reef-pi :: An opensource reef tank controller based on Raspberry Pi.

Ernie E

Member
View Badges
Joined
Aug 15, 2019
Messages
16
Reaction score
16
Hey guys,

Has anyone tested the accuracy of the ds18b20 temperature probe? I just got it hooked it up to reef-pi and I'm getting a steady temperature of 76.6F. I have a cheapo digital temperature probe that I've been using for a few months now that is currently reading 79.0.

Discrepancy of 2.4F

Not really sure which one is accurate.
 

Bigtrout

Well-Known Member
View Badges
Joined
Dec 16, 2018
Messages
762
Reaction score
1,929
Hey guys,

Has anyone tested the accuracy of the ds18b20 temperature probe? I just got it hooked it up to reef-pi and I'm getting a steady temperature of 76.6F. I have a cheapo digital temperature probe that I've been using for a few months now that is currently reading 79.0.

Discrepancy of 2.4F

Not really sure which one is accurate.
I had a calibrated temp probe controller that i used to control heaters before reef pi, i tested the ds18b20 DROK probes against it and my 4 ds18b20 were all within .2 degrees of the calibrated probe, and all within .1 degrees of each other.

If you have doubts. Make an ice water bath, see how close each of them read to 32f.
 

Ernie E

Member
View Badges
Joined
Aug 15, 2019
Messages
16
Reaction score
16
I had a calibrated temp probe controller that i used to control heaters before reef pi, i tested the ds18b20 DROK probes against it and my 4 ds18b20 were all within .2 degrees of the calibrated probe, and all within .1 degrees of each other.

If you have doubts. Make an ice water bath, see how close each of them read to 32f.
Just looked up the ice bath technique. Will try that with both of them tomorrow. Thanks!
 

AbjectMaelstroM

Active Member
View Badges
Joined
Jul 21, 2019
Messages
157
Reaction score
174
Location
Richmond
I had a calibrated temp probe controller that i used to control heaters before reef pi, i tested the ds18b20 DROK probes against it and my 4 ds18b20 were all within .2 degrees of the calibrated probe, and all within .1 degrees of each other.

If you have doubts. Make an ice water bath, see how close each of them read to 32f.

That's interesting, I did it this morning, and it seems to work as intended. Confirmed my suspension that one of my probes wasn't as sensitive as the other and took longer to get down to the known temp and still wasn't as on, but still within <0.5F

Screenshot_20190827-063317_Chrome.jpg


Temp1 seems to acclimate faster and is more "accurate" than two. Might have to grab 2 more probes and run two of the best and others as back up.
 
Top Shelf Aquatics

Ernie E

Member
View Badges
Joined
Aug 15, 2019
Messages
16
Reaction score
16
@Ranjib

Hey, not sure if you already know but if have spaces in your device name, telemetry to adafruit spits back a URL not found error and the feed doesn't update.

I had named my temperature probe "Reef Temperature" and while it did initially create the feed on adafruit IO, it never updated it. I then renamed it to "Reef" and the error went away and the updates started passing.

I'm on 2.5 pi3.

On another note: I also tried 3.0 pre-alpha 2 and the PWM hz function wasn't taking. I would update the PI PWM hz setting in the configuration and reload but the setting never updated, so I reverted back to 2.5.
 

tankaholic

Valuable Member
View Badges
Joined
Apr 20, 2015
Messages
2,603
Reaction score
873
Location
Sarasota, FL
Is there a general shopping list available?
I was going to do a build but issues came up but wanting to get this going again
 
OP
Ranjib

Ranjib

Valuable Member
View Badges
Joined
Apr 16, 2016
Messages
6,905
Reaction score
12,105
Location
Palo Alto, Bay Area
@Ranjib

Hey, not sure if you already know but if have spaces in your device name, telemetry to adafruit spits back a URL not found error and the feed doesn't update.

I had named my temperature probe "Reef Temperature" and while it did initially create the feed on adafruit IO, it never updated it. I then renamed it to "Reef" and the error went away and the updates started passing.

I'm on 2.5 pi3.

On another note: I also tried 3.0 pre-alpha 2 and the PWM hz function wasn't taking. I would update the PI PWM hz setting in the configuration and reload but the setting never updated, so I reverted back to 2.5.
The adafruit io issue is a regression. I'll file a bug to track this.
I am yet to pull in the pwm fixes that were shipped in 2.5 to 3.0 branch, so that bug is expected. I'll make sure we have it fixed in next 3.0 prereleases.
Thank you so much for testing and reporting these.
 
OP
Ranjib

Ranjib

Valuable Member
View Badges
Joined
Apr 16, 2016
Messages
6,905
Reaction score
12,105
Location
Palo Alto, Bay Area
OP
Ranjib

Ranjib

Valuable Member
View Badges
Joined
Apr 16, 2016
Messages
6,905
Reaction score
12,105
Location
Palo Alto, Bay Area
I just noticed i have messed up the BOM link during the recent website update. I'll make it visible there.
Darn. I just checked, and most of the items from the list is gone. Not sure if this is due to missing items. Give me some time to consolidate this list again. I have to check first if the links in the individual guides (they are direct amazon links of specific parts) are still intact. If they are, we have to just consolidate them.
 
OP
Ranjib

Ranjib

Valuable Member
View Badges
Joined
Apr 16, 2016
Messages
6,905
Reaction score
12,105
Location
Palo Alto, Bay Area
Talking about 3d printing , I have racked up a decent stock of reef-pi enclosures now :) . In the coming days I plan to improve upon this simple design to make it aesthetically more pleasant and more functional
AB467958-747B-45F6-AC52-5D8BD22DC5A6.jpeg


Next to a set
0EB6AABE-2D36-4CEF-9E77-3BED5D79EB6A.jpeg
 
Top Shelf Aquatics

thoeffe

Member
View Badges
Joined
Oct 6, 2018
Messages
62
Reaction score
16
Can this be done with a raspberry pi 4 and is it expensive? I would love to do an ATO and a doser.
 
OP
Ranjib

Ranjib

Valuable Member
View Badges
Joined
Apr 16, 2016
Messages
6,905
Reaction score
12,105
Location
Palo Alto, Bay Area
Can this be done with a raspberry pi 4 and is it expensive? I would love to do an ATO and a doser.
Yes. Whether it’s expensive or not is but subjective . A simple ato might cost around 20-100$ including sensor, pi, power adapter, WiFi /relay based outlets . Since you can choose individual parts the cost can vary a lot. Pi 4 itself cost 50$ while pi zero is only 10-15$
 
Bulk Reef Supply
Top