Upgrading from poor accuracy DHT11 to better accuracy DHT22 temperature humidity sensors

[John JR]

Yet another technical issue to deal with...

I've been using DHT11 temperature/humidity sensors for a while, they're cheap, and they seem to work.

But I really should have taken a better look at the reviews online.

Now I have a bunch of these sensors on different devices in my lab I can see that the humidity readings I'm getting are 32%, 34%, 51%, and 62%.

They're meant to have an accuracy of around 5% but varying from 32% to 62% in the same room, which should have pretty similar humidity everywhere, isn't good enough.

The bad news is I recently ordered 10 of these sensors and that seems like it was a waste of money. I'll need to order more DHT22 sensors which are more expensive but more accurate.

The good news is that it shouldn't take much to update the ventilator and temperature/humidity monitor sketches to support the DHT22 sensor. I'm thinking I'll make the sensor type configurable so the end user can switch between the sensor type in the web based UI.

As for Bob's demo system. I think I'll ship it out with the existing DHT11 sensor, then when a new DHT22 sensor arrives I'll post it. The sensor can then be swapped over which should be a fairly simple task.

I might also have to experiment with a few other types of temperature/humidity sensor to figure out which is the most accurate. Potentially making it possible for the sketch to support a range of different types so end users can choose the one they want to use.

Cheers,

John