[AllanG]

Success!!!! A huge "thank you", Werk_AG and uncle_bob.

Last night I thought I had thoroughly checked the hardware, so concentrated for a while on the software. I downloaded it again so I could start with a completely fresh copy, checked the libraries were properly installed and then uploaded to the Nano. Still didn't cure the problem. Before I went to bed I read the posts from both of you and as Werk_AG was certain there could not be anything else in software, I decided it must be a hardware fault, there just couldn't be any other explanation.

I had already checked - several times - that 5v was where it should be and I had also successfully carried out continuity checks to make sure the DHT22 was properly connected to the Nano.

When I thought about uncle_bob's suggestion of disconnecting one side of the 10k resistor R4, I realised it was possible that with the resistor in place, I could have had a false reading when simply checking for continuity. So before lifting one side, I tried removing the flylead with the DH22 connected and first tested from the pcb header to the Nano. All ok. Then, for the first time, I tested the flylead itself without it being connected to the pcb or the DHT22. There was the problem - the terminal pin for the data connection was open circuit!! (Although it appears ok visually, even with a magnifying glass.) Made up a new flylead, connected everything up and it all works. Excellent!!

So my thanks to you both for your patience and continuing support. Me?? Well I feel pretty embarrassed right now (1) for making such a stupid error in the first place and (2) for taking so long to find it...

Right now I'm testing indoors but hope to soon try outdoor tests. Unfortunately it probably won't be this weekend as we have gales forecast from now (winds are already strengthening here) until Sunday afternoon. I'll let you know of course how things progress.

Thanks again.

Allan - an embarrassed but very happy man right now

[werk_ag]

What is important is that it is working now!

It seems that uncle_bob some post above, gave you an important clue:

That looks like a reading where there is actually no reading.

Embarrassed for having done an error? Oh men, I do a lot of them, too! This is the way we learn, isn't it?
Anyway, before powerup, do a careful continuity test on all wires and connections is a good practice. It's easy to forget or left something not wired.

I hope the last part of the building process, will happen with less surprises. In any case, please report.
Thank you.

[AllanG]

You were both a great help, you because you were certain it wasn't a software issue so I could ignore that and uncle_bob for suggesting R4 may be hiding something!

This is a really great project, partly because of the weather station at the end and partly because of the wonderful help and support.

I will report progress soon.

Allan.