Frequency Hopping experiments on the NRF24 & full tx/rx

[Phil_G]

Not sure if there is still interest in this project, I hope so coz it continues to give a lot of very rewarding fun at little expense.

The most recent change (actually a couple of years ago) was that mixer and reversing functions happen within each individual receiver rather than in the transmitter.
Posh transmitters hold lots of configuration, trim & mixer settings in model memories, but in the context of this simple project, moving these functions into the receiver makes transmitter model memories redundant. If a model needs a surface reversing, the reversal in stored and performed in that models individual receiver, which to me is far more logical than selecting a model memory in the transmitter. This means I can fly a variety of model types, full-house, RET or an elevon flying wing, regardless of servo directions - with any of my transmitters, propo, reed or s/c - without any binding, changing or selecting anything on the transmitter, just pick it up & go.

To reverse a surface, with the transmitter powered on and operating normally, hold the appropriate transmitter stick hard over whilst powering on the receiver. The setting is retained in that one particular receiver's flash, and of course only affects that receiver. Nothing changes in the transmitter. The elevon mixer is also in the receiver. This concept has actually been in use for about 2 years but I've only just got around to posting it

Also theres a #define for Tobes reversed traffic LED which makes it simple to correct, saves all the messing about swapping A0 & A1.
This is the original 5volt LED polarity which uses:
#define LEDBIT 1 // Tobes early PCB has reversed LED, set to 1 or 2

led.jpg (1.88 KiB) Viewed 7852 times

On the early Tobe PCBs this LED was reversed, in which case use:
#define LEDBIT 2 // Tobes early PCB has reversed LED, set to 1 or 2

Because of the huge combination of mixing functions, ratios & reversing, the optional mixer is best set at compile time, all the mixes are there, just set
#define mix_option 'V'
or
#define mix_option 6040
...as required, and uncomment any necessary reversing lines.
5050, 7525 & 6040 mix aileron & elevator for flying wings; 'V' mixes rudder & elevator for aileron Vtail models.
Or #define mix_option 0 if the mixer is not required in that particular receiver.

This recent update is only to the receiver code, and since changing the master zip file loses the download count, I've attached the 'new' receiver code separately. There are no changes to the transmitter, I havent even taken out the (now obsolete) transmitter reversing or mixers.

l've updated the concise 'how to' document at the top of the first post, also freshened other files, all up to date as of the last release.
Of course I'm continually developing it but I dont generally post anything until its well proven on the bench and in the air (me, Shaun, Rob, & Ron)

Cheers
Phil

[previous download count lost, was 78]

[Phil_G]

I've never done a 'family photo' as my sets are all different with no common 'theme', but this is my NRF line-up, all of these are in regular use apart from the Cannon which hasnt flown yet - hopefully soon - all converted to 2.4g at minimal cost based on this project
Any of these can be used with any of my models without any binding, changing or selecting anything on the transmitter, all the configuration differences being stored in the individual receivers. There are a few bench-test sets too but I dont count them as 'flyers'

Left to right:

Micro 2ch propo, OS Pixie S/C, RS Navigator S/C, Car tx behind, homebrew pocket 2ch, Digimac 1+1, 2ch Tobestick, Cannon, Flight-link Duette, and the World-Engines Talisman:

[Shaun]

You need more pal.

[Rene]

Not sure if there is still interest in this project, I hope so cos its been a lot of very rewarding fun

Definately so, thanks Phil, please keep up the good work.

Regards,
René

[Wayne_H]

Not sure if there is still interest in this project, I hope so cos its been a lot of very rewarding fun

Absolutely Phil, please keep going.

Before my transplant I enjoyed immensly making & using lots of nrf based sets/components. Now that my recovery is well underway, I'm looking forward to many more such projects

Thanks mate!

[Phil_G]

Thanks lads

FHSS version of the Reeduino

[jmp_blackfoot]

My just finished first NRF tx and rx are working fine and I am very happy, however I have a couple of questions:

First, the NRF24L01 chip allows for chosing frequencies between 2.400 and 2.525 GHz (channels 0 to 125) while countries have various frequency allocations for model control.
Just checking the FAI site (*) reveals that most European countries limit the band as 2.400 to 2.4835 GHz while checking the AMA site (**) indicates that in the US limits are 2.400 to 2.485 GHz. Even the Large Model Association (***) quotes 2.400 to 2.48355 GHz as legal in the UK.
Seems to me it would be prudent to limit one's version of the NRF to 16 hopping channels numbered 0 to 83, i.e. frequencies between 2.400 and 2.483 Ghz to be sure to comply with regulations and not use channel numbers 84 to 125.

Second, the LED between A0 and A1 blinks on my receiver at a pretty steady 8 Hz. Does this mean is checks every 25 packets?

A very happy Christmas to all.

(*) https://www.fai.org/page/frequencies
(**) https://www.modelaircraft.org/sites/def ... es/928.pdf
(***) https://www.largemodelassociation.com/i ... ies-in-uk/

[Phil_G]

Hi Jean-Marie and a belated Merry Christmas to you & yours!
First of all thank you for giving the project a try Which did you go for, the S/C, 1+1, Reed or propo?

Regarding channel allocation within the band, theres a note (actually a note in red!) to that very effect in the first post of the thread, added after Pete made the same observation: viewtopic.php?p=13598#p13598. I thought it was mentioned in the docs too but I'm not sure, I'll check - I may have missed it.

The rx LED simply counts received packets and flips the led state every 10 packets, ie a complete flash every 20 packets so with 100% reception it should flash at 10hz (20packets x 5ms = 100ms) so at a steady 8hz its indicating that some packets arent getting through for some reason.

Assuming your tx & rx channel lists match, the packet rate suggests that one or more of your chosen channels may be occupied, possibly a router, doorbell, local video link or whatever - but thats ok, no problem. You could try either a different location or a different choice of channels. John saw the very same here, if you read this and the following few posts (over the page): viewtopic.php?p=13600#p13600

Although its not a 'problem' as its the very thing that gives the set its resilience, its nice to get a good 100% rate on the bench if you can

Cheers & thanks again!
Phil

[jmp_blackfoot]

Phil,
Thank you for your explanation of the missed packets being due to the strong wifi channels in my neighbourhood. That has to be it.
As for the advice to limit to channels under 83, I had not seen it in the first post I happen to be colour blind to red in particular...
I always have to actually measure resistors to distinguish between the 15k and the 51k for example.
To answer your question, I did the propo version to start with and should fly it at the "Freeze Fly" our club traditionally organizes every January 1st at 9:00 am.

[Phil_G]

... with and should fly it at the "Freeze Fly" our club traditionally organizes every January 1st at 9:00 am.

Brrrrr !

Last Birthday my kids bought me a pair of lithium handwarmers, they really are amazing, 3 heat settings, easily last all day, and so much more reliable and less faff than the petrol or charcoal ones I'd used previously. Highly recommended! At a recent Nont Sarahs slope session they were being passed around maybe 8 flyers all day!

Mike has a 'heated Skyleader' which is brilliant, separate lipo and a heat element (plenty of room in there), the idea would suit any metal-cased tx
This kind of thing mounted on the case inside back: https://www.ebay.co.uk/itm/226467820991
Cheers
Phil