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Topic: oregon scientific sensor simulation: don't work but is strange (Read 949 times) previous topic - next topic

giovannimarletta

Hi everybody, I've tryed to decode some oregons sensors with arduino and libraries like WlessOregonV2 and Oregon.

It work fine with a commercial rx board on 433,920 MHZ, is can decode every sensors from oregon, it decode as well another arduino board with a transmitter simulating arduino thgr228n sensor, till now no problem.

the issue is that no one oregon original base seems capable to decode the arduino trasmitter, what it can be ?

believe i've tested everything  ...
MAGIS UTILE HIS EST ARTIBUS HIS QUAE NIHL UTILITATIS HABENT

mauried

Its most likley because Oregon Consoles require all the data fields in the transmissions to be present and that includes the 2 CRCs at the end , which many non oregon decoders ignore, as they arnt needed to extract the actual temperature data.
Also real Oregon sensors use a modified form of Manchester coding which is slightly differant to normal symmetrical manchester coding, so unless the reconstructed transmission replicates the differances, the Oregon Console ignores it.
 

giovannimarletta

so, i believe understand that is definitively impossible emulate a "perfect" oregon sensor trasmission ?
it's true ?
MAGIS UTILE HIS EST ARTIBUS HIS QUAE NIHL UTILITATIS HABENT

mauried

Not impossible, but pretty hard.
Havnt seen anyone so far perfect it.
I tried some years ago with a PIC and a DHT22 sensor and got it to partially work, but wasnt reliable.

giovannimarletta

yes, I've verified with all methods avalilable, now it's easy decode the original oregon sensors, it will be real useful implement this data source by hardware/app hobbysts maded.

about precision, the differences between the oregon sensor and the commercial sensor is big, the oregons are pretty correct but cost a lot, so ? I can "steal" a lot of oregon transmission from my nice neighbours.
MAGIS UTILE HIS EST ARTIBUS HIS QUAE NIHL UTILITATIS HABENT

jremington

Quote
so, i believe understand that is definitively impossible emulate a "perfect" oregon sensor trasmission ?
Not true. There are several different Oregon Scientific RF protocols, and I believe all of them have been successfully emulated.

Exactly which protocol (or which module) do you want to emulate?

giovannimarletta

the oregon bases are various, neither are capable to decode on my arduino based trasmission, there are emr812hgn, mr238t and bar898hg, every of those bases receive data from the oregon sensor thgr228n, this one, transmit temperature and air pressure, the protocol are surely the v 2.1.
that's all that I know for now ...
MAGIS UTILE HIS EST ARTIBUS HIS QUAE NIHL UTILITATIS HABENT

mauried

Oregon Consoles have a gated 433 Mhz receiver in them to save battery power, as most consoles are designed to run off batteries.
The Oregon sensors all transmit at fixed precise times using an internal 32768 Khz watch crystal .
The sensors have to be synchronised initially with the console before they will be recognised and then the console knows when to expect incoming transmissions.
Usually, the synchronization is done by pressing a reset button on the console which turns the receiver on for around 5 minutes which is long enuf to pick up any nearby sensors.
If however, the console wont pick up your sensor in the 5 minutes, then something else is the problem.
Ive no experiance with V2.1 sensors.

giovannimarletta

which library you use ? OregonDecoderV2 or Oregon ?
or the Olivier Lebrun / Jonathan Martin code ?
it work with arduino based decoder but I've used every of these without success with oregon bases.
can you suggest me some skecth for testing ?
MAGIS UTILE HIS EST ARTIBUS HIS QUAE NIHL UTILITATIS HABENT

mauried

The only real way to figure out whats going on is to record on a cro or some kind of data analyser exactly what the Sensor is transmitting, and then compare it to what your library is sending.
If v2.1 sensors are like v3 sensors, the MSB of each data nibble has its timing altered slightly from the 3 other data bits in the nibble.
You have to reconstruct the data stream the sensor sends exactly or the console wont recognise it.
You also must have the correct CRCs at the end of the data stream.
Its not an easy task.

jremington

Here is a successful emulation of an Oregon Scientific V3 sensor. It is even easier to do V2.1

giovannimarletta

MAGIS UTILE HIS EST ARTIBUS HIS QUAE NIHL UTILITATIS HABENT

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