Frequency hopping experiments on the NRF24

Any old or new electronic projects on the go
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tiptipflyer
Posts: 393
Joined: 16 Feb 2018, 22:49
Location: Germany

Re: Frequency hopping experiments on the NRF24

Post by tiptipflyer »

Since my back is hurting very much that I cannot leave the house, I made a special boat radio using the NRF24 unit and an old robbe Starion transmitter.
The radio is intended for multi engined boats.
The right stick controls the rudder and the starboard motor (forward and reverse)
The left stick controlls the port motor (forward and reverse)
With this setup you can manoeuver the boat very realisticaly by controlling the port and starboard motors independantly.
For cruising you flip the v-mix switch on and all motors are controlled by the left stick only (again forward and reverse). In cruise mode the third (center) motor (if available) is also controlled with the left stick, so "all ahead full" gives you full power with all motors on one stick.

The receiver setup is as follows:
channel 1 rudder
channel 2 port motor ESC
channel 3 starboard motor ESC
channel 4 center motor ESC
channel 5 aux prop channel
channel 6 aux two position switch

The left stick right and left movement is disabeled by setting it to zero, so the center motor is only working when all motors are coupled on the left stick by the v-mix switch.
I call it the v-mix switch because it is labeled that way on the Tx, there is no mixing actually involved.

For other functions I added two more channels to the project, one proportional controlled by the knob on the right hand side of the Tx, and one switch channel controlled by the switch on the right side, making it a six channel radio now.

It is working great on the workbench, so I will test it in the near future on my three motor Graupner Dachs Torpedo boat.
BoatStarion1.JPG
BoatStarion3.JPG
BoatStarion4.JPG
Cheers
Frank
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tiptipflyer
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Joined: 16 Feb 2018, 22:49
Location: Germany

Re: Frequency hopping experiments on the NRF24

Post by tiptipflyer »

Phil_G wrote: 07 Aug 2020, 16:37 When you're feeling better Frank I would love to see the boat maneouvering... the special radio sounds great :D
I'm presently in a similar situation - I couldnt get up this morning, my back was so bad, I had to roll out and crawl to the bathroom :)
Spent most of today laying flat on the floor :D
Hi Phil,
I hope you get well soon.

Frank
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Wayne_H
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Location: Temora, NSW. Australia
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Re: Frequency hopping experiments on the NRF24

Post by Wayne_H »

I don't know what you two have been up to :o :oops: but I hope you recover asap.

My back issues are a direct result of lifting, moving & installing building materials every day - with basically no income due covid (until trans tasman travel is reopened) all I have is time & heaps of stock-piled materials, so lil 'ol me is da builder, fabricator, labourer, designer, etc, etc ;) :P :o Age has naff all to do with it :roll:

Perhaps another forum is needed..... ModeLayFlat???🤔
Cheers,

Wayne
Once a Retrobate, always a Retrobate............ ;)
RichardT
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Joined: 03 Mar 2019, 17:15
Location: Surrey

Re: Frequency hopping experiments on the NRF24

Post by RichardT »

Here's my attempt at Phil's excellent NRF project adapted for sailing boats and in particular winch operation. The RCS Guidance Sytem was originally modified 50 years ago with a tone mark/space controlled by the pot and simple multi-vibrator circuit for propo rudder. Full on/off tone triggered winch in/out with the uncontrolled rudder returning to neutral. Plenty of space in the tx where the 6v PP1s were for red board arduino and a couple of ex-laptop 18650s scavenged from the local recycling centre. The Futaba Challenger was an irresistible eBay find, many switches and pots. The reversing switches exposed when the battery cover is removed are great for all the options. It is rather large though! I did two versions of the receiver, one normal for standard servos and winches and a second version for a custom winch with its motor controlled by an arduino communicating over I2C with the receiver. All reasonably trouble-free apart from a duff set of rf-nanos which have the old nrf24l01 rather than the plus version despite the chip markings saying otherwise. Hopefully to be resolved by Keywish.
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Last edited by RichardT on 18 Aug 2020, 16:04, edited 1 time in total.
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Phil_G
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Re: Frequency hopping experiments on the NRF24

Post by Phil_G »

All good stuff Richard, nice to see that you've kept to the spirit of the pulse conversion.
It would be great to see a video of the boat and the set in action ;)
Luckily all my Keywish Nanos have been spot on so far, although I haven't tested the last batch... maybe I should ;)

I recovered the Vic Smeed 'Wing Ray' from my mums loft but the mast is missing, I might have some carbon tube here somewhere. Its not that well built - could do with some TLC :lol:

Cheers
Phil
IMG_20200817_214500_292.JPG
RichardT
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Location: Surrey

Re: Frequency hopping experiments on the NRF24

Post by RichardT »

The 'Wing Ray' looks interesting, perfect for a model where the practicalities of full-size sail handling don't apply. Wings should be at least as efficient as the normal bermuda style jib and mainsail, though I wonder what arrangement is made for sailing downwind. Does the wing move around to act as an aerofoil and sail a zig-zag course? Or, 90 degs to wind and act as drag? Would be great to see a video too. ;)

For anyone interested and unaware of how to easily check an rf-nano, here's a link, the CheckConnection.ino sketch is what you need at the very end of the forum post, swap the CE CSN pin definitions to match the rf-nano - https://forum.arduino.cc/index.php?topic=421081.15 - new Keywish rf-nanos are on their way to me, hopefully an isolated issue.

Also, note the 'art deco' style rudder knob on the RCS, must have come from the old radios I used to play around with, kept on the RCS for nostalgia reasons. The rusty bit just above the two buttons is also kept, I think I originally tried to cover it with Savlon, goodness knows why, to prevent infection?

Video challenge accepted, it has to be Eastbourne with its walk-around lake, I'm not quite confident enough to launch off into the unknown. :)
RichardT
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Location: Surrey

Re: Frequency hopping experiments on the NRF24

Post by RichardT »

New Keywish rf-nanos arrived this morning but have the same problem as the last lot. Can't set them to 250kbps. Tried setting via the rf24 library and directly via SPI but no luck. Anyone else had this problem? Waiting for Keywish to test my returned ones :(
bluejets
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Re: Frequency hopping experiments on the NRF24

Post by bluejets »

Isn't it done in the sketch...??

Code: Select all

radio.setDataRate(RF24_250KBPS); delayMicroseconds(500);
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Mike_K
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Re: Frequency hopping experiments on the NRF24

Post by Mike_K »

Is Keywish using the older NRF chipset that only did the faster speeds, but not the 250kbps. Look on the rf chip with a magnifying glass and check it's a NRF24L01+ and not the older NRF24L01. If it's the later it will never work at 250k.

Mike
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Phil_G
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Re: Frequency hopping experiments on the NRF24

Post by Phil_G »

This concerned me a bit as I've bought a stash of RF-Nanos, of which eight were as yet unopened.
Out of these eight, fresh out of the packet, seven apparently have the problem described by Richard and only one is fully working. One of the 'problem' chips has PTH holes which are too small for standard headers. This has teed me off as they recently doubled the price to over £5 each. All are marked as 'plus' variants.

The bad ones have the date marking "1913CL" and the good ones "1937BU"


badchip.jpg

goodchip.jpg


How did you get Keywish involved Richard?



Image


I did a simple test-script:

Code: Select all

// Simple test for plus/nonplus NRF24L01 on the Keywish RF-Nano, Phil_G 27/08/2020
// Load the sketch into your RF-Nano via the USB & bootloader, when its finished loading 
// open the IDE serial monitor which will need setting to 115200 baud. 
// Opening the serial monitor will cause a reset and after a second or so the result 
// should pop up. During this second its important that you cross your fingers :D

#include <SPI.h>
#include "RF24.h"
RF24 radio(10, 9);  // CE & CSN pins on the Keywish RF-Nano. Use (7, 8) for the Tstar Tech red
/********************************************************************************************/

void setup() {
  Serial.begin(115200);
  radio.begin();
  bool isplus = radio.isPVariant();
  Serial.print("Version test result =  ");
  Serial.print(isplus);
  if(isplus) Serial.println(", this is a PLUS");
  else Serial.println(", this is NOT a plus");
}

void loop() {
} 
I've done a 'contact seller' but I've little confidence that will achieve anything!
Phil to Keywish wrote:I have previously bought several of these items from Keywish and they have been perfect, however the most recent ones do not identify as "NRF24L01+" but "NRF24L01" and do not support 250k bitrate. This makes them unsuitable for my application as I need the 'PLUS' version. These are advertised as PLUS versions and are marked as such, but physically this appears not to be the case. At over £5 each these are expensive chips. Please advise.
I've confirmed that all the bad ones do work at 1MBPS, and surprisingly, I'm getting 25+ metres of range between two RF-Nanos.

This is disappointing but not the end of the world, I prefer the made-up 'promini & NRF' receivers to the RF-Nanos anyway. Not seen this on any standalone NRF24L01+ or +PA+LNA boards as yet.
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