iDRY Vacuum Kilns

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Kiln temp and humidity logger using the Raspberry Pi platform

Started by btulloh, December 31, 2017, 02:05:44 PM

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btulloh

HM126

btulloh

Hard to read.  Oh well.  Just a bunch of numbers and timestamps.  Trying to adhere to the FF "post more pictures" rule.
HM126

Crusarius


btulloh

It can be put into a csv file instead of going to the screen.  Probably better to put in a database and let SQL handle the overhead. 

Basically the data can be anything you need it to be.
HM126

Crusarius

thats great if you know SQL. I dislike it and it hates me :)

However, I am a master with excel.

ChugiakTinkerer

 smiley_clapping

Looking good!

Meanwhile, back at the CT ranch, I'm still waiting for my goodies to ship.

For those reading unfamiliar with the CSV format, it's simply a text file with values separated by commas, hence the file extension abbreviation: Comma Separated Values.
Woodland Mills HM130

btulloh

It can be done any way that suits you.  That's the good thing about doing this.  I'm not adept in SQL either but I can pick my way through a simple thing like this.  I think it's the easiest way (for me) to get data stored, then put up into the cloud, and then retrieve it.  Then I'll put it into Excel too to use it.  It's just personal preference.  I think it will be the easiest and quickest way for me to get to the ultimate goal.  I may also be wrong about that.  :D
HM126

Crusarius

google drive and google sheets may be something worth looking into for that? Or maybe java? I forgot you want to view it on a website.

btulloh

Those too. 

These days there are many ways to skin this particular cat.  I guess that's the  good news.  At some point it comes down to grabbing a weapon and joining the battle.  But when it's time for the battle, you need have picked out your weapon.
HM126

GeneWengert-WoodDoc

If you want a formula for calculation of RH from DB and WB, see
http://maxwellsci.com/print/rjaset/v6-2984-2987.pdf

If you want formula EMC values, see the Wood Handbook (2010 edition), equation 4.5.

For a complete table, see DRYING HARDWOOD LUMBER, about page 15.
Gene - Author of articles in Sawmill & Woodlot and books: Drying Hardwood Lumber; VA Tech Solar Kiln; Sawing Edging & Trimming Hardwood Lumber. And more

btulloh

Thanks Doctor Gene, that's very helpful.  The document you reference is directly relevant to this task.  Now we have the info needed.  That makes this a productive day!!
HM126

btulloh

Starting to work on the data file and cloud storage today.  The more I look at alternatives and work on the implementation I'm starting to think that a simple CSV format will be the better solution.  It will become more clear as the work progresses.

Interesting Arduino boards with built-in wifi:

https://smile.amazon.com/gp/product/B01IK9GEQG/ref=pe_2518910_267133250_em_1p_6_ti

https://smile.amazon.com/HiLetgo-Internet-Development-Wireless-Micropython/dp/B010O1G1ES/ref=pd_bxgy_328_2?_encoding=UTF8&pd_rd_i=B010O1G1ES&pd_rd_r=6A4555HBFEQNFHBFZAEK&pd_rd_w=ykKCK&pd_rd_wg=evdaz&psc=1&refRID=6A4555HBFEQNFHBFZAEK

HM126

Crusarius

I talked to an electronics guy here at work and he felt that for kiln monitoring the raspberri pi was the best option but for the simpleset I want to do definitely need to do arduino.

btulloh

You're fortunate to have easy access to someone like that.  I don't think there is a wrong choice.  I wish I had time to get an Arduino and do it BOTH ways.  I've only got another week that I can focus on this before I have to move on to another commitment.  It's gonna take me that long long just to get these particular worms back in the can.  Maybe longer.  Yesterday I should have had 8 hours of undivided attention to this and it turned out to be about 30 minutes.  Today I'm hoping to put more time on it. We'll see.  I have it reading the sensors on a schedule now and I'm working on the data collection and cloud storage.
HM126

Crusarius


ChugiakTinkerer

While I sit on my thumbs waiting for my electronics, I've been thinking about how to house the device.  But for the wifi aspect any old enclosure would work.  One made of steel will kill the radio signal instantly, as will anything that is too conductive.  I suspect any plastic, abs, polypropylene, or fiberglass enclosure will permit enough signal to allow decent data transmission.

I would want it to be big enough to allow mounting a 120v outlet in addition to the RPi and associated circuitry.  I'm visualizing something like the box containing my telephone service entrance, but my google-fu has been weak in finding something that fits my criteria perfectly and doesn't cost $100 plus shipping.  I suspect a visit to the local Re-Store will be fruitful.  Anything weather resistant and roughly 12x12x4 should do the trick.

Assuming the enclosure is mounted on the wall of the kiln, I would run cabling for the sensors though the kiln wall into a waterproof junction box inside the kiln.  If at all possible I would have the junction box inset so that it is nearly flush with the interior kiln wall to minimize opportunities for it to be damaged during loading and unloading.

Once the kiln is loaded, the sensors would be placed either in the stack or on the wall and connected to the junction box with either a mil-spec connector or a trailer/RV connector.  Price and suitability for kiln temperatures would drive that selection.  I can see having three temperature probes set up on a pigtail about 6' long.  One probe would be inserted into a board in the stack.  The other two would be clipped to the wall, with one of the probes having a wick and reservoir for wet bulb temperature.  Just before closing the door the pigtail would be inserted into the socket on the junction box.

One could skip all the junction box and connector mess and just wire the sensors direct to the RPi.  During unloading and loading the sensors could be coiled up hung out of the way on a conveniently placed Velcro strap.  This way would be less costly and less complicated.  But I have no clue which would be better in a given kiln.  I think at the very least there should still be a junction box inside the kiln, for when a sensor needs to be replaced.  If one had to thread a cable through the kiln wall every time a thermistor failed it would probably motivate the owner to put in a junction box anyhow.

Those are my thoughts.  Any of it sound helpful for your existing or future operations?

Woodland Mills HM130

Crusarius

I like a common junction box as a pass through. makes running wires and anything else in and out easy. The real trick is keeping it clean dry and the insulation loss in that area.

Would it make more sense to come through the roof? hanging wires be less likely to get ripped out or damaged if walking around in there.

there are also some mil spec wire connectors that have a ton of leads. that would be the ultimate setup. 1 plug to plug in all the stuff inside the kiln. When not in use unplug and put in storage place. then the only thing you would have to worry about inside the kiln is the plug and the wires.

Search mil spec ip69k connector. gives you lots of options. Make sure if you go this route you specifically find IP69K rated connectors. That is waterproof dustproof all the good stuff.

here is a good reference for IP ratings
https://www.averyweigh-tronix.com/News/news-and-case-studies-by-product/indicators-news-and-case-studies/what-is-the-ip-rating-system/

btulloh

My first thought was to look for a suitable plastic NEMA box.  They even have a few to choose from at HD or Lowes, or any electrical distributor for more choices.  Two plastic conduits through the wall of the kiln from the back of the box which would be mounted on the north wall somewhere.  I plan to mount two temp sensors inside - one in the collector area and one at the outflow of the lumber stack.  Maybe two wb thermo's at the same locations or maybe one wet bulb - TBD.   Put one DHT22 outside for reading ambient t&rH.  The main detail to be worked out is proper isolation/insulation for the relay board on the HV side of things.

Progress:
- Now storing CSV data in a file. 
- Looking around at various free IoT server options for moving data to the cloud.  There are options out there, just trying evaluate and make a choice.  Already signed up for thingspeak.com, but so far not excited about how they work.  Or I haven't found what I'm looking for on their service.

CT - I hope you get your goodies soon.  I have to order some temp sensors and a relay board.  I haven't decided on the best temp sensor to use.  I'm interesting to see you yours does.
HM126

ChugiakTinkerer

Still no joy with Amazon.  I'm headed out to the property for the weekend.  If it hasn't shipped by Monday I may cancel and go with someone else.

Thanks for the link on the NEMA connectors.  My first thought was that IP69k would be overkill, but the 9k aspect protects against high temperature spray so should hold up to the heat of the kiln.  Right?  say_what
Woodland Mills HM130

Crusarius

That was my thought and the reason for the recommendation. The other reason for that is you can drill a 1/2" hole in the kiln for the wire to pass through and then mount a plate with the connector inside. if you seal the wire it will be very little if any leak helping to keep the kiln better. Then all you need to do is take your full harness and plug in in after all the sensors are located where you want them.

I am all about doing things the easy / lazy way. This will also make wire runs quite a bit cleaner if done right.

btulloh

I'm just going to run some plenum rated cable from the terminal block outside (inside the box with the brain) to the sensors. The sensors will be soldered on.  No connectors.  It's not quite that bad in there - it's not the surface of Venus.  The a/c wiring inside my kiln is EMT and regular duplex outlets and they're doing ok. 

Like the old saying goes: "it's not the heat, it's the humidity".  Plus some noxious gasses from the oak, etc.  I'm going to consider some of those things inside to be consumable.  Heck, the kiln itself only lasts about, 10 years I'm told.

The inside of the kiln is not a neat and tidy environment except for the day you finish building it.  In operation it's never completely closed up either - the vents are cracked open just a bit.  It's supposed to be pretty tight, but not like a submarine.  At one time I thought it should be air-tight to a depth of 20 fathoms, but I learned otherwise.  I guess we build 'em as tight as we can because there still be will be a few air leaks here and there anyway - and then we crack the vents a bit.

Anyway, that's just my approach to the wiring thing.  Low cost, a little bit rock and roll.  Not exactly Mil-spec.  But effective and dependable.  Rev B might be stepped up a little if there needs to be a Rev B.

That's just me.  Everybody builds to suit themselves.  (That's the benefit of my no longer being in the manufacturing biz.)

By the way CT, that seems odd for Amazon.   FYI mine came from Amazon (prime) and they didn't show as SHIPPED until very late the night before they were delivered, on time.   (There is a distribution center here though.)  It seems like the movement between Amazon facilities does not show up in the tracking detail.  Or maybe they just messed yours up.  I hope not.  I'm hoping you get your stuff so you can get started.

===

Not sending data to the cloud yet, but local file writing is doing fine. 

Nosed around on Thinkspeak a little and it may be OK.  TBD

I got sidetracked trying to setup SAMBA on the RPi so I can see it on the Windows network.

HM126

btulloh

Using ThingSpeak.com for cloud storage for now.  Got my application connected and uploading static test data on regular intervals, so that's progress.  I need to hook that process up to the sensor reading process and then I'll have something that is pretty close to the finished deal. 

On another front. the RPi is now able to connect to my Windows network.  I can access network devices from the RPi but so far I can't see the RPi from a Windows machine on the network.  I'm still trying to configure Samba to make that happen, but it's not a major concern at the moment.
HM126

btulloh

Finally got the sensor data going to the cloud in real time.  It's a good milestone.  It's viewable at https://thingspeak.com/channels/398226.
This is just test data, taken from three different t/rH sensors in my home office.  One is room temp, one is the temp of the case opening of the RasPi, and the third is sitting directly over a radiator.  The charts are not very useful - they're just the default charts that come with a new channel page.  They will be replaced with something more useful later.  I have the updates going out pretty rapidly for now, just to speed up the testing process.  I will plan to update the readings every 15 minutes when this is installed in the kiln.

I need to do some housekeeping and cleanup work on the existing code, but it's functioning pretty well at this stage.  It's about time to order some different sensors and start working on the wet-bulb readings.

Thingspeak.com is owned or run by Mathworks, the company that makes Matlab.  I see where they have functions for dewpoint/rh/wetbulb conversions.  These may be of some help in the rH calcs.  To be investigated. 

I have very little experience with Matlab.  Maybe CT, or somebody is fluent in Matlab.  That could be a good thing.

I suppose ChugiakTinkerer is off-grid this weekend.  Maybe his Amazon package will be waiting for him when he returns and he'll get started.

When it warms back up tomorrow I plan to take this RPi outside and test its wifi range.  Hopefully it will be sufficient. 
HM126

Crusarius

looking pretty sweet. I wish I knew more about matlab. all I know is it is installed on my pc at work.

ChugiakTinkerer

Amazon sat on my order for a week, so I just canceled it this morning.  Placed an order with SparkFun for an RPi 3, two DS18B20 waterproof sensors, and a BME280 breakout board for temp/pressure/humidity.

My limited exposure to Matlab was when I was in grad school.  It ran in DOS and needed a math co-processor, which I didn't have.  My advisor had it on his office system, and I have a vague recollection of making some nifty 3D graphs with it.  Something tells me my experience won't be very helpful in this day and age.

We spent the weekend at Lake Louise opening a trail to our property.  Our place is 10 miles from the lodge, and only the first half it had trails established.  So Saturday was spent breaking trail in about 3' of loose snow.  Starting out Saturday morning there was fog on Lake Louise.  I could just make out four caribou, and this is the best I could do with my phone:


 

We broke trail for about 4 hours and got within 1/4 mile of our place and ran into overflow on our lake.  I was able to power through the worst of it and only got stuck in wet frozen snow with thankfully no standing water.  By the time we extricated ourselves the sun was going down so we headed back to the lodge.  I neglected to take any pictures, but this thread on Trapperman shows lake conditions about like mine. https://trapperman.com/forum/ubbthreads.php/topics/4368161/Re:_Advice_on_getting_snowmobi#Post4368161

On Sunday we were able to make it to the property.  I have a temporary structure up, a Hansen Weatherport as shown below.  Everything looked great, no visits from bears or squirrels.


 

Back on topic: SparkFun sent an email confirming my order, so Yay! for modern commerce.
Woodland Mills HM130

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