Tweaking values for reader

[daniguerrero]

Hi,
thanks for setting up this project. I'm trying to get the reader working using Raspberry PI 3 Model B+ and a cheap 433Mhz receptor connected to it. Station H13726.
I can see data gpio changes values when reading it, but running reader provides no output, I guess I need to tweak SEPARATOR_LENGTH, ONE_LENGTH or LENGTHS_MARGIN, however Im not sure what would be good values to try, is there any proper method to getting those values that would work for me?

[yu55]

Hi @daniguerrero

Oh yes, you definitely must tweak those constants because your Pi is much faster than mine.
Try adding simple printf log printing level variable to standard output (check line int level = digitalRead(RECIEVE_PIN);), run program for 3 minutes, redirect stdout to a text file and than search for patterns in this file. Patterns should look something like "00000000000111110000000011111111111111000(...)". A nice long sequences of repeated zeros and ones. These patterns represent impulses from the actual radio transmission received from weather station. Most of file content will be just random noise "01010110101010010010101010101". You must visually search for transmission in this noise scrolling file content in your favorite notepad. It's really fun :) And you definitely should spot a transmission - if you are really receiving it. I had lots of problems with range and noise when using cheap receiver. When you will finally find the transmission just measure how long the impulses are (count zeros and ones by each impulse) and tweak constants according to what you have found.
Thanks for visiting my project. Leave a star If you like it ;)
Have fun :)
Greetings

[daniguerrero]

read_values.txt
Hi @yu55, thanks for your quick response, I've captured attached reading and I'm trying to find the pattern. Actually I was wrong and the raspberry pi Im using atm is Model B Revision 2.0 (revision 000e). I'll give it another try this evening but it might be the case that I have too much noise?. During capture I made sure to place the raspberry pi close to the weather station with direct vision.

[yu55]

@daniguerrero So your Pi is exactly the same as mine. Below is output from cpuinfo on my Pi:

$ cat /proc/cpuinfo 
processor	: 0
model name	: ARMv6-compatible processor rev 7 (v6l)
BogoMIPS	: 697.95
Features	: half thumb fastmult vfp edsp java tls 
CPU implementer	: 0x41
CPU architecture: 7
CPU variant	: 0x0
CPU part	: 0xb76
CPU revision	: 7

Hardware	: BCM2708
Revision	: 000e
Serial		: 0000000077476b93

So auriol_reader should work out of the box without changing the constants.
I looked inside your file - I don't see any transmissions there.
Is your Pi doing other CPU intensive tasks? If it's under heavy CPU load or handling lot's of interrupts, the reader application will not be able to actually sample the antenna signal in fast and regular pace because of not enough free and stable processing power from the CPU.
Are you sure that weather station is transmitting? Are batteries OK?
Also receiver might be a problem. Distance between station and receiver is one thing but also positioning of antennas is important (e.g. one antenna vertical vs other horizontal may not work). Maybe try to change the room where you're working.
Also cheap receivers have low sensitivity (and low quality in general) - this is why I bought more expensive but much more sensitive AUREL RX-4MM5++/F receiver. And it works much better.
You must experiment. There is not much more I can help, unfortunately.

[daniguerrero]

So it seems several issues are happening at the same time, I tried using another raspberry pi I had around and reinstalling from scratch wiringPi also put together on a board transmission and reception module connected to pi and for some reason this brings much more cleaner data, I tried approaching a remote from the garage and it is indeed reading its values. Now the trouble is that it seems those cheap modules don't have enough sensitivity to get remote signals (Im using XY-MK-5V), I will try attaching a 16.5 cm antenna to see if that makes any difference and if that doesn't work I will just get a better receptor module. How's the AUREL RX-4MM5++/F receiver? does it receive data across walls?. The head display that came with the weather station receives data just fine across some walls.
Thanks!

[yu55]

Great job. Keep it coming! :)
I don't think XY-MK-5V can work without at least simple wire antenna? But I might be wrong here... I always used antennas with my receivers. First a simple wire and then switched to antenna dedicated for external usage (antenna used to increase automatic gates receivers range). This dedicated antenna has long antenna cable so my Pi is inside house and antenna is outside. I didn't tested AUREL RX-4MM5++/F through walls. But outside range was like 3 times greater than XY-MK-5V.

[daniguerrero]

Adding a simple wire as antenna actually makes a difference :), but it still needs to be close to the weather station to receive something, now at least it seems Im getting Rain values, but that might be coming from the rain unit?. I still need to come up with better antenna or receptor though. And also find out if what orientation should have the antenna on the receptor. Attaching last capture.
read_values.txt

[yu55]

Good job @daniguerrero!
Yes, rain values are only from the rain unit.
I think sooner or later you will come to conclusion that a good quality, sensitive receiver is needed.