Two DHT22 Temp / Humidity Sensors?

D

downerhouse

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I've just added a second DHT22 so that I can measure the lounge temperature / humidity as well as the same in my sump, and no matter what I do, Robo Tank does not recognise the 2nd sensor. If I unplug the original sensor and plug in the new one, it works just fine on the original port, so I know it is not a dodgy sensor or wiring.

I've tried a different sensor port, as well as swapping over the black jumper for a different one, and nothing gets the 2nd sensor to work.

Any suggestions please?
 
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Actually, quick update. I've just realised it's a bug in the dashboard (or would appear to be). The current status dashboard icon shows a "NAN" error, whilst the actual graph is updating correctly. See attached picture.
 

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Rob F said:
Sorry about that, I'll have to look into it.
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Hi Rob

In addition, the graphs report some very odd values. If you take a look at the screen dump, the temperature graphs are all over the place. In the UK, we've had a really warm April, and yet the value reported at 6am today was -1.5 degrees C! Yesterday was a really warm day (26 degrees C), and the temperature was reported around 12-13 degrees C. I can't really fathom what is happening, and can't comment on the humidity levels.

But it seems that the dashboard summary (current reading that only shows 1 of the sensors working) the values do not tally with the graph readout.
 

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downerhouse said:
Hi Rob

In addition, the graphs report some very odd values. If you take a look at the screen dump, the temperature graphs are all over the place. In the UK, we've had a really warm April, and yet the value reported at 6am today was -1.5 degrees C! Yesterday was a really warm day (26 degrees C), and the temperature was reported around 12-13 degrees C. I can't really fathom what is happening, and can't comment on the humidity levels.

But it seems that the dashboard summary (current reading that only shows 1 of the sensors working) the values do not tally with the graph readout.
Click to expand...
Hi @downerhouse I wonder if that's related to the NAN issue on the home page or possibly timing between the two sensors. Can you disable one of them on the "Configure Ports" screen and let only one run to see if it clears up. I've had a DHT22 running months without issues but timing during a read is very important, it was an issue when I was setting up. I'm wondering if both sensors are being immediately read back to back causing the issue, I've never tried two sensors. When reading those sensors the GPIO is polled many times with delays between, if this is off readings can be out of whack.
 
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Hi Rob

I've disabled one - the odd thing then was that it still appeared on the dashboard, until I changed the type back to float sensor. Anyway, only now got one enabled, and yes the summary / graph is correct now (for now at least!).
 
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downerhouse said:
Hi Rob

I've disabled one - the odd thing then was that it still appeared on the dashboard, until I changed the type back to float sensor. Anyway, only now got one enabled, and yes the summary / graph is correct now (for now at least!).
Click to expand...
Sorry for my absence. Is the graph still showing correct data, it's looking like it's related to the other issue.
 
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