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NRF24L01+ With PIC

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Suraj143

Active Member
Guys I made a wireless link using two NRF24L01+ & two MCU units.I want to toggle the reciever side LED bulb when the transmitter side switch presses.

*NRF24L01+ (Black colour Modules)
*SPI Data Rate 250Kbps
*NRF Air Data Rate 250Kbps
*Auto Ack OFF
*4 Bytes payload
*10uF cap on power rails

The problem is the reciever misses many packets even in 10 feet range.Even when I cross my hand it won't send data.

Will the auto acknowledge will improve my problem?
 

dougy83

Well-Known Member
You have to make sure that the receiver of one module is enabled when the transmitter of the other module is transmitting, otherwise you won't receive anything.

If the auto-ack is anything like that used by the ANT protocol transceivers (i.e. it retries up to x times if no ack is received), then yes, it will improve reliability.
 

spec

Well-Known Member
Most Helpful Member
It is not clear what you want.

To detect when the transmitter switch is pressed, you need an RF detector at the receiver.
If you really need reliable data exchange on a poor communications link you need to chose an appropriate link protocol.

By the way, it sounds like your fundamental Tx/Rx system need investigating and sorting.:)

spec
 
Last edited:

ericgibbs

Well-Known Member
Most Helpful Member
The problem is the receiver misses many packets even in 10 feet range.Even when I cross my hand it won't send data.
hi Suraj,
I had the same problems, the range of these NRF24 modules is very limited when using the onboard printed circuit aerial, even the slightest interference causes lost data.
Any object passing between the TX and RX 'line of sight' caused data loss.

I did have a master TX NRF24 talking to 4 remote NRF24 RX units over a distance of 4 to 5 metres, the results were unacceptable. I experimented with added home made dipole aerials with little success.

There are commercial dipole aerials available.

Finally abandoned the NRF modules and used HC12 TXR modules for the project, ranges up to 100 mtrs are not a problem.

E
 

Suraj143

Active Member
Thanks guys for the inputs.

hi Suraj,
I had the same problems, the range of these NRF24 modules is very limited when using the onboard printed circuit aerial, even the slightest interference causes lost data.
Any object passing between the TX and RX 'line of sight' caused data loss.

I did have a master TX NRF24 talking to 4 remote NRF24 RX units over a distance of 4 to 5 metres, the results were unacceptable. I experimented with added home made dipole aerials with little success.

There are commercial dipole aerials available.

Finally abandoned the NRF modules and used HC12 TXR modules for the project, ranges up to 100 mtrs are not a problem.

E
Hi Eric.In your project did you use Auto acknowledge feature?I have not set up auto ACK feature.I just checking the RX_DR flag bit when receive data.I think I have to use auto ACK feature & see.
 

ericgibbs

Well-Known Member
Most Helpful Member
hi S,
I did not use the ACK, only the Bit in the RX_DR, which was used to raise an Interrupt on PORTB.0
If you decide to try the ACK feature please let me know if it improves the performance, if so I will try it.
E

BTW: are your NRF PCB,s vertical on TX and RX...?
 

Suraj143

Active Member
hi S,
I did not use the ACK, only the Bit in the RX_DR, which was used to raise an Interrupt on PORTB.0
If you decide to try the ACK feature please let me know if it improves the performance, if so I will try it.
E

BTW: are your NRF PCB,s vertical on TX and RX...?
Hi eric.

My nRF's are laid on vero board.Not vertically.My target is to make a very compact transmitter with very limited space.I'll definitely let you know after the auto ACK is made up.
 

DirtyLude

Well-Known Member
A lot of people have spotty reliability with these modules. I would try to make up a program for transmitter and receiver that cycles through channels and different packet size and logs results. I saw an Arduino sketch like that around a while ago. Changing packet size for some reason can effect the reliability. I'll be doing this sometime myself, though I'm not using a PIC.

Which module are you using? There's the standard module you get with 8 pins and a more compact one that you can mount flush with a smaller inline connector. The smaller one is apparently very bad. I have a couple of these and haven't tried them out, yet.

I have a remote using an nrf24l01+ and it was working pretty well for a while with decent range. About 7 meters indoors at least. I played around with the receiver and it's not working at all now and I haven't gotten off my butt to figure out the problem. Oddly when I first got it working I found it seemed sensitive to voltage. Voltage it was getting was 3.5V, when I lowered the voltage to 2.8V it suddenly started to work.
 

Suraj143

Active Member
Hi I used the attached modules on both ends.

An RF expert told me that those are directional with onboard antenna stuff.Also it will not perform well within walls.

Even the nrf24L01 datasheet shows it perform well on very close applications like wireless keyboards,mouse etc....

Anyway my target is to build a 30m wireless node which can work inside buildings which contains several walls & It should be powered from a 3V battery.

I just start reading on NRF905 which can work on 433Mhz range.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Hi I used the attached modules on both ends.

An RF expert told me that those are directional with onboard antenna stuff.Also it will not perform well within walls.

Even the nrf24L01 datasheet shows it perform well on very close applications like wireless keyboards,mouse etc....

Anyway my target is to build a 30m wireless node which can work inside buildings which contains several walls & It should be powered from a 3V battery.

I just start reading on NRF905 which can work on 433Mhz range.
Look at the HC-12 modules, lot's of range, and dead simple to use.
 
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