• Post Reply Bookmark Topic Watch Topic
  • New Topic
permaculture forums growies critters building homesteading energy monies living kitchen purity ungarbage community wilderness fiber arts art permaculture artisans regional education experiences global resources the cider press projects digital market permies.com all forums
this forum made possible by our volunteer staff, including ...
master stewards:
  • Nicole Alderman
  • raven ranson
  • Jocelyn Campbell
  • Julia Winter
stewards:
  • paul wheaton
  • Burra Maluca
  • Devaka Cooray
garden masters:
  • Anne Miller
  • Pearl Sutton
  • Joylynn Hardesty
  • Shawn Klassen-Koop
gardeners:
  • Joseph Lofthouse
  • Bill Crim
  • Mike Jay

Using Arduino and temp sensors for RMH metrics  RSS feed

 
Posts: 20
1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Hey All,
I'm getting closer to building my first RMH and I'd like to embed some temperature sensors in the heat riser, mass and exit flu.  For the mass and exit flu I'll use the common sensor the DS18b20.  But for the heat riser will require a beefier sensor; a K-Type.  I've been shopping around looking for something that can sense up to 1100C but haven't found one I like.

Has anyone out there done this?  Looking for recommendations.

Thanks
Rich
 
Posts: 26
Location: Western central Illinois
10
hunting trees wood heat
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
I would look around on Amazon. Something like this might work;
Perfect-Prime TL1813 K-Type Sensor Probes Metal HeadProbe for K-Type Probe Thermocouple Sensor & Meter in Temperature Range from 0 to 1000 °C http://www.amazon.com/dp/B0142SDKC0/ref=cm_sw_r_cp_apa_i_.nA5Bb2S7BHCH

I am doing something similar on my build, but I'm just using sensors on the wall under the heat shielding to monitor that.
Adafruit and Sparkfun are my go to sites when starting an Arduino project. For components, Newark, Mouser, and DigiKey are hard to beat. McMaster Carr might have some options as well.
 
Posts: 363
Location: Derbyshire, UK
18
cat chicken urban
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Not for a RMH, but for kilns I've used K-type thermocouples and a raspberry pi. My kiln only reached 600C so not quite as hot- but it worked well (probably still would but I haven't used the kiln for a while!).

I used a wire-type thermocouple and I think its limit was 800C or so. But the same brand has ones that claim up to 1100C. ie: https://uk.rs-online.com/web/p/thermocouples/3971264/

For the electronics I used a MAX6675 thermocouple amplifier and an ADC, if I remember correctly.
 
Rich Points
Posts: 20
1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Thanks for the recommendations Caleb and Charli.

So a couple of more questions. 

I'm thinking of placing this near the top of the heat riser by drilling a hole in the fire brick and cobbing it in place.  My guess is it's best to have the entire probe exposed to the heat source; so a short one, 2 -3 inches.  Another option would be to attach it directly to the barrel above the heat riser; not sure how i'd do that.

Whichever way I chose the next question becomes how do I run the wire?  As far as I can tell, but not verified, the wire is rated to the temp of the sensor itself.  My thought is to run it down the outside of my ceramic blanket and hold it in place with cob/slip.  And then exit the cob on the backside below the bell/barrel.  Then I need to get the wires to an amplifier like this one and then to an Arduino, I'll be using a Feather Huzzah with OLED display LCD display.

I want to keep the wires as short as possible but the Arduino needs to be a safe distance away from the heat source.

Anyway, that's the direction I'm heading with this. 

Any and all feedback is appreciated.

Gratitude
Rich
 
Caleb Mayfield
Posts: 26
Location: Western central Illinois
10
hunting trees wood heat
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator
Aside from the wire not carrying the same heat rating as the probe, I think you are on the right path. Embedding it on the outside of the riser would be the way to go for a permanent install. Just remember that insulation does not stop the heat, it just slows it down.

One question I have is what specifically are you trying to measure in the riser? The reason I ask is that the temperature will be different at different heights within the riser, so if there is a specific piece of information you are after it may determine where the sensor should go.
If you are looking to log the data points for heat riser exit temps I would go with a sensor that goes through the top of your drum and sticks directly down into the center of the exhaust column.
Or, if you are trying to get readings at various heights you could attach the probe to a tube and drop it down the riser under full burn to collect a series of readings.
 
Rich Points
Posts: 20
1
  • Likes 1
  • Mark post as helpful
  • send pies
  • Quote
  • Report post to moderator

One question I have is what specifically are you trying to measure in the riser?


I'm just trying to get a sense of the heater I build, it's not a scientific inquiry per se.  It's my understanding that the top of the heat riser will see the hottest temperatures. 

Our land has Maple, Oak, Poplar and White and Red Pine.  It'll be cool to know what temps these various woods burn. 

by the way this is the sensor and amplifier I ordered

https://www.amazon.com/gp/product/B009HW44F4/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

https://www.amazon.com/gp/product/B00SK8NDAI/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1

Anyway the parts are in the mail.  Can't wait to get it wired up and coded.

My stove build is still weeks/months out but I'll have this ready to go!

Thanks!
Rich
 
No holds barred. And no bars holed. Except this tiny ad:
One million tiny ads for $25
https://permies.com/t/94684/million-tiny-ads
  • Post Reply Bookmark Topic Watch Topic
  • New Topic
Boost this thread!