Re: [PLUG] Temperature recorder

[Paul Heinlein]

On Fri, 12 Aug 2022, Rich Shepard wrote:


On Thu, 11 Aug 2022, Keith Lofstrom wrote:


Maybe not; I presume roasting coffee beans emit a lot of steam, with a
crazy-varying specific heat compared to room air.


Keith,

It's not steam, but smoke. Heavy smoke. Now I use a 3" corrugated hose (the
type used for clothes dryer exhaust) through a hole in a wood panel set in
the kitchen window. The smoke has attracted neighbors who come over to check
out what I'm doing. :-)


I can attest to the volume of smoke produced during the roasting of 
coffee beans. I roasted beans in very small quantities, and I still 
had to keep the garage door open for anything more than a single 
batch -- even during the Colorado winters.


--
Paul Heinlein
heinl...@madboa.com
45°22'48" N, 122°35'36" W

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Fri, 12 Aug 2022, benjamin knutson wrote:


I think you could just use an arduino or pi pico(which are usually in stock
and can have Wi-Fi). They have data logger shields where you can add an sd
card or if you use esp32 or pico w you can always log to somewhere else.


Thanks, Benjamin.

Rich

Re: [PLUG] Temperature recorder

[benjamin knutson]

I think you could just use an arduino or pi pico(which are usually in stock
and can have Wi-Fi). They have data logger shields where you can add an sd
card or if you use esp32 or pico w you can always log to somewhere else.

On Thu, Aug 11, 2022 at 4:59 PM Rich Shepard 
wrote:

> I've no experience with SBCs while many here have such experience. I want
> to
> build a small temperature recorder that takes input from a thermocouple
> probe, converts the changes to temperature (F and C), and writes the time
> (from start) and temperature to a removable storage device.
>
> There are inexpensive units that do this but the maximum temperature is
> limited to about 150F, and I need a range to 500F.
>
> The use is recording coffee roaster outlet temperatures each second. I'll
> transfer the data to a desktop and plot the rate of rise of the air exiting
> the roasting chamber since I cannot directly measure bean temperature (and
> that's less accurate and meaningful in any case.)
>
> Would an Arduino, Raspberry Pi, or other SBC be appropriate for this? Also,
> suggestions for a sensor module and other components are certainly welcome.
>
> Regards,
>
> Rich
>

Re: [PLUG] Temperature recorder [RESOLVED]

[Rich Shepard]

On Thu, 11 Aug 2022, Rich Shepard wrote:


I've no experience with SBCs while many here have such experience. I want to
build a small temperature recorder that takes input from a thermocouple
probe, converts the changes to temperature (F and C), and writes the time
(from start) and temperature to a removable storage device.


Thanks to another home coffee roaster subscribed to this mail list I no
longer need to take this approach. He pointed me to an Australian article on
using the Gene Cafe roaster that I had not found before. It offers a new
approach to judging roast level using color and oil-ness which is what I've
been doing but by altering temperatures during the roast cycle which I've
not done. Much less expensive and time consuming. :-)

Thanks very much, Russell, Tomas, and Keith. And especially Bruce.

Regards,

Rich

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Keith Lofstrom wrote:


Maybe not; I presume roasting coffee beans emit a lot of steam, with a
crazy-varying specific heat compared to room air.


Keith,

It's not steam, but smoke. Heavy smoke. Now I use a 3" corrugated hose (the
type used for clothes dryer exhaust) through a hole in a wood panel set in
the kitchen window. The smoke has attracted neighbors who come over to check
out what I'm doing. :-)

Regards,

Rich

Re: [PLUG] Temperature recorder

[Keith Lofstrom]

On Thu, Aug 11, 2022 at 01:59:18PM -0700, Rich Shepard wrote:
> There are inexpensive units that do this but the maximum temperature is
> limited to about 150F, and I need a range to 500F.

As a cheap wildass alternative, can you use a second
controllable fan to mix room air with your roasting
chamber output air, aim the output mix setpoint at
150F (or whatever) with a thermostat, then estimate
temperature from the mix ratio and physical gas laws? 

This kludge would require calibration (use dried peas,
cheaper than coffee beans?), but you could implement
it with cheap hardware store tech and calibrate it
with algebra and a Rubber Bible.

Maybe not; I presume roasting coffee beans emit a lot
of steam, with a crazy-varying specific heat compared
to room air. 

Which implies that an electronic sensor must be
steam-resistant; very hot steam is corrosive.  It also
suggests that your roasting set point (for whatever kind
of controller) should also adjust to moisture content for
different kinds of coffee bean.  Roast temperature is a
proxy for output product, perhaps you will discover a
better proxy.

But maybe, after enough cups of coffee, you can invent
a cheap fix, perhaps invent a profitable product.  You
aren't the only customer who cares beans about coffee.

Keith

-- 
Keith Lofstrom  kei...@keithl.com

Re: [PLUG] Temperature recorder

[Russell Senior]

If you can locate the laptop within 5 meters of USB cable run from the
microcontroller, then you can get immediate information over USB from
the microcontroller, and potentially control the process, using
something easy to develop on. For example, you could program the
microcontroller to measure the temperatures over SPI from the RTD
amplifier, and print ASCII to a tty over USB on your laptop, which you
could just log or read with python to do something more sophisticated.
There is a fair chance someone has done all of this already and you
can find a howto somewhere on the internet.

Finding the Raspberry Pi Zero W for sale today might be way harder.
Before the chip shortage, they were $10 + shipping. Looks like they
are going for $35-$50 on ebay.  I'm holding on to mine until they hit
$200.

For microcontrollers, I am a fan of the PJRC Teensy's. The creator of
the Teensy is a local. The LC would be completely adequate for doing
the SPI/Serial translation: https://www.pjrc.com/store/teensylc.html

On Thu, Aug 11, 2022 at 4:01 PM Rich Shepard  wrote:
>
> On Thu, 11 Aug 2022, Russell Senior wrote:
>
> > How often do you roast, and can you afford to dedicate a laptop to the
> > process during roasting times?
>
> Russell,
>
> Generally once per week. Yes, I can put my laptop on the stove top (it's
> off) when I'm roasting. Would this allow an Ethernet or USB connection that
> would be easier to implement than wifi?
>
> Rich

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Tomas Kuchta wrote:


I hope that I am not distracting from the HW. With my question.


Tomas,

Nah.


How do you plan to implement temperature control loop? You intend to
control the temperature, correct?

I am asking because - What would be the point of measuring temperature
every few seconds - if not for the perfect roast. I hope that I am not nosy.


For a Full City roast (approx. 440-445F) in the GeneCafe CBR-101 the company
recommends setting the roaster's temperature to 482F (250C) and cooking each
batch for 19 minutes.

Each coffee farm (or cooperative), each country and region within a country,
and each year's crop from them varies greatly, Just like wines from
different terroirs. My preference is for roasted beans that have a heavy
body, full mouthfeel, and moderate acidity so I go for a Full City or Full
City+ roast. How the green beans are processed (naturally dried, washed, or
otherwise) and the water content of the green beans (target is generally
11.5%) dictates how the beans roast.

By measuring the outlet air temperature at small time intervals, and
plotting time vs temperature produces what's called a Rate of Rise (RoR) for
that bean. The curve tends to start high, dip to an inflection point (when
most water has been evaporated), then rises to two indicators (first and
second crack) which indicate how the bean chemistry (it's volatile organic
compounds) have changed. I'm still learning how to interpret the curves to
generate the outcome I want.

Of course, grind size and brewing method also affect the flavor and feel of
what you drink in the mug/cup.

IMO, the effort is worth it, as is preparing all my foods from scratch.

Stay healthy,

Rich

Re: [PLUG] Temperature recorder

[Tomas Kuchta]

On Thu, Aug 11, 2022, 19:01 Rich Shepard  wrote:

> On Thu, 11 Aug 2022, Russell Senior wrote:
>
> > How often do you roast, and can you afford to dedicate a laptop to the
> > process during roasting times?
>
> Russell,
>
> Generally once per week. Yes, I can put my laptop on the stove top (it's
> off) when I'm roasting. Would this allow an Ethernet or USB connection that
> would be easier to implement than wifi?
>
> Rich
>
.


I hope that I am not distracting from the HW. With my question.

How do you plan to implement temperature control loop? You intend to
control the temperature, correct?

I am asking because - What would be the point of measuring temperature
every few seconds - if not for the perfect roast. I hope that I am not nosy.

Thanks, Tomas

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Russell Senior wrote:


How often do you roast, and can you afford to dedicate a laptop to the
process during roasting times?


Russell,

Generally once per week. Yes, I can put my laptop on the stove top (it's
off) when I'm roasting. Would this allow an Ethernet or USB connection that
would be easier to implement than wifi?

Rich

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Russell Senior wrote:


A raspberry pi zero w can do wifi. Or an ESP32 or ESP8266 as well.
Programming the microcontrollers is likely to be more challenging for
novices. requiring an investment of time learning how to make your stuff
work.


Russell,

Then I'll buy a raspberry pi zero w, a case and USB power supply for it, the
adafruit PT1000 sensor. Does the RasPi zero w come with an SPI?

Rich

Re: [PLUG] Temperature recorder

[Russell Senior]

How often do you roast, and can you afford to dedicate a laptop to the
process during roasting times?

On Thu, Aug 11, 2022 at 3:17 PM Rich Shepard  wrote:
>
> On Thu, 11 Aug 2022, Russell Senior wrote:
>
> > I'd recommend not messing with local storage, but immediately forward
> > it to a real computer, either over USB or a network, if you possibly
> > can.
>
> Okay. Wireless would be needed because the roaster is in the kitchen and
> computers are in my office.
>
> Rich

Re: [PLUG] Temperature recorder

[Russell Senior]

A raspberry pi zero w can do wifi. Or an ESP32 or ESP8266 as well.
Programming the microcontrollers is likely to be more challenging for
novices. requiring an investment of time learning how to make your
stuff work.

On Thu, Aug 11, 2022 at 3:17 PM Rich Shepard  wrote:
>
> On Thu, 11 Aug 2022, Russell Senior wrote:
>
> > I'd recommend not messing with local storage, but immediately forward
> > it to a real computer, either over USB or a network, if you possibly
> > can.
>
> Okay. Wireless would be needed because the roaster is in the kitchen and
> computers are in my office.
>
> Rich

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Rich Shepard wrote:


This page says they have 63 in stock.


Oops! 

Rich

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Bill Barry wrote:


If you want to sample the temperature that quickly make sure you get a
very tiny thermocouple otherwise its mass will keep it from responding on
1 second time scales.


Bill,

My research (not terribly extensive) finds web sites that relate to
commercial roasters, not us home roasters. But, I saw that 3 second
intervals will work, too. And if that's good for the multi-kilogram
commercial roasters it's certainly good enough for me. :-)

Thanks,

Rich

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Russell Senior wrote:


I'd recommend not messing with local storage, but immediately forward
it to a real computer, either over USB or a network, if you possibly
can.


Okay. Wireless would be needed because the roaster is in the kitchen and
computers are in my office.

Rich

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Russell Senior wrote:


This sensor might do the trick: https://www.adafruit.com/product/3984


Russell,

Well! I missed that one. Its range is -50°C to 280°C.


Connected to this: https://www.adafruit.com/product/3648 (out of stock!)


This page says they have 63 in stock.


Connected over SPI to a microcontroller or a RasPi.


SPI recommendation? Arduino model recommadation? Data storage connection and
programming language? (I've not see the latter two on their web site.)

Thanks,

Rich

Re: [PLUG] Temperature recorder

[Russell Senior]

I'd recommend not messing with local storage, but immediately forward
it to a real computer, either over USB or a network, if you possibly
can.

On Thu, Aug 11, 2022 at 3:06 PM Rich Shepard  wrote:
>
> On Thu, 11 Aug 2022, Russell Senior wrote:
>
> > The worldwide supply of raspberry pi's available through ordinary retail
> > channels is zero right now (or was the last I looked). But they'd be a
> > good choice.
>
> Russell,
>
> Huh! Part of the computer chip shortage?
>
> > The missing information is "how far away is your coffee roaster?" If you
> > are close enough, you could use a microcontroller like an arduino or
> > similar and interface with the sensor of your choice directly to a PC over
> > USB. Your range with USB is usually 5 meters.
>
> I want a small unit (an arduino would be fine) that sits next to the roaster
> and stores data on an SD card, USB drive, or similar storage device.
>
> > I don't know very much about measuring temperatures up to 500F, I am
> > mostly interested in air temps and related phenomena. Look on some place
> > like adafruit.com for a sensor and how to interface with it.
>
> There seem to be availble probes but finding a sensor to which the probe
> connects that works with an arduino or raspberry pi has been a challenge.
>
> The adafruit.com web site has a probe/sensor with a maximum temperature of
> 125F and I didn't see a 'contact us' link where I could ask about a higher
> temperature sensor.
>
> Thanks,
>
> Rich
>

Re: [PLUG] Temperature recorder

[Rich Shepard]

On Thu, 11 Aug 2022, Russell Senior wrote:


The worldwide supply of raspberry pi's available through ordinary retail
channels is zero right now (or was the last I looked). But they'd be a
good choice.


Russell,

Huh! Part of the computer chip shortage?


The missing information is "how far away is your coffee roaster?" If you
are close enough, you could use a microcontroller like an arduino or
similar and interface with the sensor of your choice directly to a PC over
USB. Your range with USB is usually 5 meters.


I want a small unit (an arduino would be fine) that sits next to the roaster
and stores data on an SD card, USB drive, or similar storage device.


I don't know very much about measuring temperatures up to 500F, I am
mostly interested in air temps and related phenomena. Look on some place
like adafruit.com for a sensor and how to interface with it.


There seem to be availble probes but finding a sensor to which the probe
connects that works with an arduino or raspberry pi has been a challenge.

The adafruit.com web site has a probe/sensor with a maximum temperature of
125F and I didn't see a 'contact us' link where I could ask about a higher
temperature sensor.

Thanks,

Rich

Re: [PLUG] Temperature recorder

[Russell Senior]

This sensor might do the trick: https://www.adafruit.com/product/3984
Connected to this: https://www.adafruit.com/product/3648 (out of stock!)
Connected over SPI to a microcontroller or a RasPi.

On Thu, Aug 11, 2022 at 2:50 PM Russell Senior
 wrote:
>
> Oops, lol. Try again.
>
> On Thu, Aug 11, 2022 at 2:44 PM Russell Senior
>  wrote:
> >
> > On Thu, Aug 11, 2022 at 1:59 PM Rich Shepard  
> > wrote:
> > >
> > > I've no experience with SBCs while many here have such experience. I want 
> > > to
> > > build a small temperature recorder that takes input from a thermocouple
> > > probe, converts the changes to temperature (F and C), and writes the time
> > > (from start) and temperature to a removable storage device.
> > >
> > > There are inexpensive units that do this but the maximum temperature is
> > > limited to about 150F, and I need a range to 500F.
> > >
> > > The use is recording coffee roaster outlet temperatures each second. I'll
> > > transfer the data to a desktop and plot the rate of rise of the air 
> > > exiting
> > > the roasting chamber since I cannot directly measure bean temperature (and
> > > that's less accurate and meaningful in any case.)
> > >
> > > Would an Arduino, Raspberry Pi, or other SBC be appropriate for this? 
> > > Also,
> > > suggestions for a sensor module and other components are certainly 
> > > welcome.
>
> The worldwide supply of raspberry pi's available through ordinary
> retail channels is zero right now (or was the last I looked). But
> they'd be a good choice. The missing information is "how far away is
> your coffee roaster?" If you are close enough, you could use a
> microcontroller like an arduino or similar and interface with the
> sensor of your choice directly to a PC over USB. Your range with USB
> is usually 5 meters.
>
> I don't know very much about measuring temperatures up to 500F, I am
> mostly interested in air temps and related phenomena. Look on some
> place like adafruit.com for a sensor and how to interface with it.
>
> --
> Russell

Re: [PLUG] Temperature recorder

[Bill Barry]

On Thu, Aug 11, 2022 at 3:59 PM Rich Shepard  wrote:
>
> I've no experience with SBCs while many here have such experience. I want to
> build a small temperature recorder that takes input from a thermocouple
> probe, converts the changes to temperature (F and C), and writes the time
> (from start) and temperature to a removable storage device.
>
> There are inexpensive units that do this but the maximum temperature is
> limited to about 150F, and I need a range to 500F.
>
> The use is recording coffee roaster outlet temperatures each second. I'll

If you want to sample the temperature that quickly make sure you get a
very tiny thermocouple otherwise its mass will keep it from responding
on 1 second time scales.

Bill

Re: [PLUG] Temperature recorder

[Russell Senior]

Oops, lol. Try again.

On Thu, Aug 11, 2022 at 2:44 PM Russell Senior
 wrote:
>
> On Thu, Aug 11, 2022 at 1:59 PM Rich Shepard  wrote:
> >
> > I've no experience with SBCs while many here have such experience. I want to
> > build a small temperature recorder that takes input from a thermocouple
> > probe, converts the changes to temperature (F and C), and writes the time
> > (from start) and temperature to a removable storage device.
> >
> > There are inexpensive units that do this but the maximum temperature is
> > limited to about 150F, and I need a range to 500F.
> >
> > The use is recording coffee roaster outlet temperatures each second. I'll
> > transfer the data to a desktop and plot the rate of rise of the air exiting
> > the roasting chamber since I cannot directly measure bean temperature (and
> > that's less accurate and meaningful in any case.)
> >
> > Would an Arduino, Raspberry Pi, or other SBC be appropriate for this? Also,
> > suggestions for a sensor module and other components are certainly welcome.

The worldwide supply of raspberry pi's available through ordinary
retail channels is zero right now (or was the last I looked). But
they'd be a good choice. The missing information is "how far away is
your coffee roaster?" If you are close enough, you could use a
microcontroller like an arduino or similar and interface with the
sensor of your choice directly to a PC over USB. Your range with USB
is usually 5 meters.

I don't know very much about measuring temperatures up to 500F, I am
mostly interested in air temps and related phenomena. Look on some
place like adafruit.com for a sensor and how to interface with it.

-- 
Russell

Re: [PLUG] Temperature recorder

[Russell Senior]

On Thu, Aug 11, 2022 at 1:59 PM Rich Shepard  wrote:
>
> I've no experience with SBCs while many here have such experience. I want to
> build a small temperature recorder that takes input from a thermocouple
> probe, converts the changes to temperature (F and C), and writes the time
> (from start) and temperature to a removable storage device.
>
> There are inexpensive units that do this but the maximum temperature is
> limited to about 150F, and I need a range to 500F.
>
> The use is recording coffee roaster outlet temperatures each second. I'll
> transfer the data to a desktop and plot the rate of rise of the air exiting
> the roasting chamber since I cannot directly measure bean temperature (and
> that's less accurate and meaningful in any case.)
>
> Would an Arduino, Raspberry Pi, or other SBC be appropriate for this? Also,
> suggestions for a sensor module and other components are certainly welcome.
>
> Regards,
>
> Rich

[PLUG] Temperature recorder

[Rich Shepard]

I've no experience with SBCs while many here have such experience. I want to
build a small temperature recorder that takes input from a thermocouple
probe, converts the changes to temperature (F and C), and writes the time
(from start) and temperature to a removable storage device.

There are inexpensive units that do this but the maximum temperature is
limited to about 150F, and I need a range to 500F.

The use is recording coffee roaster outlet temperatures each second. I'll
transfer the data to a desktop and plot the rate of rise of the air exiting
the roasting chamber since I cannot directly measure bean temperature (and
that's less accurate and meaningful in any case.)

Would an Arduino, Raspberry Pi, or other SBC be appropriate for this? Also,
suggestions for a sensor module and other components are certainly welcome.

Regards,

Rich