Topic: Maplin Solar Weather station N23DQ Humidity reading issue

[thereaper]

Hi all newbie here
for some unknown reason im getting weird humidity readings  keeps dropping to 1%  making the dew point -20 to -45 then it will go back to the correct setting.
 even if is set the correct humidity on the console.sometimes it will stay at the setting for a few hrs then drop to 1%then climb back up jumping  around 20 to 30%  at a time again then go back up  to normal
has the sensor had it!
if so is it replaceable  is it in the heat shield part  as ive had that part looks like a wifi board in there lol or is that a temp/humidity sensor all in one!
Thanks in Advance

 

[thereaper]

heres a pic of it now and its been pouring down all day

[thereaper]

i take it theres no answer for this

[dupreezd]

thereaper, yes the humidity (white part with lines) and temp (black bead) sensors are in the radiation shield. Check to see if the solder joints are good and that there is no water intrusion.

When does it do all this weird jumping, only when it rains?

Yes, it is replaceable, this picture is actually of my old one with a bad hum sensor.
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[thereaper]

hi
thanks for the reply
no it just changes all the time  no rain at the moment and its just gone to 99%  was at 1% earlier this morning very erratic   mine hasnt got the black bead sensor?
will get a pic later

thereaper, yes the humidity (white part with lines) and temp (black bead) sensors are in the radiation shield. Check to see if the solder joints are good and that there is no water intrusion.

When does it do all this weird jumping, only when it rains?

Yes, it is replaceable, this picture is actually of my old one with a bad hum sensor.
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[thereaper]

[dupreezd]

Ok, looks like it is a I2C interface

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and my guess it is a SHT31

[dupreezd]

Is your unit still under warranty?

[thereaper]

no unfortunately

[dupreezd]

Read up on I2C and SHT31. There are plenty examples on the internet as well as replacements. The biggest 'problem' will be to get the address that is currently being used by your sensor.
 

[thereaper]

so we are looking for just replacing this
http://uk.farnell.com/sensirion/sht31-dis-b/humidity-temp-sensor-0-100-rh/dp/2474218RL

Ok, looks like it is a I2C interface

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and my guess it is a SHT31

[dupreezd]

That is just the sensor chip. You are looking for a complete sensor like this.
https://www.adafruit.com/product/2857?gclid=EAIaIQobChMI48Pg4-zR1QIV1bfACh168QSqEAAYASAAEgJjV_D_BwE

[dupreezd]

or this
https://www.seeedstudio.com/Grove-Temperature%26amp%3BHumidity-Sensor-%28SHT31%29-p-2655.html

[thereaper]

can you not just replace the sensor chip i can do micro soldering 

[dupreezd]

i can do micro soldering

then, sure you can. Problem is, what if it is one of the discreet components on the board?

Not many people can do micro soldering.

[thereaper]

well looking at the board theres only one capacitor  i can see .
if it is that,the prob would be getting the same value .if theres a schematic out here  then that wouldnt be a problem.
 

[thereaper]

well looking at the data sheet for the sensor only the capacitor  is a 100nf  will have to test the one thats on the board see wot it reads

[dupreezd]

The actual sensor comes in two options. A bare sensor (the one in the picture you first sent) and one covered with Teflon, like the one you currently have.

[thereaper]

any reason for the teflon cover! cant think wot purpose it has ,maybe heat dispersal

[dupreezd]

lol, not Teflon, PTFE

From Adafruit

Sensiron Temperature/Humidity sensors are some of the finest & highest-accuracy devices you can get. And, finally we have some that have a true I2C interface for easy reading. The SHT31-D sensor has an excellent ±2% relative humidity and ±0.3°C accuracy for most uses. We now use the version with a PTFE filter, it'll stay clean while still allowing humidity measurements to work

[thereaper]

ok quick update  i got the sht31 chip  but didnt even notice the original one is only 6pins  the SHT is 8pins.
now heres my question if you look at pic .1 other side of the pcb  theres pads for 8pin ic does anyone know wot or if the 8pin temp/humidity ic would work on these?

[thereaper]

ok update on this  done a few measurements and the other side of the pcb was live and had the correct voltage for the new one  and will take the 8pin SHT31 digi humidity/temp senor
so ive taken the 6pin one off  and the smoothing capacitor .
resoldered the cap on the other side and soldered the new SHT31 ic  on the board.(dont attemp this if youv never done micro soldering as the new ic will only withstand 350 degrees for 6 seconds before you kill it)
sorry pic a little out of focus as it wouldnt zoom in that close as its so small.there was no need to reprogramme the address for it  to work.pic 2 is off the old one
the SHT31 digi  is supposed to be a lot more accurate and stable than the original ic
so its been running acouple of hrs now and all seems fine nice and stable