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Topic: 433 MHz RF - Temperature and humidity sensor (Read 39 times) previous topic - next topic


Code works - the third interrupt gets data. But - again - strange thing happens...
It reads the code only when sensor is very,very near the Mega.
On Uno it read without problems from outside.

I have no clue why it could happen now...

I can only guess the Mega is generating RF noise that interferes badly at 433Mhz. I'm not sure if you could test this by laying the Mega in a biscuit tin lined with something to prevent Mega shorting out and and lay the lid on top. Run the wires to the receiver outside of the tin.  This wont stop all noise but may eliminate radiated RF. Beyond this you may need RF chokes but this is not my field and someone else may have better suggestions.


Feb 23, 2013, 08:10 pm Last Edit: Feb 23, 2013, 08:15 pm by andriej Reason: 1
I got tired of wondering why it didn't work and I wired one of my nodes (used in room anyway) to weather station. Same scheme - DATA (pin2), GND-GND.
It works even better than on the receiver module (as it now gets a lot more readings).

It's getting readings ATM and will do overnight, but before that I saw same-readings with different CRC (only once happened so far):
Code: [Select]
001110100101011000111001001000010 100100110 - Battery=1 Channel=1 Temperature=35.6F Humidity=88%
0011101001010110001110010010000101 00000100 - Battery=1 Channel=1 Temperature=35.6F Humidity=88%

You can see the station and the receiver itself in left top corner here:


Feb 25, 2013, 11:04 am Last Edit: Feb 25, 2013, 11:11 am by andriej Reason: 1
Ok, so after almost all-night logging I've put up to the google doc (at the bottom, below arduino code): https://docs.google.com/document/d/121ZH3omAZsdhFi3GSB-YdnasMjIQSGIcaS7QW6KsACA/edit?usp=sharing
all the values that didn't duplicate one by another (signal is so strong, that your code puts up like 5-6 readings at the time).

Also - strange thing (or we don't know everything). A lot of readings shows 'battery=0', but weather station doesn't report battery as 'low' (the indicator doesnt show up). Maybe the 'low batt' bit is hidden somewhere else?


Thanks for the extra data buy after looking for several readings that only alter by 1 bit in the data (not CRC) I cannot find what I'm looking for. It could take weeks to collect enough data to get the value I need and a long time sorting the data to find them.
Only idea I can think of is a little drastic if your not into soldering and that's to de-solder the temperature sensor so the temperature will never change and only humidity values will alter.
As to the battery indicator bit, yes this probably could be wrong. Does the base station have several degrees of battery power indication (like bars on a mobile phone battery indicator) or is it a simple good/bad indication? Powering the sensor from a bench PSU would allow accurate voltage adjustments and the battery indicator on the base station could be noted as the power is slowly decreased and the data captured. This would help narrow down the battery bit(s).


I might try desoldering as I don't have problems with understanding it and there are no SMD elements. I just wonder how will sensor act without the temperature. :-)

How much data do you guess you need of the humidity only?

I might also look for some old AA batteries to test the indicator. I don't have laboratory PSU, only one running 3.3V but might to try get voltage down with resistor or sth.
Weather station only shows 'low' battery (if its good, nothing shows up).


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