nrf24l01

Wireless & IoT
1

I have 2 nrf2401 modules that currently communicate with each other. The reliability

is not very good (80 % at 5 meters) and am considering switching to the 24L01 modules.

The effort required to get this far was non-trivial and I do not want to start over for

a small potential improvement. Any thoughts or statistics?

Regards,

George

2

link to seattlerobotics you might want to read in this thread:

http://www.sparkfun.com/cgi-bin/phpbb/v … php?t=2946

The links to the photos are broken. They were ok a couple days ago.

3

I found the article o seattlerobotics very informative. I had very similiar experience

in getting started. I would like to hear from nrf2401 (or other low cast radios) users

with regard to transmission schemes, effective data rate, error recover, etc. Working

sollo with unfamiliar technology can tax ones mental resources.

4

Did you see the article in CircuitCellar? Written by one of the forum members.

http://www.sparkfun.com/cgi-bin/phpbb/v … php?t=2774

5

I’m having similar problems w/ the TRW24G. Transmission is good as long as both TX and RX are on the same bread board, but I have problems as soon as I separate them. At about 5 meters i loose 50% of the transmitted packets!!! This is true even @250Kbps.

It seems like we just have to live w/ this and code an ACK loop to guarantee transmission. This takes your through put to a fraction of what the datasheet states… An also makes things much more complicated.

If you have any luck please let us know.

6

Are you guys using the MiRF-v2 (which uses nRF24L01 chip)? What kind of antenna?

I asked about MiRF-v2 on this board. Sparky says:

Testing outside on a clear day, the MiRF v2 with ceramic antenna was really pretty short range - like 10-15 feet.

Same day, same setup, two MiRF v2s with RPSMA antenna (small guy) was surprisingly far. How far? We should have taken pictures and a GPS unit. I’d say 140ish feet. Down the parking lot, aross the stree, and up a little hill. It was still low power signal though → the signal went away as soon as trees or our building got in the way.â€

7

Orod:
I’m having similar problems w/ the TRW24G. Transmission is good as long as both TX and RX are on the same bread board, but I have problems as soon as I separate them. At about 5 meters i loose 50% of the transmitted packets!!! This is true even @250Kbps.

It seems like we just have to live w/ this and code an ACK loop to guarantee transmission. This takes your through put to a fraction of what the datasheet states… An also makes things much more complicated.

If you have any luck please let us know.

Really? We were able to blast audio through walls with steel studs with some packet loss, but the music was still quite clear. Not to mention it was definitely very clear with line of sight. We were using the 1Mbps mode with 16crc and 32bit address. Transmitting across our lab we lost maybe 1 packet per every 50.

Keep in mind the datasheet NEVER mentions throughput. They talk about on-air data rate. This just tells you the modulation speed. To calculate throughput you have to add up the time-on-air, CE delay, and SPI delay. This will then give you an accurate measure for the throughput (~330kbps which was confirmed by Nordic)