Sensor radio vs Bluetooth ?
-
Hey;
I have reason to believe my laptop's bluetooth to be interferring with gateway/sensor communication. Is this possible? At least technically, as the nrf24 relies on 2.4Ghz (same as Bluetooth), this sounds plausible. Has anyone experinced this? -
Bluetooth uses frequency hopping, so it never stays at the same frequency for that long,
That being said, it could interfere slightly.. could jam the input in the nrf, if they are very close to each other, not because it transmits on the same frequency, but in the same band. If a high signal is received on adjacent channels, the radio might loose some sensitivity.
You could try to use one of the higher frequencies that the NRF supports (I think it can go above 2.5Ghz, which is outside the bluetooth spectrum). Also you could try to turn off the bluetooth first, and see if that helps on radio sensitivity
-
Bluetooth uses frequency hopping, so it never stays at the same frequency for that long,
That being said, it could interfere slightly.. could jam the input in the nrf, if they are very close to each other, not because it transmits on the same frequency, but in the same band. If a high signal is received on adjacent channels, the radio might loose some sensitivity.
You could try to use one of the higher frequencies that the NRF supports (I think it can go above 2.5Ghz, which is outside the bluetooth spectrum). Also you could try to turn off the bluetooth first, and see if that helps on radio sensitivity
@tbowmo said:
Bluetooth uses frequency hopping, so it never stays at the same frequency for that long,
That being said, it could interfere slightly.. could jam the input in the nrf, if they are very close to each other, not because it transmits on the same frequency, but in the same band. If a high signal is received on adjacent channels, the radio might loose some sensitivity.
You could try to use one of the higher frequencies that the NRF supports (I think it can go above 2.5Ghz, which is outside the bluetooth spectrum). Also you could try to turn off the bluetooth first, and see if that helps on radio sensitivity
Thanks for your answer
I will try with the bluetooth off.Any other suggestion on how to debug communication between gateway & Sensors?
Thanks! -
Have you tried decoupling the radio in both ends with something like 4.7uF low ESR capacitor?
Search the forum, there's lot's of advices.
@tbowmo said:
Have you tried decoupling the radio in both ends with something like 4.7uF low ESR capacitor?
Search the forum, there's lot's of advices.
In my particular case sending by the gw seems to be the problem.
I will try this trick with the capacitor as well, thanks! -
Bluetooth indeed hops around in the 2.4 GHz band split in 100 kHz bands but Bluetooth has an algorithm to stay out channel that are occupied. For that to work, Bluetooth has off coarse to see the other "user" and if the channel is not used that often that can take time or will not work.
But .. provided that Bluetooth stays out the band you are using for MySensors there is still a possible problem in that the nRF24L01+ (like almost all 2.4 receiving IC's) has a wide-band LNA followed by a mixer followed by filtering and more gain. The wide-band will see both the Bluetooth and the Signal Of Interest (SOI) and if the level of Bluetooth if much larger than the SOI things will also go wrong.
So if you have Bluetooth at 50 cm, it will probably come in around -30 dBm, the nRF24L01+ can receive signals up to -85/-94 dBm and this kind of level differences can give problems, see also Table 7 of the nRF24L01+ datasheet.
