/16/2020 7:57 AM
I was blocked too, our hosting provider is dropping the ball lately. thumbdown

Koffee Kosmo
OfflineAdmin
· 08/12/2020 5:37 PM
And I thought it was just me that couldn't access the site All good now - coffee kept me company

JackH
OfflineAdmin
· 08/10/2020 8:46 PM
Had to make myself another cup of coffee to get through it.

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Arduino PID controlled popper
mtbizzle
Hey all, first post. I have a burning desire to make an Arduino-PID-Artisan set-up. I have a nostalgia popper and was thinking of modding that. As I have 10 days free soon, I'm hoping now is the time cross fingers

Big thing holding me back is that I have no background experience w/ coding, Arduino, or electronics. I'm good at following steps with DIY projects, but that stuff will be new to me.

My plan is to use this guide --
https://medium.com/@lukasgrasse/how-t...a3334fd7d5

Or to use this TC4 popper guide https://www.instructables.com/id/Ardu...e-Roaster/

(Any advice which I should go for?)

It seems more like an outline than a step-by-step. Any advice re. translating this guide to a working PID popper setup would be amazing. Recommending parts (eg, the MAX6675 Thermocouple w/ breakout he used is discontinued), directing me to other resources -- anything would be appreciated! At this point I'm trying to plan and finalize a shopping list so I can buy parts next week.

It's a bit disorienting reading up on the project w/o background knowledge of coding, electronics, etc, but I'm sure I can figure it out with all the resources there are online.



My W.I.P. notepad:

Shopping list:
* Arduino Uno R3 ($20.50) - https://www.amazon.com/dp/B008GRTSV6..._lig_dp_it
* 40A solid state relay ($3.33) - https://www.aliexpress.com/item/20351...73599.html
* Solid state relay heat sink? ($2) - https://www.aliexpress.com/item/32656...416bb1QIV9
* MAX6675 thermocouple w/ breakout - ? (replacement MAX6675 and good sensor for use inside popper? ) - K type? RTD? - https://www.adafruit.com/product/3984
* Appropriate breadboards? (half-size, like this? https://www.adafruit.com/product/64)
* Materials for mounting / enclosing circuits? - maybe this https://www.adafruit.com/product/275
* Cheap, used Windows laptop from eBay (for running Artisan)
* MOSFET transistor - V and amp requirements unknown? - https://www.adafruit.com/product/355 or https://www.adafruit.com/product/1794
* Extension cord - standard part
* Wires - standard part - breadboarding wire set here - https://www.adafruit.com/product/153
* Multimeter, solder, iron (have)
* Nostalgia popper (have)


Wiring:
* Separate heating from rest of circuitry per here - https://ineedcoffee.com/west-bend-pop...roasting/
* Schematic for heating element circuit - https://miro.medium.com/max/1400/0*gN...5J1zoe.jpg

> This setup ends up having two circuits - is that right? Fan plugs directly into wall, heating element is on a separate circuit thru the Arduino?



Software:
* "Upload sketch using Arduino IDE"

* Using Library Manager - https://www.arduino.cc/en/Guide/Libra...aries#toc3 --
> Install MAX6675 library https://github.com/adafruit/MAX6675-l...75-library
> Install ModbusRTU library https://github.com/smarmengol/Modbus-...or-Arduino

* Artisan Config & PID control

Software edits, per user comments

* "For reference, on my popcorn roaster I use P=5, I=0.05, D=30."

* "to get Artisan to use it’s PID and control the temperature automatically, under the config > port menu, in the PID section change the Slave to 0 instead of the 1 in the picture above."

* "In Artisan change Modbus connection Parity option from “E” to “N”"

* "Change the code:
slave.begin( 19200, SERIAL_8E1 ); // 19200 baud, 8-bits, even, 1-bit stop
to
slave.begin( 19200 ); // 19200 baud, 8-bits, none, 1-bit stop

* To obtain a decimal value in Artisan (which smoothens the ROR graph)
Change the code:
au16data[2] = ((uint16_t) thermocouple.readCelsius()*100);
to
au16data[2] = (uint16_t) (thermocouple.readCelsius()*100);"

* "I think the pins are not set correctly in the sketch
The original sketch shows
“int thermoDO = 4;
int thermoCS = 2;
int thermoCLK = 3;”
In my opinion this does not make sense. If you want to directly connect (soldering or
breadboard) the original Adafruit MAX6675 module (PIN sequence gnd, vcc, do, cs,
clk), you should change it to:
“int thermoDO = 4;
int thermoCS = 3;
int thermoCLK = 2;”
Be aware that some cheap third-party clones (including mine) have a different PIN
sequence (gnd, vcc, clk, cs, do). For these you have to exchchange the pin numbers of
thermoDO and thermoCLK."


Cheers coffee drink
Edited by mtbizzle on 04/22/2020 7:56 PM
 
btreichel
#1 is easier, #2 is more full featured
 
mtbizzle

Quote

btreichel wrote:

#1 is easier, #2 is more full featured


#1 it is, then. Or maybe this new guide -- https://github.com/austinj/arduinosan -- because finding the parts for #1 may be an issue.

Trying to get my shopping list finalized. I figure the easy part will be the electronics, the hard part being the software.

Issues:

* Don't know amp/voltage ratings for MOSFET transistor? Doesn't seem to be listed in the guide.

* The MAX6675 chip they used has apparently been discontinued. Replaced by MAX31855 -- but "not pin compatible or drop-in code compatible with the MAX6675." thumbdown

* Another user recently posted a guide that uses the MAX31855 -- https://github.com/austinj/arduinosan -- does this allow for PID control? I'm guessing not - no solid state relay? - if not, can this scheme be easily modified to allow for PID?

If that guide can be tweaked a bit to allow for PID, that may be the best easy option - parts list and all included.
 
renatoa
Nope, MAX6675 is not easier, and the readings are not precise enough for an usable RoR estimation. MAX31855 brings no improvement in this respect.

Check my TC4ESP fork project, for the maximum precision and features you can get today for less than $30 in electronic parts with a DIY solution.

MAX31855 is only a temperature sensor, roasting is more than that, it's about taking decisions.

PID is not the best method to control a roast, is only a matter of time until you will use manual control, for a lot of reasons.
Edited by renatoa on 04/23/2020 5:43 AM
 
JackH

Quote

renatoa wrote:

Nope, MAX6675 is not easier, and the readings are not precise enough for an usable RoR estimation. MAX31855 brings no improvement in this respect.


Do you really need that kind of precision for coffee roasting?
---Jack

KKTO Roaster.
 
JackH
Welcome to Homeroasters Mtbizzle.

You have researched and organized your roaster project well.
---Jack

KKTO Roaster.
 
renatoa

Quote

JackH wrote:

Do you really need that kind of precision for coffee roasting?


Depends what others mean by easier when comparing a MAX based solution versus TC4, as asked OP.
Numbers of wire to solder for connection? numbers of code lines to see something on display? cheaper?

Home coffee roasting can be as fun and easy, or as exacting and technical, as you want to make it.
Some can have stellar results using a stove/pan roaster, like Hive, others seems lost without an Artisan and strings attached.
According to some people pickiness, even Artisan didn't delivered a good RoR estimation until a code change in V1.3, so there is always room for improvement.
All depends what are the OP goals.
Edited by renatoa on 04/23/2020 8:32 AM
 
mtbizzle

Quote

renatoa wrote:

Check my TC4ESP fork project, for the maximum precision and features you can get today for less than $30 in electronic parts with a DIY solution.

PID is not the best method to control a roast, is only a matter of time until you will use manual control, for a lot of reasons.


Thanks, Renatoa! I just spent some time looking at your project. It sounds great to me. It would actually save me quite a bit of $. As it is, I was going to buy a cheap laptop to run Artisan, but this would allow Bluetooth or wifi - a major advantage for me, in addition to what you already said.

As you were talking about what is meant by easier -- the issue is just that I have very little experience coding, soldering, etc. I can follow instructions very well, but my ability to be able to troubleshoot will probably amount to asking others.

A few questions to start --
* looking at your schematics. It sounds like you would recommend the TC4ESP-ZCD_bb schematic as the most up-to-date one that includes all of the features mentioned?

* Could some of these connections (eg from chip to chip) be made using breadboards? I think doing so would reduce my chance of errors, so I'm going to try that where possible. I imagine it would make things very easy if most of it could be arranged on a few breadboards - would make mounting easy too. Grin

* Where are the temp probes in the schema? IO3?

* Any guidance on what temp probes to use would be helpful. My plan is to use a popper, and to have one probe just above the heating vents in the chamber

-- sort of like this? i.imgur.com/DvoyFjU.jpg (I think i would place probe farther in).

Would this RTD sensor be a great option? https://www.adafruit.com/product/3984 IDK whether it would be beneficial to add a second temp probe for a popper setup. Have never seen anyone discuss BT ET probe placement for a popper.

* You mentioned an eBay order/shopping list - that would be awesome to have! My goal here would be to try to replicate what you have written up as closely as I can.

* Last but not least - this should all be compatible with a popper - just a matter of wiring this circuit to the heating circuit?

Big thank you to all!
Edited by mtbizzle on 04/23/2020 1:47 PM
 
renatoa
Yes, breadboard can be used, every board in this setup is using the standard 2.5mm pitch pins for connections.

Probes are connected at the input(s) of AD 849x TC amps, K-type TC only supported atm.
IO3 is the Arduino name of an output pin, for PWM control, unused in my design, but supporting/inheriting all TC4 associate code.

Just updated cost analysis document on github with an eBay source that stocks atm almost all components.

Will update next days the sources to the last (supposed) stable version I have, probably faster than the time is needed for your order to travel from China.

RTD is not supported by TC4 code, only thermocouples.
Is not very complicate to add RTD support, but I can't test the code, just post as-is.

I think is better to discuss further TC4ESP specifics in the thread dedicated to this project in data-loggers section of this forum.
Edited by renatoa on 04/23/2020 2:06 PM
 
Phil Mc1stCracken
Thinking about doing something very similar. Can't seem to find more details on building my own TC4, but looking to take my roasting past the way-too-fast-and-hot popper stage to something a little more-controlled. Might as well tag along and see how your project goes! :)
 
mtbizzle

Quote

Phil Mc1stCracken wrote:

Thinking about doing something very similar. Can't seem to find more details on building my own TC4, but looking to take my roasting past the way-too-fast-and-hot popper stage to something a little more-controlled. Might as well tag along and see how your project goes! :)


Check out Renatoa's build, and also this thread: Track this thread Print ThreadTC4+ Arduino coffee roaster shield (TC4-compatible)
Roast: Nostalgia popper
Grind: Bunn G3, Comandante c40
Brew: aeropress, v60, la pavoni professional & flair espresso, Hoffmann french press, 'Scott Rao' water
Ask me about Tea!
 
renatoa
For a popper you over-complicate the whole thing with tethering computer controlled roasting, especially based on the illusory BT reading.
Some food for thinking:
- the FB patriarch of this forum, oldgearhead RIP, used a constant power strategy, no touching heater knob, changing only airflow during the whole process
- the +1000$ Ikawa glossy popper machine roast using air temp measurement only
- why and how is this possible, you could find a an approach in the thread titled "well tempered roaster".

I know, is uncertainty of obtaining good results, and need to rely on numbers to justify the decisions... but, as already said, roasting is more about senses, and less technology.
Edited by renatoa on 05/04/2020 2:24 AM
 
mtbizzle

Quote

For a popper you over-complicate the whole thing with tethering computer controlled roasting, especially based on the illusory BT reading.

- the +1000$ Ikawa glossy popper machine roast using air temp measurement only


Are you suggesting that it would be a good idea to roast ET PID in a popper? Would ET be pre-roasting chamber, near where the air passes to the roast chamber, or high up in the chamber, above the beans?
Roast: Nostalgia popper
Grind: Bunn G3, Comandante c40
Brew: aeropress, v60, la pavoni professional & flair espresso, Hoffmann french press, 'Scott Rao' water
Ask me about Tea!
 
renatoa
Please.,. search in the past, it was been over discussed, with various arguments for over and under the plate probe location.
ET in this context is E from environmental, hot air that perform the roast, not E from exhaust, i.e. above the beans.

And no, no PID as control, constant PWM or ICC would ensure a much stable temperature, imo.
By PID I mean an industrial on-off PID, not the theory and associated control method.
 
mtbizzle
What do you monitor and how do you determine your profiles for your popper Renatoa?

Quote

Please.,. search in the past, it was been over discussed, with various arguments for over and under the plate probe location.


I'm having trouble finding these discussions! Has it been discussed before in detail for poppers?
Edited by mtbizzle on 05/05/2020 1:21 AM
Roast: Nostalgia popper
Grind: Bunn G3, Comandante c40
Brew: aeropress, v60, la pavoni professional & flair espresso, Hoffmann french press, 'Scott Rao' water
Ask me about Tea!
 
pisanoal

Quote

mtbizzle wrote:

What do you monitor and how do you determine your profiles for your popper Renatoa?

Quote

Please.,. search in the past, it was been over discussed, with various arguments for over and under the plate probe location.


I'm having trouble finding these discussions! Has it been discussed before in detail for poppers?



There are several discussions that could be found by searching something like "ET probe placement" and looking at the hits on this forum.

The main discussions are:
1. Under the perf plate (heated air before it enters roast chamber)
2. Just over perf plate (immersed in the bean mass, but seeing mostly hot air temperature that is in contact with the beans prior to most of the heat transfer)
3. Hot air leaving roast chamber (exhaust temperature rather then "environmental temp" as renatoa alluded to). (see discussions on adding a temp probe to Fresh Roast systems).

Do the search for more detailed discussion on how people feel each method works for control in various scenarios.
 
mg512
In my experience, any probe placement works well enough, as long as it's consistent. I wouldn't worry too much about this as a beginner. (That's not to say that it's not something that can't be fine-tuned once you're up and running and get a feel for what's happening.)
 
https://www.tindie.com/products/15798/
mtbizzle
MG512, did you keep your probe placement as it is in the inscrutable guide (one a few mm above vents in chamber, and one pre-roast chamber near heat)?

cdn.instructables.com/FLC/SPNW/JW4TKCHV/FLCSPNWJW4TKCHV.LARGE.jpg

If you kept same placement, how do you end up using the information? E.g., does one of the temp numbers seem to correlate passably well with "true BT" for the purposes of timing roast stages, and is one of them more useful for fan/heat control?

I'm obviously very beginner, so am trying to learn all of this as I go pouring
Roast: Nostalgia popper
Grind: Bunn G3, Comandante c40
Brew: aeropress, v60, la pavoni professional & flair espresso, Hoffmann french press, 'Scott Rao' water
Ask me about Tea!
 
mg512
Oh, is the guide "inscrutable"? I tried to be as clear as possible. If there's anything that's not easily understandable, let me know what!

I kept them there, yes. I experimented with different probes and placements inside the roast chamber for "BT", but qualitatively they made no significant difference. With any of them, following a background profile recorded with the same probe and location (or following a manually designed profile twice) led to near-identical (to my taste) roasted coffee (with the same green beans, obviously). On the other hand, background profiles don't transfer well if you alter probe placement even a tiny bit. I've always used "BT" inside the roast chamber for heat control (with fan constant), so can't say much regarding ET.

It's true that with fluid-bed roasters you don't really get the true bean temperature, as your probe will always also measure the hot air going through the beans. (I imagine this is also true in drum roasters, just to a much smaller relative extent.) But, in my experience, it doesn't matter that much for the same reason as probe placement doesn't matter too much: It's less important what you measure, and more important that you measure the same thing consistently and reproducibly.

And again, that's not to say that there isn't always room for improvement.
 
https://www.tindie.com/products/15798/
mtbizzle

Quote

mg512 wrote:

Oh, is the guide "inscrutable"? I tried to be as clear as possible. If there's anything that's not easily understandable, let me know what!


Haha! Instructable guide -- autocorrect got me.

Thanks for reply. I've been trying to read up on probe placement, I'll do what you did and try to secure the probes well in place to try to reduce movement.
Roast: Nostalgia popper
Grind: Bunn G3, Comandante c40
Brew: aeropress, v60, la pavoni professional & flair espresso, Hoffmann french press, 'Scott Rao' water
Ask me about Tea!
 
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