Arduino humidity sensors: testing and calibration

Three sensors have ability measuring 20-80% RH with accuracy +/-3%
SHT21 and DHT22 are sensors for measuring humidity and temperature.
BME280 is sensor from well-known maker Bosch, for measuring atmosphere pressure, humid and temperature.
This video will show test result of those 3 sensor to check which one is the best one. However, none of them are correctly. We need to calibrate it with simple things.
After make sensor correctly, then we can use it to measure humid and temperature of room, view via internet by Blynk software
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Code and circuit
bit.ly/2KMoryB
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1. BME280 amzn.to/3xTrvzR
2. DHT22 amzn.to/3gNdDjw
3. SHT21 amzn.to/2VKj6hE
4. Arduino UNO amzn.to/3zKAQLV
5. NodeMCU amzn.to/2PPo5e0
6. Humid meter amzn.to/2xURzho
7. Thermometer probe amzn.to/3aIykId
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Other meaning project made by me:
1. Shadow light box bit.ly/2rtcrMN
2. DIY Portable infrared thermometer bit.ly/2M0NOhx
3. Temperature indicator bit.ly/2E5EhBl
4. How to program OLED screen bit.ly/2E7Q5mH
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Thanks for your watching. Please help me to reach 2,000 subscribe! Thanks

[@matts2581]

Fresh work mate! TY for sharing! :)

[@FOATE]

Very very good tip with the saturated NaCl that is the best tip I have ever had regarding humidity sensor calibration. Thank you very much for making this video!

[@engineer2you]

dikke j thanks for your visit :)

[@sylvainmartin73]

instead of using an offset to your measurement use the function map(value, fromLow, fromHigh, toLow, toHigh), it's a arduino built in function. If you had a low datapoint you could use it to calibrate linear data like temperature, humidity, pressure. the salt method is good for getting a high value, there are other salts you can use to get the low datapoint, like the damp rid stuff

[@engineer2you]

Sylvain Martin thanks for your comment. Actually, i used map function at the end of video because offset cant give good result for wide measuring range

[@mostafaal-hajee3055]

How can I use the data map.???

[@engineer2you]

@@mostafaal-hajee3055 hi, you have to build data for "map" function for your own sensor. Watch the video, you will understand how to do :)

[@LarryKapp1]

Thanks - I just put up three sensors outside and they are all different. Now I know how to calibrate.

[@engineer2you]

Glad to hear that!

[@LarryKapp1]

@@engineer2you I showed my sensor setup in a video I just posted - just a quick show of it and video starts at that part th-cam.com/video/ljxi-xDMW7E/w-d-xo.html

[@thanh-gtpham6486]

It's really amazing! Thanks for your good work!

[@HeavyHeavyvich]

It was necessary to multiply, and not use addition. And, it is quite obvious that the correction coefficient will be nonlinear. You should find several points, and for each segment to calculate your correction factor.

[@RP4UXO]

The DHT22 sensors I got all read grossly erroneous humidity values - either 1% or 100%.
The temp readings are OK though.
Has anyone else notice that ?
Is there any solution for those faulty DHT22s ?

[@mariomoreno9954]

ry with water saturated in NaCl (100ml with 36 grs. of NaCl) mix and leave for stabilize, you shoud have a 45 HR between 20 and 60C degree. The problem sometimes is the temperature sensor and as HR is calculated from temperature , that could be the beginning of errors in HR values.

[@aymenbousselmi7949]

Hi sir,i wanted to ask you if linear regression can improve the bme280, have you used for this sensor?

[@engineer2you]

Not yet, friend. But i think it can be

[@afiqharis9552]

may I know, what is the hypothesis of this project?

[@makers_lab]

The humidity sensors use capacitive sensing, so I wonder if the proximity of the devices to each other in the chamber would have an effect. Also, the BME280 is calibrated by the manufacturer and values baked into registers. I'm wondering if these factory calibration values were taken into account in the readings, or whether you used raw values.

[@JavaMike71]

Hi there... I really liked this video. I know its old, but I am trying this method with only BME280 but I get so many errors when trying to upload the code to a ESP32. If you could help, it would be great. I want to use the map function.

[@michelmartins7379]

Thank you for your video 🤜🤛👍😀

[@anllerys]

Thank you!!!

[@TheJaimecasado]

Hi, what will be the Python code for the double map funtion to make the correction. I'm new on this and kind of lost. Bests

[@engineer2you]

Hi, i’m sorry. I dont know much about Python. You can search around to find it.

[@ratbagley]

Well done

[@fpt380]

Thank you ... it was useful ...

[@engineer2you]

Thanks for your comment

[@mostafaal-hajee3055]

I am very interested in calibrating my temperature sensor, but I could not understand, it is difficult for me

[@engineer2you]

mostafa AL-hajee watch it carefully, then you will understand how to do

[@circle4922]

Wow, very nice, thorough work.
So, the hygrometers that people buy at local stores are garbage, and the readings people tell you that they get from them are probably wrong. That's not reassuring at all.
Thanks for this video.

[@engineer2you]

anyway, hygrometers from local store are calibrated by Maker. That's the only way user like us can trust in humid measuring

[@circle4922]

@@engineer2you And they're calibration is often bad, or it goes bad/off in short time.
Thanks.

[@vetrivelrajeswari7498]

Good very useful video.
Thank you.
Sorry sir. I am watched this video too late. (26.09.2022). INDIA .T.N.

[@BorisSiber]

thx

[@singgihpanji]

great.

[@GeorgeJeffin]

Hey, i checked Sodium chloride but my humidity going above 80% why? both sensors showing the same

[@engineer2you]

Just add very little water for Sodium. Use good humidifier for double check, if your sensor result is not correct, let’s offset or calib it

[@GeorgeJeffin]

@@engineer2you I got a industrial hygrometer and one dht22 and one more hygrometer all of them shows humidity above 80

[@engineer2you]

@@GeorgeJeffin haha. What a wierd! All document stated that saturation Chloride will be around 75%. Anyway, let’s think what possible reason could be

[@GeorgeJeffin]

@@engineer2you humidity around my place is 62% is that any problem ?

[@engineer2you]

@@GeorgeJeffin saturated soldium must be in isolated box (seal box), so it will not effected by environment

[@genome692002]

can you also do this with aht10 thanks

[@engineer2you]

Same procedure, you can do it

[@genome692002]

@@engineer2you i would but i dont have a gauge meter.. for now i just calibrated it to online weather data for my area...

[@engineer2you]

@@genome692002 you need another gauge meter (good one) to calib the sensor.

[@LifeGeneralist]

useful video

[@engineer2you]

Thanks

[@mostafaal-hajee3055]

Why not create an educational course on this type of programming? It will be fun

[@engineer2you]

This video is for education. But it seems not fun haha. Sorry about bad editting video