nRF 905 with picaxe?

Pauly1980

New Member
Hi all,

Just wondering if anyone has some sample code to get an nRF905 transciever running with any of the picaxe chips?
I have no real project need for it right now but it is just something I would like to have a play with. Might be useful when I get back home in 8 months for some simple data transfers around my property with data like tank levels, shed temps etc.


Cheers,
Pauly
 

manuka

Senior Member
Brrr ! Nordic's nRF905 was mentioned on the PICAXE Forum about 5 years ago - see here. Although superior to classic ASK modules the feeling was that it was no great performer for the effort involved.

These days Chinese HC-12 modules may be a better choicer for your needs. They've been extensively discussed on this Forum ! Stan.
 

Pauly1980

New Member
Thanks Stan,

Unfortunately for me these are what I have and at this time of year I have no hope of getting anything delivered down here for another 8 months. I might just have to get them running with the arduino's first and then try to port some code across.
Thanks,
Pauly
 

premelec

Senior Member
That's difficult situation! Let us know if you get 'em going - I have some of those I couldn't figure out... ;-0 Hope they are in heated environment.
 

Goeytex

Senior Member
Hi Pauly,

Seems the somewhat recent love affairs with cheap HC-12's and with LoRa devices has left you with no offers of assistance. Understanding you isolated situation and inability to order alternative RF devices, I will give it a stab. But first you need to tell me what resources you have available.

What specific Picaxe chips are available?. Breadboards?. Power supplies? Test Equipment?. What specific Nordic 905 device do you have?

The more detailed and specific your answers, the better the assistance will be.

Goey
 

Pauly1980

New Member
Hi Pauly,

Seems the somewhat recent love affairs with cheap HC-12's and with LoRa devices has left you with no offers of assistance. Understanding you isolated situation and inability to order alternative RF devices, I will give it a stab. But first you need to tell me what resources you have available.

What specific Picaxe chips are available?. Breadboards?. Power supplies? Test Equipment?. What specific Nordic 905 device do you have?



Goey


Thanks Goey,

I'm happy to bang away at it, the challenge can be half the fun but help is always nice.

Pretty sure I have 2 of 28x2's, 1 of 28x1, 4 of 18m2, 5 of 08m2, 1 of 40x1

I have access to CRO's, signal generators, got heaps of LM78xx chips for power supplies, ATX power supplies if I need more current, some lab power supplies.
The comms guys here have some network analysers as well which I haven't had a chance to play with but apparently they can do a lot of stuff like analyse antenna resonant frequencies etc.

As to the 905 device I have as far as I know its just a nordic nRF905 shield but I will take some photos after work and throw them up here

Thanks,
Pauly
 

Goeytex

Senior Member
@Pauly

There are some things you need to do first.

1. Determine the appropriate frequency band for your location.
A. This device can operates in three bands 400MHz,868MHz or 915MHz Bands.
You should know what is legal there and what will not intefere with
any devices currently being used.

2. Attach flying leads to the RF module since the dual row header is not
appropriate for use with a breadboard.

3. Set up a 3.3V Power source for the Breadboard. Both the Picaxe and NRF module
will be operating at 3.3V. If you plan on using a 5V LCD display then you will need
both 5V and 3.3V. (An ATX power supply brings out both 5V and 3.3V.) Some users here
will discourage the use of an ATX supply. However I like them because of the fast shutdown
on a short circuit situation. But since they can potentially supply a lot of current, I suggest
using a 500ma fuse on both 5V and 3.3V outputs. It is also a good idea to put a 1/2 watt 50 ohm
resistor across each output to Gnd as a minimum load. This may help regulation in a no load/ Low load
situation. Most modern ATX type suplies do not need the resistors but it does not hurt. Two 1/4 watt
100R resistors in parallel will also work if you do not have 1/2 watt.

4. Download the NRF905 Datasheet and have is ready for reference.

5. Set up a Picaxe 28X2 on the breadboard and make sure that you can program it using a simple
test program that blinks an LED.

Get all this done an I will first cobble together some picaxe basic code that verifies SPI communication
between the NRF 905 module and the Picaxe.

Oh, and clean up that breadboard ! . A toothbrush and some Iso Alcohol will work great. Let it air "dry" for at least an hour after cleaning. I sometimes scrub using hot water with dishwashing liquid, followed by a good rinse and shake dry. Then follow that with the alcohol scrub and a forced air dry or by placing in an oven set to warm for 15 min or so. Instead of the oven, you could use the plate warmer or Heated Dry function of an automatic dishwasher if one is available.

Let me know when you are ready.
 
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manuka

Senior Member
Pauly 1980: Google shows Davis is a "mere" 4.5 hours from Hobart (Tasmania). In spite of such isolation it seems you have decent internet links? Have you hence read thru' the nRF905 data sheets?

At least you've dry Antarctic air, & urban RF clutter & trees should be absent (!) but device limitations may arise. Although I've not used the nRF905 it's speculated that the 10mW max TX output power (25mW allowed Aus/NZ) & very modest RX sensitivity (just -100dBm) may well be limitating issues, even when driving software is tamed... Stan.
 

Pauly1980

New Member
Pauly 1980: Google shows Davis is a "mere" 4.5 hours from Hobart (Tasmania). In spite of such isolation it seems you have decent internet links? Have you hence read thru' the nRF905 data sheets?

At least you've dry Antarctic air, & urban RF clutter & trees should be absent (!) but device limitations may arise. Although I've not used the nRF905 it's speculated that the 10mW max TX output power (25mW allowed Aus/NZ) & very modest RX sensitivity (just -100dBm) may well be limitating issues, even when driving software is tamed... Stan.
4.5 hours would possibly be achievable if we could land a large jet here but unfortunately that is not the case. It took 14 days on an icebreaker to get here :(

Update: I teasingly speculate that astonishing Aurora displays -recently visible even here in subtropical NZ- may result from "our man on the ice" firing up his nRF905 ? You could almost see the effects of his software tweaks !
Hahaha... It's more likely the 70kW radar we have measuring the upper atmosphere than a 50mW module :)

I need to pull my finger out and get back onto this but it's amazing just how fast the days go by down here.
 
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