[dorkbotpdx-blabber] Paging the Coffee Roaster

Tue Jul 21 19:46:19 EDT 2009

 **I was going to send the following message directly to Jesse, but I
thought the dorkbot community might find this interesting**

Jesse,
I must apologize for not contacting you earlier. I misplaced the paper with
your e-mail and missed you at the meeting last night. I was doing a little
bit of research for your dad's roasting project. Since my brewing system is
all electric I am less familiar with the automation of gas, but I found some
great information at HomeBrewTalk <http://homebrewtalk.com> and feel
comfortable compiling the information I was able to gather thus far.

*Basics Principle*
The basic principle of automating gas is to open a solenoid valve (main gas
valve) when additional heating is required as monitored through temperature
probes fed into a microcontroller/temperature controller.

*Standing Pilot vs. Intermittent Pilot*
Standing pilots are always lit and will ignite the burner when the main
valve is opened. Intermittent pilots light respond to the call for heat by
creating a spark that lights the pilot light. A flame-sensing rod senses
when the pilot is lit and then opens the main valve and the main burner is
lit. While intermittent pilot systems are more expensive they are safer
because the gas is shut off if the pilot/burner does not light.

To increase the safety of using a standing pilot light one can use a pilot
safety valve. This device has a thermocouple that senses when the pilot is
lit. If the pilot goes out the thermocouple cools and the main valve is
closed. This is not as safe as the intermittent pilot because gas continues
to be fed to an unlit pilot.

*High vs. Low Pressure Gas*
Intermittent pilot systems require natural gas (NG) or low pressure liquid
propane (LP) for their igniter and valve. Low pressure gas systems require
burners with larger orifices and a low pressure propane regulator if using
LP. A benefit of low pressure systems is that one can switch between NG and
low pressure LP with relative ease.

The Brains:
One can either use a standalone temperature/PID controller or build their
own with a microcontroller. If you decide to build your own
microcontroller-based system most of the required code is
readily available on the internet. Another option would be to buy
a temperature/PID controller (available on eBay for ~$40) to use while you
build a microcontroller-based system and then sell the other controller once
you are happy with your own controller.

*Intermittent Pilot Module*--these are additional brains for the systems
that use intermittent pilot lights. This hardware ensures that the pilot
light is lit before the main valve is opened. One could probably incorporate
these functions into a standalone microcontroller system, but it would
require a bit of engineering and testing (and there is a lack of information
on the internet).

*Pilot/Burner Hardware:*
*Standing Pilot (high pressure gas):*
High Pressure LP
Burner<http://www.topfoodservice.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=KECABJ005&Ca%20%20tegory_Code=KECABJ&Product_Count=4>
 $22
Pilot Safety Valve (VASO is common
brand)<http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=pilot+safety+valve&_sacat=See-All-Categories>
 ~75
Gas Solenoid Valve (ASCO and STC are common
brands)<http://shop.ebay.com/items/?_nkw=solenoid+valve+gas&_sacat=0&_trksid=p3286.m270.l1313&_sop=15&_odkw=solenoid+valve&_osacat=0>
 ~25

*Intermittent Pilot (low pressure gas):*
Intermittent Pilot Module (Honeywell
S8610U)<http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=S8610U&_sacat=See-All-Categories>
 ~$50
Intermittent Pilot Dual Automatic Valve (e.g. Honeywell VR8204,
VR8304, ect)<http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=intermittent+pilot+dual+valve&_sacat=See-All-Categories>
~$50-90
*data sheet<http://customer.honeywell.com/techlit/pdf/PackedLit/69-1225.pdf>
the
different valve models
Pilot Burner with Igniter Sensor (e.g. Honeywell
Q345A1321)<http://shop.ebay.com/items/?_nkw=q345a1321&_sacat=0&_trksid=p3286.m270.l1313&_odkw=Pilot+Igniter+Sensor&_osacat=0>
 ~20
*or*
Y8610U Pilot Conversion Kit (Includes all three components above and
wires)<http://www.climatedoctors.com/items/item.aspx?itemid=1176337>
~160
*or eBay <http://shop.ebay.com/?_from=R40&_trksid=m38&_nkw=Y8610U>

Low Pressure Burner<http://www.cpapc.com/store/23-Tip-Round-Nozzle-Jet-Burner-natural-gas-P469C244.aspx>
 $25
11" Water Column (.4 PSI) Propane
Regulator<http://www.lowes.com/lowes/lkn?action=productDetail&productId=88433-2156-F273863&lpage=none>
~$45
(if using propane)

*Common Hardware*:*
*Temperature/PID Controller:*
PID Controller<http://auberins.com/index.php?main_page=product_info&cPath=1&products_id=102>
~$30-70
(Many people like the Auber controllers, but you can get generic PID
controllers from
eBay<http://shop.ebay.com/items/?_nkw=pid+controller&_sacat=0&_trksid=p3286.m270.l1313&_sop=15&_odkw=pid+controller+auber&_osacat=0>
for
less)
Thermocouple <http://auberins.com/index.php?main_page=index&cPath=3> ~10
24VAC Transformer<http://www.goldmine-elec-products.com/prodinfo.asp?number=G12951&variation=>
~$10-20
(You could pick one up at Surplus
Gizmos<http://www.surplusgizmos.com/Transformer-24VCT-4-Amp_p_1423.html>
)

*Microcontroller:*
Arduino-based board (Dorkbord, Diecimila, Sanguino, ect) *Probably a good
idea to think about how many I/O pins will be required to operate the
inputs/outputs before deciding on a board (you can save pins by using a
serial LCD or LED display)
24VAC Transformer<http://www.goldmine-elec-products.com/prodinfo.asp?number=G12951&variation=>
~$10-20
(You could pick one up at Surplus
Gizmos<http://www.surplusgizmos.com/Transformer-24VCT-4-Amp_p_1423.html>
)
Digital temperature sensor(s)
LCD or 7-segment LED display
Buttons
Low power relays to interface with the 24VAC current required by the
intermittent pilot module.

*This hardware if for the intermittent pilot setup. If one wanted to use a
standing pilot they would just need to have a compatible output (perhaps via
a relay) to actuate the solenoid valve.

Resources:
HomeBrewTalk <http://www.homebrewtalk.com>
BrewTroller <http://www.brewtroller.com> -This site is dedicated to an open
source standalone system for automating the process of brewing beer. Since
the process are similar this would be a great resource if you decide to
build a microcontroller-based system.

References:
Brewtus 10 ???? <http://www.homebrewtalk.com/f11/brutus-ten-44403/>
Propane Solenoid Valve
Help<http://www.homebrewtalk.com/f51/propane-solenoid-valve-help-94916/>
B3 1100 Digital Smart
DIY<http://www.homebrewtalk.com/f51/b3-1100-digintal-smart-diy-114187/>
Standing vs. Intermittent Pilot
Lights<http://www.ignitors.com/glossary/pilot-lights.html>

*The attached wiring diagram show how to connect the Y8610U Pilot Conversion
Kit with a PID controller and was posted by Sawdustguy at HomeBrewTalk in B3
1100 Digital Smart
DIY<http://www.homebrewtalk.com/f51/b3-1100-digintal-smart-diy-114187/>

On Tue, Jul 21, 2009 at 1:12 PM, Jesse Mejia <jmejia at tffenterprises.com>wrote:

> The project in question is based on an RK-drum roaster - utilizing a
> gas grill + a motor attached the the rotisserie. Slightly larger scale
> than the little robots or popcorn style roasters - but not as large as
> a commercial roaster obviously. He does it be hand right now - based
> on readings from a thermocouple inside the drum - but he's considering
> automating the gas valves and using some logic to hit certain
> profiles. Seems like it could be fun!
>
> -Jesse
>
>
> On Tue, 21 Jul 2009 13:00:18 -0700
>  Mykle Hansen <mykle at mykle.com> wrote:
> > it seems about five years ago, people were just starting to do
> > interesting
> > DIY instrumentation of small home coffee roasters.  these days,
> > you can buy full-on roast robots with everything built in, and just
> > focus on developing your roasting profile in Excel.
> >
> > i have one of the original FreshRoast popcorn-style roasters,
> > which some people on the internet have hot-rodded with
> > digital thermometers and digitally-controlled variacs in
> > order to automate the roasting.  it's fun and educational.
> >
> > but i eventually noticed that the best coffee roasters
> > seem to do every batch by hand.  =)
> >
> > -m-
> >
> > On Jul 21, 2009, at 11:37 AMTuesday, Jesse Mejia wrote:
> >
> >>
> >> I think I was the one talking about coffee roasting.. it's a project
> >> my dad is thinking about doing. I was at the meeting last night -
> >>but
> >> not for very long.
> >>
> >> -Jesse
> >>
> >> On Mon, 20 Jul 2009 23:12:45 -0700
> >>  Jared Boone <jboone at earfeast.com> wrote:
> >>> On Jul 20, 2009, at 11:09 PM, Sean Green wrote:
> >>>
> >>>> Does anyone have the contact information for the person who was
> >>>> interested in automating the coffee roasting process? I had some
> >>>> information for him, but unfortunately he was not at tonights
> >>>> meeting...
> >>>
> >>> I'm not sure who you're looking for (unless it's me?), but I have an
> >>>
> >>> unhealthy interest in such things. So when you find him, introduce
> >>> me,
> >>> will ya?
> >>>
> >>>     - Jared
> >>>
> >>> _______________________________________________
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> >>
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> > ---
> > HELP!  A Bear is Eating Me!
> > http://helpabeariseatingme.com
> >
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