Incorrect readings from RHT03

Other Hardware Sensors
1

I'm trying to use the RHT03 (also known as DHT22) sensor to read temperature and humidity. I'm using the DHT22 library from GitHub - nethoncho/Arduino-DHT22: Arduino library for the DHT22 humidity and temperature sensor, with the lastest revisions 0.5. I'm using this with an Arduino Uno. The library seems to work correctly, but I get erroneous readings:

HT22 Library Demo
Requesting data...Polled to quick
Requesting data...check sum error 1459.10C 37.90%
Requesting data...check sum error 76.70C 37.90%
Requesting data...check sum error 3251.50C 191.60%
Requesting data...check sum error 1356.70C 140.70%
Requesting data...check sum error 1817.50C 3209.50%

I've tried adding the 4.7K pull-up resistor, tried different sensors (AM2302), and tried different pins (digital 7 or 4), but I still get the same results.

I'm guessing this is a timing problem, but without an ocilloscope, I don't know how to work on it further. Could this be a power supply issue? I added a 10uF cap across pins 1 and 4, but that didn't help, either.

Thanks for any suggestions anyone has.

-Kevin

2

I've written a DHT-lib too, maybe try it as alternative?
if both libs fail, the chances are great it is in the wiring?

3

please also try a delay of 2 seconds between readings... (see datasheet)

4

Rob, it's great that you replied, because I was going to post and say, "Nevermind, I switched to robtillaart's library, and it work's just fine now." Thank so much for writing this library. It does exactly what I want.

I always did have the two second delay in the original script, and it didn't help.

Thanks again. Take care.

-Kevin