I need Relative Humidity, not humidity readings. There is a significant difference, and the sensors don't provide relative humidity. I have asked for help before, and the replies always go "Every temperature sensor has humidity built into it." I can't or won't use the DHT11/22 because they're junk. I need something more dependable.
Here's the best way to describe this: They aren't the same. Relative humidity uses Dew Point and Temperature to determine the percentage of Relative Humidity. I need help determining which sensor can detect dew point and creating the code to do the equation. Please help!
Thanks, Mike
Thank you Tom,
The problem is that the sensor is inaccurate. I've gone through several, and they're junk. I need something that is consistently accurate, and the DHT11/22 aren't. I'm doing research and need dependability. Those aren't dependable. Thanks for replying.
If you are serious about this, you might consider using a pair of DS18B20 temperure sensors as wet and dry bulb thermometers. There is a thread nearby on this matter..
If you are not serious, you use something DHTxx...
Many years ago I designed the electronics for a dew point humidity sensor. Accurate for the time (1% or maybe 2%, I cannot recall).
A gold mirror was chilled until dew formed, which was detected by scattering of light. Gold was used avoid surface contamination. Electronics needed for temperature control and for scattering detection.
All more complex than a 'sensor'.
No problem on that note as long as you are prepared to pay the cost of an accurate sensor. Consider the types and how they work and based on pro & con of each choose a type. You make no mention of an interface. Here are a few good examples from Omega Engineering. I have no idea what your ultimate plan/project is?
Next a good humidity measuring plane requires calibration on a periodic basis. You may want to consider any of several methods and procedures. Years ago I frequently used standardized saturated salt solutions. Up to you how you go about it.
Finally while I have no clue as to your location and any reputable company will have engineering support. I have called Omega Engineering for example and asked to speak to an applications engineer and gotten good help. Again I don't know your application?
Thank you for the info about Omega. Yes, I know it's a little more expensive for a good sensor. Being on location doesn't allow many options like salt sat. I'm using the RH to identify static electricity. Generally it occurs around 20% to 30% RH. There is more to the experiment but as this is a primary control, accuracy and consistency is needed. What sensor do you think would be adequate? I2C type is what I'm leaning towards and I'm going to use a MKR 1010 for Wi-Fi and Bluetooth. I'm trying to figure out how to use the carrier to add more shields. I don't have any experience with the 1010 but it's been suggested along with Arduino cloud. I was told I need to connect the sensors , IOT Arduino Cloud, and I want to add an OLED to see the data in real time as a wearable device. Any assistance would really help a lot. Thanks for reaching out.
OK knowing more now as to your goal. The saturated dalts suggestion was merely for sensor of your choice calibration so you know your numbers are good or can add correction factors.
That said this sensor which uses I2C may be a good candidate less breaking any pocketbooks. Never used one but seems a reasonable solution.
