More temperature probes!

Request new hardware or ideas for the controller
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Posts: 378
Joined: Mon Oct 24, 2011 7:52 pm
Location: Saint Louis
PostPosted: Wed Jul 03, 2013 12:48 pm
It' s not as simple a solution, but if you upgraded to the RA+ like I did, you can use the original RA to read some extra temps (3) or even pH and sent it to the main over I2C.

-Jon

Posts: 260
Joined: Fri Jul 20, 2012 7:13 am
Location: Oakley, CA
PostPosted: Tue Sep 24, 2013 3:52 pm
Piper wrote:
rimai wrote:Simply by splicing it or creating a simple breakout board that would do the split for you.
I'll put something together for the breakout and change the libs to be able to be initialized with more probes.


So I can put something together on a Veroboard that will split out four or more additional probes and plug that into one of the existing connectors, correct? I know need to update the software too. I want one more probe for to monitor my W/C water so I might as well make room for a few more while I'm at it.

~Charlie


Roberto,

I soldered up a 4-port "temp probe hub" last weekend and plugged it into one of the ports on my RA head unit. I did it mainly as an extension cord for the current probes with the idea that I can add more later when I have time to dig in to the libraries.

I ran into some problems with it though. When I had all three probes plugged into the "hub" the temps would fluctuate up and down a few tenths of a degree every second or two. That was causing the relays for my heaters and fans to repeatedly kick on and off.

Is there anything special I need to do to the libs to get this to work? I thought the changes needed to the libs were only to get the RA to recognize more than 3 probes.

~Charlie

Posts: 260
Joined: Fri Jul 20, 2012 7:13 am
Location: Oakley, CA
PostPosted: Tue Sep 24, 2013 8:46 pm
I might have a bad solder on one of the ports or I possibly neglected to reboot after plugging in the probes. I moved the temp probes around on the hub and rebooted and it seems to be working correctly now.

~Charlie

Posts: 12044
Joined: Fri Mar 18, 2011 6:47 pm
PostPosted: Wed Sep 25, 2013 7:58 am
Nothing on the libs.
You are correct that the change in the libs was neeeded for more than 3 probes support.
Glad you got it working :)
Roberto.

Posts: 260
Joined: Fri Jul 20, 2012 7:13 am
Location: Oakley, CA
PostPosted: Wed Sep 25, 2013 8:20 am
rimai wrote:Glad you got it working :)


It was short lived :/ Within about an hour it was getting all wonky on me again. I'll take a closer look at the board when I get home tonight and make sure I'm not shorting out somewhere and/or didn't cross a wire.

~Charlie

Posts: 260
Joined: Fri Jul 20, 2012 7:13 am
Location: Oakley, CA
PostPosted: Thu Sep 26, 2013 9:02 am
Still no luck with this. All the solders looked good. I also tried it on a breadboard just to make sure and it still gets wonky after about 15 - 45 minutes. The temps only fluctuate 2 - 4 tenths of a degree but it's enough (on my setup at least) to keep triggering the relays.

Is it possible that I'm still having I2C issues on my setup? I suppose I can try unplugging the expansion hub tonight and eliminate all the add-ons to test that.

~Charlie

Posts: 12044
Joined: Fri Mar 18, 2011 6:47 pm
PostPosted: Thu Sep 26, 2013 9:07 am
The temp probes don't use I2C.
They use OneWire.
And I'm taking the fluctuation doesn't happen when the probes are connected straight into the head unit, right?
Roberto.

Posts: 260
Joined: Fri Jul 20, 2012 7:13 am
Location: Oakley, CA
PostPosted: Thu Sep 26, 2013 9:24 am
Correct, no rapid fluctuation when connected directly to the head unit. Just the expected temp fluctuations due to ambient temp. In fact, if I leave just one probe plugged in on the hub it doesn't fluctuate either.

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Joined: Fri Mar 18, 2011 6:47 pm
PostPosted: Thu Sep 26, 2013 9:42 am
Ahhh....
Add a 10K resistor to your hub between VCC and DATA
Roberto.

Posts: 260
Joined: Fri Jul 20, 2012 7:13 am
Location: Oakley, CA
PostPosted: Thu Sep 26, 2013 9:59 am
I just downloaded the Eagle file for the head unit and saw the resistors :) I'll try that tonight and let you know. Thanks!
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