IR sensor heating


Howard Dutton
 

On Thu, Jan 16, 2020 at 05:29 AM, koal01 wrote:
i have a basic question for you, can i use the 12 V- wire (from the wind sensor) for another purpose and use the 5V- instead ? can the wind sensor work with a 12V+ and 5V- ? Since all the negative wires are connected together it should be possible ?
I don't have a schematic to see what exactly you have wired to what but generally speaking yes a common ground can be run on one wire.


koal01
 

Thank you for your answers.
The option of using a relay is interesting even manually and easy to implement
In my research how to save one wire (to connect the relay). i have a basic question for you, can i use the 12 V- wire (from the wind sensor) for another purpose and use the 5V- instead ? can the wind sensor work with a 12V+ and 5V- ? Since all the negative wires are connected together it should be possible ?

Koal01


Howard Dutton
 

I really don't experience these issues with my cloud detector, guess climate has a role or perhaps the sensor in an small insulating plastic housing helps.

Did you try to set the heater to a low level just a few degrees of temperature rise (like in the 1 to 5°C range)?


Howard Dutton
 

On Thu, Jan 16, 2020 at 03:28 AM, koal01 wrote:
Do you thinnk using relay could be used with a kind of temperature ( and humidity ?) threshold in order to open the current only when it's needed ?
Obviously one could add a little MCU to control a relay/heater.


koal01
 

Hi Howard,
Do you thinnk using relay could be used with a kind of temperature ( and humidity ?) threshold in order to open the current only when it's needed ?
Last night heating seemed to having helped IR working constantly all night long, i'm afraid one minute heating every hour would not be sufficient...
During the day it is different, today it is sunny and the temperature in the box is sqewing the temperature and IR readings.

Last night heating helped the sensor allowing a rapid transition in the middle of the night when the sky has become clearer, usually a change during cold night needs hours to be detected until the morning when the sun removes freeze and humidity 



A bad behavior in a clear sunny day with heating in the weather panel, temperature is  6 degreas higher and humidity is too low.
If OCS could stop the current on the heating, appropriate values would come back

 


Thank you 
Koal01


koal01
 
Edited

i tested 2 hours with the heater stuck on the IR sensor just separated by a plastic piece, readings were not good.
I've just moved the heater sticking it just side by side the component, it gives now a slight heating in the sensor area without perturbating it, since then the readings are more reliable.
I'll need a few days to confirm that it's better espcially when the conditions are extreme keeping an eye on values of course.

Using a relay would be so nice of course but my 8 wires are used :
2 wires used for sla and slc i2c interface (humidity, pressure, temperature,  sqm, ir)
2 wires for 5v+ and 5- (humidity, pressure, temperature, sqm, ir, rain)
2 wires used for 12 v+ and 12 v- (wind)
2 wires for analogic pins  (wind and rain)

I'll need to pull a new cable. If you want to test relay and prepare some code i'll be pleased to test.

A sreenshot of what occurred since i implemented the heater, when i stuck it on the component the values changes about 10 degrees lower, i had to intervene a second time to adjust its position.



Koal01


Howard Dutton
 

You don't need a switch to turn the heater on/off... could just use an OCS relay.  If you do that one could even get fancy and, for example, heat for one minute every hour and block taking readings during that time if that tends to keep the sensor clear.


Howard Dutton
 
Edited

You should test Sky IR temperature with the heater ON and with the heater OFF then compare to see if heating the sensor disturbs the readings.


koal01
 

I'm testing a way to protect IR sensor from bad weathers (rain, humidity, freeze) to keep the lens as dry as possible.
Some times bad conditions can affect and skew its sensitivity.
Here are some screenshots indoor and outdoor, today weather is cool and dry (around 12 °C)

1- As we can see the heater indoor can rise to a high level


2- A measure on the glass of the lens (indoor)


3-Now outside, as shown the heater ensures goog warm, in this test all the components are totally outside, inside a box the protection would be better

 

4- outside with the multimeter directly on the lens, the temperature is maintained to a good level


Hope it will help, i plan to use this heater (5v/1w bought from Aliexpress) with a toggle switch i would set to off during summer an on during winter.

Koal01