Best posts made by Stric

At http://www.kandrsmith.org/RJS/Misc/hygrometers.html there is a lot of tests on various hygrometers, like dht22, si7021 etc.

A useful comment if you are measuring quite seldom can be found at;
http://www.kandrsmith.org/RJS/Misc/Hygrometers/dht22_other.html
namely, that upon "measurement" DHT22 actually returns the previous measurement from memory - then actually does a measurement and stores that in memory.
If you poll once per hour, you get one hour old data every time. Poll twice, or poll "often enough".

Please read http://forum.arduino.cc/index.php?topic=54623.0 which basically says that the 3.3v arduino can't read stuff at 115200 baud correctly, things get corrupted due to being unable to get the correct timings. In our tests, semicolon (;) gets corrupted quite often. Unfortunately, the semicolon is "quite useful" in the serial protocol of the Gateway.

Symptoms: Gateway not responding to version checks, gateway not being able to pass on auto-allocated ID's etc.

Solution: Either change clock to 12MHz (hardware mod + software + blah), or just go slower.. 19200 baud seems to work fine for us. Change baud rate in MySensors.h and recompile your serial gateway. Easy-peasy.

V_DESCRIPTION or somesuch, so the nodes can present what each sensor is.. like "DHT Humidity" "DHT temperature" "DS18x20 temperature" "Distance to garage door" "Garage door locked" ... Right now I'm using VAR5.. but..

Using a non-scientific method; looking at the angle of battery discharge graphs over a week, I've noticed that the modules I got from ITEAD are draining batteries at about half the rate compared to an unknown (but probably fake) pretty good module.
ITEAD module; slightly under 1% per day
"other modules"; about 2% per day
This is when measuring and transmitting DHT21 data every minute.

Same card, different box (slightly too small). I cut the LED after taking the picture..

What are you using the high baudrate with? Due to clock frequencies etc, the pro mini can't even generate (actually, read) 115200 baud correctly..

Without further info, it looks like a case of "Doctor, it hurts when I do this" "Well, don't do that then.."

@Pierre-P
That i2c thing is painted and works because it's capacitive (it can even sense when your finger is hovering a millimeter or two away from it, like a capacitive touch screen (your phone)). I put one of them into the soil yesterday. If I remember, I will get back regarding results.. I placed it into the same flower as a resistive fork, with the middle chip (so I have some corrosion).