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Netduino & Hottop
RAG
I'm a newbie and am inspired to learn about remote control because of no TC4 availability and a rather nasty note from someone telling me Hottop control info was proprietary. I'm not much of a hardware guy or a programmer but I have good Google skills and know how to copy and paste. So I begin looking in to what is going on here.

I chose a Netduino because it provides easy programing and debug for the less skilled with the eye on netduino mini for finished product. I've looked at some of the cool stuff on the Google HTC4 project and man their is a lot of cool work there.
The Hottop seems to use digital control for fan and heater so no SSR required but no biggie if it was right?

So I setup .net.
Installed android SDK (got some learning to do there)
Got a bluethooth module (Com1).
A 4x20 (I2C) display.
Omega thermocouples
Max31855 ADC w/ ice point (SPI)

and in no time I'm sending commands to the controller via bluetooth and reading temps. (Still need to figure out the android stuff).

So what's next....
Be sure I've assembled all the links where I learned how to do this in case someone wants a dummies guide to roaster control.
Learn how to program Android and build on the great program someone started there (need to credit all the great work I copied)
Record the built in hottop control of the heater and fan and decide what kinda PWM I want to use.
Look at the work done on I think the Kona project for software PIM integration.
Be sure output is Artisan compatible.
Find out what the consequences are of rerouting Hottop fan and heater control. Current plan is just a remote double pole double throw relay control unless there is something else whacky going on.

Wish I could find the pcb connector and socket for the 8 pin Hottop but not required.

I'll keep and eye on this topic and see if anyone really cares or objects or can provide info or assistance.
 
Dan
Hi, Newbie!

FYI: http://netduino.com/
1 pound electric sample roaster, 3 pound direct-flame roaster, both handmade; modified Mazzer Mini grinder, LaSpaziale Vivaldi II automatic espresso machine. When the electricity goes out I make vacpot coffee from beans ground on my Zassenhaus hand grinder, and heat the water with a teakettle on the gas range.
 
JackH
Hi RAG, and a proper Welcome to the forum!

I don't know much about the Netduino. I know others here have used bluetooth communications and could chime in. It looks like an interesting board. the HotTop lost a really nice TC4 controller and we are hoping it will come back soon.

Are you monitoring two temperature readings (bean and environment)? I ask because it looks like the Max31855 is a single channel.

Jack
---Jack

KKTO Roaster.
 
ginny
Dan:

thanks for taking the time to post to RAG...

-g


no smoking for you today...
 
RAG

Quote

JackH wrote:
........

Are you monitoring two temperature readings (bean and environment)? I ask because it looks like the Max31855 is a single channel.

Jack


I'm using two separate boards sharing SPI bus I got from Adafruit.

The Bluetooth part is getting it to work with an Android app and hoping to build on work from GreenCardigan. This also seems like detailed instructs: here

Right now I'm try to figure out how to communicate with Artisan. I think it expects a three temp string separated by commas but not sure how to configure that app yet to work with the com port.

I like the netduino because visual studio and step debugging is great for the newbie.
 
tiopaeng
This is really good Rag, it will give us more choices in the future. I'm patiently waiting. Keep up the good work and keep sharing.

thanks
Tiopaeng
 
JackH

Quote

RAG wrote:


Right now I'm try to figure out how to communicate with Artisan. I think it expects a three temp string separated by commas but not sure how to configure that app yet to work with the com port.

I like the netduino because visual studio and step debugging is great for the newbie.


You would need to set your baud rate to 19,200 to communicate. that is what Artisan is expecting on the port. N,8,1 (no parity, 8 data, 1 stop bit).

The TC4 only sends information when the Artisan application requests it with a text "read" command followed by a newline (/n). So, you will be getting read/n, requests from Artisan every 2 seconds, (depending on the settings).

The response to Artisan's read command is a comma separated string in logical channel order: ( the TC4 does four channels)
ambient, chan1, chan2, chan3, chan4
So as an example: 75.0,70.5,70.5,70.5,70.5/n would be the response from the TC4.

If you are only using two channels, you can cut down the response and only sent ambient,chan1,chan2/n

I hope this helps, I know you do not have a TC4 but this is what Artisan expects to get so you can try to match for your board.

There is a complete listing of these commands in the TC4 download site:
http://code.googl...n=2&q=

Look at the commands.txt file.

Jack
---Jack

KKTO Roaster.
 
RAG

Quote

JackH wrote:........

There is a complete listing of these commands in the TC4 download site:
http://code.googl...n=2&q=

Look at the commands.txt file.

Jack


Great! Thanks for the help. Got my Bluetooth working with Artisan tonight thanks to cut and paste and the info in commands.txt. The Artisan software allowed me to use my existing com port parameters as well. That is some great software there.
 
RAG
I forgot to mention I started this project in VB but ran into block with << and >> not working and had to use / or * which required help from a friend to figure out. So I switched to { and ;. What the heh, Visual studio does the syntax check anyways and I need to broaden my horizons.
 
RAG
I was just reading about the new do it yourself project (way cool) and I saw in the thread where a guy bought the whole setup already done and good to go with help for the novice for under a $100 from an ebay seller who provided support and delivered the product already programmed. Are you kidding me? Man do I feel more stupid than usual. Well at least I'm learning.
 
Dan
Rag, Those boards on eBay are a good value, especially for hobbyists with more money than time, or who just don't want to mess with electronics. I know I'd buy a pre-soldered unit. I have plenty of hobbies already! The value in buying a kit is lower cost, the joy of making something, and being able to modify it as you assemble the parts. To each their own.
1 pound electric sample roaster, 3 pound direct-flame roaster, both handmade; modified Mazzer Mini grinder, LaSpaziale Vivaldi II automatic espresso machine. When the electricity goes out I make vacpot coffee from beans ground on my Zassenhaus hand grinder, and heat the water with a teakettle on the gas range.
 
RAG
Well I couldn't wait for a Tiny Duino to arrive so decided to mount the thermocouples in the mean time.

What made the thermocouple mount easy was the pricy Omega's and an article on Home-Barista.com where Mike Petro shows his work here

Here is my thermocouple hardware list:
Omega HTTC24-K-116G-2 $25 ea.
Ebay:
GYROLOK THERMOCOUPLE FITTING 1/16 NPT X 2mm STAINLESS *NEW* $3.99 ea
1/16-27 NPT Right Hand Taper Pipe Tap Carbon Steel NEW $3.95 ea.

So because of Mike's article, and the new thermocouple location in the bean mass, I just winged the mount and did not measure. Here are the pics.
RAG attached the following images:
thermo_interal.jpg thermo_back.jpg
 
Dan
Those look good. I use brass compression plumbing fixtures. They work the same, are a tad cheaper, and I can get them at Ace!
1 pound electric sample roaster, 3 pound direct-flame roaster, both handmade; modified Mazzer Mini grinder, LaSpaziale Vivaldi II automatic espresso machine. When the electricity goes out I make vacpot coffee from beans ground on my Zassenhaus hand grinder, and heat the water with a teakettle on the gas range.
 
RAG

Quote

Dan wrote:

Those look good. I use brass compression plumbing fixtures. They work the same, are a tad cheaper, and I can get them at Ace!


There could be problems with unknown ACE brass composition and food but we're not drinking the beans. ACE does not carry 1/16 compression fittings (or nuts) and would charge the same or more than the stainless. These fittings have Teflon sleeves and are intended for this purpose. If you made a mistake and purchased grounded probes, these fittings would also keep them electrically isolated. The bottom line is I like the way they look ;-]

What I found really interesting is the factory probe is in the bean mass.
 
smico
This looks like perfect solution: thin, robust, insulated thermocouples. Most people suggested ET above original probe to the account of beeing farther away from the heaters, so I follow the suite, but it should not make much of a difference anyway,
Thank you for sharing.
Miroslav
Hottop B2 + HTC, Cremina 83, OE Pharos, Brewtus IIIR, Baratza Vario
 
Dan
Yup, I agree they look good. Point of order. I use 3/16" probes, which fit into a 1/4" compression fitting with teflon ferrule. And, everything at ACE is NSF rated for drinking water. But then, considering that beans are dry roasted, that's moot.

hope this helps, Dan
1 pound electric sample roaster, 3 pound direct-flame roaster, both handmade; modified Mazzer Mini grinder, LaSpaziale Vivaldi II automatic espresso machine. When the electricity goes out I make vacpot coffee from beans ground on my Zassenhaus hand grinder, and heat the water with a teakettle on the gas range.
 
RAG
Looking at it I thought the ET probe being higher up, further away from bean tumble, and closer to the heater would give me a more direct reading of the environment temp. But I have no idea and will just have to do a lot of roasting to see how the data works out. (and I am a newbie)

Looking inside this thing and its cost you gotta wonder if a large percentage of the cost went to Lawyers. (IMHO) I'm sure this comment will raise some hairs. Anyways.... It seems to me that the fan doesn't draw air across the bean mass like other setups, but its primary purpose would be cooling the motor compartment and perhaps could draw some air from around the heater shroud. So whats the story with the fan? I read a lot about making your own filter and people worried about changing the air flow and roast characteristics. I don't get it looking inside, unless you're roasting in the snow.

It also appears to me that the factory function of fan setting at 25% steps seems adequate considering it's impact on roast. But this is all just my theory. I realize I do not have a clue, or experience. So what say ye all? I'm about to add the heater and fan control and inquiring minds want to know. Maybe the fan should run backwards.
 
smico

Quote

RAG wrote:
Anyways.... It seems to me that the fan doesn't draw air across the bean mass like other setups, but its primary purpose would be cooling the motor compartment and perhaps could draw some air from around the heater shroud. So whats the story with the fan?
Primary purpose of the fan is to heat the motor up :) But seriously, main function is to evacuate the smoke.
It does draw a bit fo the air across the bean mass, but it has to run at higher speed.

Quote

Maybe the fan should run backwards.

Bingo. Look at extreme mods by Ciel http://forum.home...ad_id=3236
Also new 5000$ Hottop fixes that design flaw.
Hottop B2 + HTC, Cremina 83, OE Pharos, Brewtus IIIR, Baratza Vario
 
RAG

Quote

smico wrote:


Bingo. Look at extreme mods by Ciel http://forum.home...ad_id=3236
Also new 5000$ Hottop fixes that design flaw.


Thank you so much for this info. So I know I will need to incorporate cooling tray fan and motor into my design. May also want to add additional electronics cooling, and make a firewall between roast chamber and motor. I hope ciel-007 provides more info. The QUEST for a better roaster continues. This has made me reevaluate that perhaps I should stop at profile monitoring setup for now, and let the roast control portion of my project percolate.
 
smico
I would say, carry on with profiles as the changes will be tweaking of your old profiles that you will have to do later for other changes of your roaster, like new filter, top filter problem, bigger batches, higher fins in the drum, you name it. I see that you started doing and thinking about modifications early.
Hottop is great roaster and we can do any profile, but everything is on the edge. There is no spare capacity if you run at 100%, except running small batches or using variac.
As for the cooling, I think that exthernal cooler is the best solution. For one, during the cooling there is a heat transfer to the electronics area. I found great design with chaff separation on GCBC, but you have to be a member there to read. Let me know if you are interested and I will dig it up.
Cheers,
Miroslav
Hottop B2 + HTC, Cremina 83, OE Pharos, Brewtus IIIR, Baratza Vario
 
ginny
posts regarding Artisan roast control are:

http://forum.home...post_46047
 
RAG
SMICO, thanks for the info, expertise, and encouragement. Hope we hear more details about the forward air intake setup. Looks pretty good (like the stainless) as well with great insight into some of the problems of redesign.

I wonder about the fin enhancement design. Seems like you'd want perforated fins as well to reduce baking and hotspots. Haven't seen any real discussion of design on that mod as far as bean contact time, time in mass etc. Increase number of small fins vs. adding extensions. Trial and error for the truly obsessed seems the only avenue. Maybe there is some software that could analyze video of colored bean objects and determine an effective solution. Now that is crazy talk....

I logged my first roast today with bluetooth and I now have to hurry and design the control portion as I see room for vast improvement (unfortunately busy for next week). I had purchased the p model by mistake and now I need to add heat percentage vs. on off.

btw. The Artisan bluetooth connection was flaky (terminal session 100% vs. artisan drops erratic) until i reduced the sample interval to 4 sec. As a by product I changed my $5 bluetooth module to have the name of Hottop and changed com from 9600 to 19200 (seemed to have no effect but once less difference with tc4 default)
RAG attached the following image:
sulawesi.png
 
smico
RAG, this looks like very nice roast.
Longer and higher fins are not much discussed here from what I remeber, mostly because Ciel, our local HT mod expert did not implement that modification on his roasters. I hope that at some point he will, and that will be supported with calculations, heat transfer theory and precise measurement of all trials. I love when someone does work for me :)
There were several long discussions on HB, one is here: http://www.home-b...14069.html You can find some nicer implementations there.
I will do mine at some point.
Rama won 1st place on HB home roaster competition with that roaster. He would have won it without it, I am sure. Still, I like the modification.
Hottop B2 + HTC, Cremina 83, OE Pharos, Brewtus IIIR, Baratza Vario
 
RAG
So don't laugh but I installed insulation behind the firewall. This is insulation used in race cars with contact temp well above bean combustion. So I include pics.

I could clearly see the major problem when I got to installing this . Not only is the fan sucking everything into the elecltronics, motor, and plastic enclosure, it is a wide open channel from the bean shoot and chaff tray to the electronics when the bean shoot is open. The design uses a rather large slit instead of a rod and a feeble attempt at reducing the heat intake by adding a shield to the bean drop shoot. Now don't get me wrong, I love the Hottop. I especially love the great instructions on the Hottop web site for replacing any component. But this community is great, and I cant wait to do the 165 and exhaust mods from Ciel's excellent Mod articles to get the mechanics of this unit on the right path. Then it's back to my original intent to add pwm control to the heater and fan.
RAG attached the following images:
firewall2.jpg firewall1.jpg
 
RAG
Got distracted with the firewall Mod and the RAF. Now back to control.

Added the 165F override by Ciel. Put in a DPDT switch to the standard thermocouple that allows me to switch between default and reading the electronics area temp. The added benefit is the switch acts as a forced heater on switch. Obviously not a safe thing to do, but either is roasting.

So I took a look at the fan control. A 90us period (11.1khz) PWM with 15/50/75 duty cycle pulled low for on logic. Heater control was just switched low for on as well. Looks like you can safely just tap right into these lines for controlling the heater and fan. I'll of course verify that before I do, but I have a high level of certainty now.

I'm debating if I still want manual control or if Bluetooth is adequate. In any case, I definitely want default hottop automated control as well as my custom control.

So far so simple. I'm tempted to utilize some existing PID software but not sure there is a need with the nature of the Hottop roasting process. For now just setting up a low frequency ~.5 hz PWM for heater control seem like it would work. Any one care to comment?

Also looking for a part number for the two wire connector used for the fan and built-in thermocouple connectors if anybody knows that.

Thanks
 
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