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snwcmpr
08/18/2019 4:31 AM
Awesome I sent an email to AllenB and JackH The email to JackH failed. I had screenshots of my settings.

allenb
08/18/2019 3:37 AM
Jack and I are enlisting help from our PHP site admin to try and solve as soon as possible. Thanks for letting us know.

snwcmpr
08/18/2019 2:53 AM
I got another PM last night......... No email notice.

snwcmpr
08/17/2019 7:36 AM
Email address correct. I constantly check junk folder. I turned off, then on, the setting to receive notice.

JackH
08/17/2019 7:10 AM
Also check that there are no spam filters set for email.

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Fully Integrated ESP32 Coffee Roast Controller
BenKeith
I see exactly where you are coming from but I'm from the old school of try not to put all your eggs in one basket. A catastrophic failure means the whole system has to be replaced. Component systems, while still mounted all in one case, means only the failed section has to be replaced. On the outside of the box, everything can still look and connect the same, Inside the box, you have several components doing the job instead of one.
Now, don't get me wrong, I admire what you have done, and your knowledge is light years beyond mine. When I first got my associates degree in electronics back in the early 70's they were still teaching tubes and I was building tube type amps. When I go my EE in the late 70's I was still working on 50's era tube radios in Italy. Then other than piddle stuff I do as a hobby, I've been out of electronics for over 20 years. So what does all that mean? I'm a total dumbass when it comes to modern day electronics. That's why you see most of the stuff I do is old school, and avoid SMD's when all possible, with my old eyes, I can't see them dang little components.
 
greencardigan
Would it be able to also switch SSRs? Or would I have to use the on-board triacs?

The reason I ask is that I am currently switching 3 SSRs. Two SSRs are connected to my 1st AC circuit (powering my blower and one element) and the other SSR is on a separate AC circuit (powering 2 more elements).
 
BenKeith
Nope, it's totally integrated for internal control. If the TC4 will drive two SSR's in parallel, another pin could added at the input of the optocoupler, but I don't know if you could drive two from one output without adding a something like a 2N3904 transistor driver. Which this would be easy enough to do, I was thinking about adding a couple of LEDs so you can see the pulse rates of the triacs.

I will tell you what though, if the contraption works as planned, I can add another whole section so it will drive three for you. I'm thinking the parts to build it won't be too expensive, but I might be thinking wrong when I start ordering them. Would you be able to come up with a spare pin to drive the third one or would I have to parallel the one input for the heater. I also hope my mouth ain't overloading my butt because the weather is starting to get where I can get back on several outdoor projects I have going and my indoor time is getting limited. This kind of stuff comes down to a couple of hours at night.
Edited by BenKeith on 03/08/2018 10:29 PM
 
ahardinger
greencardigan wrote:

Would it be able to also switch SSRs? Or would I have to use the on-board triacs?

The reason I ask is that I am currently switching 3 SSRs. Two SSRs are connected to my 1st AC circuit (powering my blower and one element) and the other SSR is on a separate AC circuit (powering 2 more elements).


The espEspresso, I think I like that name, has two open drain outputs so you can definitely run additional SSR's. Each output can sink around 500mA so you can parallel multiple SSRs on each output if you wanted to. Or run relays or hook up a DC fan to cool heatsinks, etc...

So you could wire the first circuit into the espEspresso, and connect the blower and 1st heater element to its internal SSR outputs. Then run two wires over to the external SSR which is fed from your second circuit and power the other two heater elements.

Also, the firmware is setup allowing you to "map" control value ranges to output value ranges. So you could "stack" and scale the internal and external heater elements. Allowing for load sharing/balancing etc...

For example, you want to draw up to 1000 watts from the circuit connected to the internal SSR and then a full 4000 watts from the circuit connected to the external SSR. You could tell the controller that Heater1 (Internal) is mapped from 0%-25% over the control range of 0-100% and that Heater 2(External) is mapped from 0%-100% over the control range of 0-100%.

In practice then, you command 50% heater power (2500w). Heater 1 (internal) Duty Cycle = 12.5% (500w), Heater 2 (External) Duty Cycle=50%(2000w). You command 100% power (5000w), Heater 1 = 25%(1000w), and Heater 2= 100% (4000w).

Or you can stack them like they're staged. Map Heater 1 (0-25%) to Input Range 0-20%. Map Heater 2 (0-100%) to Input Range (20-100%).

It plays out like this: Command 20% Power (1000w/5000w), Heater 1 Duty=25% (1000 watts), Heater 2 Duty=0%. Command 50% power (2500w/5000w), Heater 1 Duty=25% (1000 Watts), Heater 2 Duty = 37.5% (1500w).

So, I guess the short answer is; it will do what you want.

-Aaron
 
allenb
BenKeith wrote:

Nope, it's totally integrated for internal control. If the TC4 will drive two SSR's in parallel, another pin could added at the input of the optocoupler, but I don't know if you could drive two from one output without adding a something like a 2N3904 transistor driver. Which this would be easy enough to do, I was thinking about adding a couple of LEDs so you can see the pulse rates of the triacs.

I will tell you what though, if the contraption works as planned, I can add another whole section so it will drive three for you. I'm thinking the parts to build it won't be too expensive, but I might be thinking wrong when I start ordering them. Would you be able to come up with a spare pin to drive the third one or would I have to parallel the one input for the heater. I also hope my mouth ain't overloading my butt because the weather is starting to get where I can get back on several outdoor projects I have going and my indoor time is getting limited. This kind of stuff comes down to a couple of hours at night.


Ben,

For the sake of common forum etiquette, post a thread for your project and allow Aaron's to stay focused on his project.

As we all know , starting an alternate discussion on top of someone else's thread distracts and also causes both topics to get lost with no way to find them.

Thanks,

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
ahardinger
New boards came in. All previous known bugs are fixed and it's so much nicer to program now with a legit USB Bridge IC in place. No floating pins and no uncontrolled action while booting up.

Got everything up and running and did a roast, a light Ethiopian dry process, and it turned out great. Ended up not saving the profile in artisan on accident! =(

Anyways, one thing did happen. An esd event to the thermocouple reset the board. I realized then that I didn't have a lick of EMI/EMC filtering on those pins so I'm going to turn a PCB one more time. Before I do that however I want to see if anyone out there has any suggestions on hardware changes before I do. I'm attaching the Schematic and Layout here as images. I'm just lazy and haven't setup the git repository yet. If anyone has eagle and wants the design files send me a PM.
ahardinger attached the following images:
topsoldermask.png top_copper.png bottomcopper.png component_placement.png schematicsmaller.png

Edited by ahardinger on 03/12/2018 9:46 PM
 
ahardinger
A lot of the circuit is actually for EMC/EMI compliance, high voltage safety, and general ruggedness. Things like using two 1210 resistors in series is because the each single resistor is only rated for ~200VDC and this board is capable of 240VAC operation. Traces are sized for 20+ Amps.

Trace separation and clearances between AC Conductors is providing FUNCTIONAL INSULATION only, and even then only up to ~1500V. The separation is 1.5mm.

The isolation between the HV and LV sides is much better @ 7.7mm which SHOULD provide ~5kV of safety isolation. This board hasn't been tested at any lab and I make no claims about it's safety. Approach this will caution and use your judgement to determine what's safe for you!

I'm slammed with work at the moment so this project is getting very little of my time right now. But if you have any questions let me know and I'll try and answer them in a timely manner.

-Aaron
Edited by ahardinger on 03/12/2018 9:45 PM
 
greencardigan
Sounds great!

So the header labelled HEATER2 is where an external SSR could be connected?

What about inputs like the TC4 uses to allow it to be used standalone. The TC4 supports two potentiometers to control blower and heater levels, and up to four digital inputs.

How easy is IC1 to solder? Is a QFN28 doable using hot air reflow?
 
ahardinger
greencardigan wrote:

Sounds great!

So the header labelled HEATER2 is where an external SSR could be connected?


Yes, that's an open drain output with a +5v source pin so you can wire it to an external SSR without any fuss.


What about inputs like the TC4 uses to allow it to be used standalone. The TC4 supports two potentiometers to control blower and heater levels, and up to four digital inputs.


I was thinking that it would have to be over the external i2c buss. I've got a weird tick where I need to make my layouts efficient... plus I was being lazy. Either way, here is the new layout with a 14-pin header that gives these capabilities on-board!

4 Switches supported, each input pin has a pull-up and a GND pin next to it so you can directly wire N.O. switches without any additional splices etc...

2 Potentiometers connected to ADC channels on the ESP32. Again, there are V+ and GND pins provided on the connector so you can hookup a pot without any fuss.

Take a look at the copper for the pin out. All inputs are ESD/EMI/EMC protected and filtered so robust design is preserved. The board got ~7.5mm wider though...


How easy is IC1 to solder? Is a QFN28 doable using hot air reflow?


Initially I use a hot plate from Walmart, solder paste, a stencil, and a steady hand. If I need to rework it then a hot air rework station does a fine job. When using paste make sure its high quality and fresh otherwise QFN can be problematic. Hot air, use lots of flux... You don't need paste to solder this with hot air. Just get enough solder on the pads, apply flux, and heat. Give the part a tap once the solder is molten and it should center up and clear any bridges. Its actually not hard at all given some practice.

Everything else can also be hand soldered. The only "fiddly" bits are the diodes... sod523 is SMALL. Not quite as bad as hand soldering 0402 though!
ahardinger attached the following images:
soldermasktopbottom.png schematic.png ui_interfacedetail.png componentplacement.png

Edited by ahardinger on 03/13/2018 12:35 AM
 
mg512
Oh, cool project. I just built a controller for my espresso machine based on the ESP32, and was thinking of doing a roaster controller around it as well. Guess you were faster! ;)

Regarding triac on board vs separate high-voltage board: I had a similar desire to not have too many different PCBs involved with my current TC4-based board; In my case I had to have a separate 24V DC PSU anyway as I'm using a DC fan. So I put a DC regulator onto my board to convert the 24V to 5V to power the arduino, along with a transistor to drive the 24V DC fan via PWM. This way my hardware is reduced to Arduino + TC4-like shield, DC PSU, and one SSR. Of course with AC fans the situation is different.

Just to check my understanding, you still need a zero-cross detection circuit to drive an AC fan with the on-board TRIAC, correct?
 
https://www.tindie.com/products/15798/
renatoa
Is this board powerful enough to be the brain of a similar controller as yours, but modular ?

https://www.bangg...92733.html

I.e. to run the code without major changes...
DIY: TO based IR to bean 750g
Moded commercial: Dieckmann RoestMeister, Nesco, popcorn.
TC4ESP, PID controllers, MS6514 USB/Artisan/Apps
Grinder: MBK Feldgrind, mod'ed Porlex to 47 conical burrs, vintage PeDe Dienes
 
ahardinger
mg512 wrote:
Just to check my understanding, you still need a zero-cross detection circuit to drive an AC fan with the on-board TRIAC, correct?


Yes, but that's also integrated into this design.

Nice on the espresso machine controller. The esp32 is pretty awesome!!!
 
ahardinger
renatoa wrote:

Is this board powerful enough to be the brain of a similar controller as yours, but modular ?

https://www.bangg...92733.html

I.e. to run the code without major changes...


That looks like it's based on the esp8266 chipset. They don't share the same code base but it would be easier than porting arduino code over. The low level HAL would need to be rewritten, and I'm not sure they have the same hardware peripherals.
 
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