Temperature probe for hot tub, or smoker, or sous vide, whatever! rasberry pi

Community Help With My Project
1

total noob, so allow me to say thanks in advance. I’m looking to build a counple controllers that are basiclly the same thing, turn power off and on based on temperatures. I’ve got a couple RPI zero W’s I’d like to use, purchased the relays as well. What are you folks using for a reliable temperature probe? for the hot tub and sous vide it does not need be food safe, but I’d like the option if possible. quick overview of what I’m aiming for:
hot tub control:
control will need to actuate two circulators, one to circulate hot water from the boiler to the heat exchanger, one to circulate water from the tub to the heat exchanger. on a call for heat both circs will run, i was planning on two relays for this. What temperature probe would be best to use? temperatures should be 85-125F i’d think

Cooking control:
I’d like to have a few different temperature probes available, one to monitor the temperature of the cooker ( be it either a water bath like a sous vide, or just the temperature of the smoker) this would control a relay that would cycle a 110v outlet that would power the heat source ( crock pot/rice cooker for most vide style cooking, a fan to stoke the coals on a smoker) . the ability to have some probes to monitor the temperature of the meats would be wonderful. expected temperature range up to 450F or so would be great.

sorry if my format isnt clear, if more info is needed i’m happy to provide!

2

Hey the M, welcome to Cayenne.

I like the waterproof DS18B20 one wire sensors sold on eBay And Amazon in various lengths, they must have a 4.7k pull down resistor installed. Diagrams are here on Cayenne under settings. Since each sensor has a unique identifier there’s no need to program or designate. When you power up, the widgets for each sensor will populate on your dashboard.

Enjoy,
William

3

I’ve used the DS18B20 waterproof for aquarium monitoring and it’s been working great. Let us know how the smoker control turns out, it’s on my list.
Good luck!
Scott

4

Thanks! Got some ds18b20 sensors, gonna give em a go! Any thoughts on a probe more along the line of the thin sharp ones?

5

My only thoughts on sharp would be to scavenge a probe from a digital BBQ Set or like this links below and take a reading on the resistance. If it reads in the proper range for Cayenne setup then add as an analog sensor.

6

Now that summer is here and it’s smoker season I’ll definitely be getting my smoker project out again. As far as meat probes, I was never able to find any on Amazon. Let me know if you find a good one as I’m in the market for one too. I have ordered both of these and had success with them https://www.amazon.com/gp/product/B00899A53G/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B00843IKWK/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 I’ve used both of these to read the values https://www.amazon.com/gp/product/B0100A7SS6/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1 https://www.amazon.com/gp/product/B01LZBBI7D/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1 The MAX31856 definitely seemed to give more consistent results.

7

if it weren’t for such low resistance on the k-type thermocouples there would plenty of options for making a probe from a cheap digital thermometer

8

blockquote, div.yahoo_quoted { margin-left: 0 !important; border-left:1px #715FFA solid !important; padding-left:1ex !important; background-color:white !important; } I should be back on track in the next couple weeks, unfortunately have a couple of other projects in the way! But should be able to feed back on the hot tub part soon!

Marco

1 Like
9

Got some work done tonight! My mind is blown by how much fun this is. Few questions for the more experienced: I’ve added a ds18b20 sensor, it was automatically sensed just as advertised! Awesome! Ok, questions tho…is there a way to add a slider or dial to the dashboard to control outputs? I did add as a trigger, but a dashboard featured control would be amazing.
Does the temperature control operate with a differential at all? In other words, is there a way to just set it to act as a high limit, turn something off at a set point, and have it automatically turn back on after a drop of 2 degrees ( or whatever)? I’m making a controller for a family member who isn’t the …most tech savvy…? And asking him to remember to change both triggers is going to be a task…
Anyway, thanks cayanne! You took me from months of tying to figure out how to code ( not my thing…HVAC controls yes; coding is aaaallll new!) to making magic in a week! I’ll try and keep post updated as I go

1 Like
10

Hi @Marcornantel,

I’m glad you got your project up and running! If you have some time, think you could share your project in the ‘Projects Made with Cayenne’ section?

This is a feature that is in development for improving Cayenne triggers. For right now, unfortunately, will have to remember to change both triggers. [quote=“Marcornantel, post:9, topic:3192”]
Anyway, thanks cayanne! You took me from months of tying to figure out how to code ( not my thing…HVAC controls yes; coding is aaaallll new!) to making magic in a week! I’ll try and keep post updated as I go
[/quote]

Yay :smile: This makes us happy!

-Benny