Arduino 433 modules for Picaxe

friis

Senior Member
#1
Hi,
Can I use Arduino 433 MHz modules with rfout/rfin (manchester coding)? How?
Are Dorji 433 Mhz ASK modules still readily available? They appear not to be.
best regards
torben
 

oracacle

Senior Member
#2
try and find out, never used any RF modules myself but do know that often plastering Arduino on things help them sell. the chances are they will be fine.
 

AllyCat

Senior Member
#3
Hi,

Yes, in general a simple radio module sold to be used with an Arduino can also be used with a PICaxe, but it depends exactly what you want to do. It might still be worthwhile to use a NKM 2401 with the receiver (rather than RFIN) to prevent "blocking" of the main program.

Dorji do still appear to have a presence on ebay, for example here. But with radio, rather like brain surgery, if you need to ask how, perhaps you shouldn't be doing it. ;)

Cheers, Alan.
 
#4
I don't know what you mean by "Arduino 433 MHz modules", but I've been meaning to ask the following question....

Is it okay to post information about what I call an Arduino-RFM69 "communications module"? I view it the same as the Sure Electronics 2.4GHZ communications modules, and their weather-sensor modules, which use a PIC chip as a serial interface on the boards. I have had great luck using the cheap Arduino clones with RFM69 radios (433Mhz & 915Mhz: RFM69CW, RFMHW, RFMHCW, etc), and have come up with a TTL serial protocol that is "very easy" to implement and use with Picaxe. My protocol is a tweak of the LowPowerLab "node" and "gateway" code, which reads and sends Picaxe readable bytes. The LPL code has many powerful features for reliability and power conservation.

That said, I am an old Ham Radio guy and my MCU of choice is Picaxe. Nevertheless, when I could not get reliable communications from my remote weather station (100m with two barns in the path), even implementing a mid-point repeater, I started to look around. I do not have the coding skills to implement the wonderful work done on this forum by the user 'srnet', and I eventually stumbled onto the LPL resource.

I'll wait for authorization from hippy or the like before mentioning the "A-word" again ;-)
Greg
 

friis

Senior Member
#5
Hi,
I had a feeling that Dorji was'nt around any more - the latest NEWS on their home page were from 2014 when I started my project. So I started to look around for some replacement modules.
The Arduino modules did'nt work "out of the box". On the oscilloscope the shape of the curve from the sent/rfout looked alright, but the received curve looked strange.
I have decided to by the Dorji from ebay - the safe bet. But I have to look into the use of rfout and rfin.
Thanks
torben
 

lbenson

Senior Member
#6
Is it okay to post information about what I call an Arduino-RFM69 "communications module"?
I'm in no position to say authoritatively, but I would hate to think that because some seller on ebay uses the word, "arduino" as a modifier for a sensor or communication module (not an actual arduino MCU), it could not be mentioned on this site. For instance, the "37 In 1 Sensor Modules Kit Set For Arduino" includes nothing which is either restricted to arduino or in an arduino shield configuration. When I search on ebay or amazon for a module, I usually include "arduino" in the search term because it likely results in more items being returned, and often better prices.
 
#7
My hesitation to mentioning the A-word comes from the recently revived topic about “sorry picaxe but I leaving you for something new”. I am a Picaxe man and check this forum every day. I see the A-thing as an easy to use serial interface to a very robust radio module, and I have a feeling that others might be interested....
 
#9
There is plenty of feedback on ebay that's recent, so I think they may have decided against trying to build their own web store, and just gone with the ebay storefront. Which also might account for the lack of updates on their web page.
 

hippy

Technical Support
Staff member
#10
Is it okay to post information about what I call an Arduino-RFM69 "communications module"?
I think the best way to step round the 'is it PICAXE or is it promoting something else?' issue would be to post a link to an external web page which describes the thing rather than do that in detail here.
 
#11
@doppler - I wonder if you find it hard to interface the PICAXEs to RF modules? if so what is different... thanks..
I am very comfortable using the little 433Mhz (and 315Mhz) RF modules, using both straight serial and NKM2401 chips. This is also true for Sure Electronics 2.4Ghz modules, and Xbee modules. Those are simple serin/serout (or rfin/rfout) protocols. What would be hard for me is to come up with the SPI code for something as robust and feature rich as the RFM69 radios. I needed my data to travel 100m, with two barns (one metal, one concrete) in the line of sight, and then through the wall of my house. Even with a repeater on the corner of one barn, the 433Mhz modules just weren't powerful, or reliable enough. The 2.4Ghz radios have very limited penetration power.

Using the LPL code with RFM69 radios gives effortless access to features such as Automatic Transmission Control (ATC), which dials down the transmit power to a minimum level for reliable communications, and very robust error correction (i.e., request for re-transmit on bad CRC) handling. The high-power RM69 radios have a range of a few miles in open air, and penetrate my obstacles with 100% reliability. You can set them to unique network and node ID's for isolated network communications on the same frequency.

In short, it is a very easy to use, high power, reliable RF solution. To me it is the same as using a Xbee, but for cases where more power is needed. Just like I wouldn't want to try and develop an Xbee from scratch, I just want to plug-n-play an appropriate RF resource and move on.....
 
#12
I think the best way to step round the 'is it PICAXE or is it promoting something else?' issue would be to post a link to an external web page which describes the thing rather than do that in detail here.
Hippy, I thought I would post it under "User Projects - Communication", but I understand your concern. Thank you....., Greg

ALSO: My apologies to 'friis' and all for hijacking this thread
 

manuka

Senior Member
#14
Friis: It depends on what you intend! Aside from technical specs. (frequency, data rate, power, current drain, RSSI access,sensitivity, modulation schemes & error handling etc ) even "boring" aspects like module size, pin out spacing, budget, delivery time & supply voltage may influence choice. "Horses for courses " !!

I've had a good deal to do with Dorji over the years, much of it PICAXE related. Most of my orders (as recently as March 2018) have been directly from their Shenzhen (China) base via their ever helpful Mark Yao. Mark then indicated that new LoRa modules, presumably using Semtech's SX126x new RF engine, were due for release about now.

As far as I know, Dorji are still active retailers - a quick Google shows numerous products on their site. Here in NZ their "887" ASK receiver modules remain very popular educationally with diverse micros (RPi, PICAXE etc). Note - NZ & China have a free trade agreement which makes for extremely easy importing- we've no taxes levied on items valued under ~US$300 either.

For duplex (2 way) 433 MHz work the budget & versatile HC-12 (not a Dorji product of course) admirably tends first choice. Rev. Ed may well want to favour it...

Ruthless technical progress of course continues,with low supply (~3V) modules personally appealing. However the increasing abundance of small,smart & cheap rechargeable 3.6V-4.2V LiPo packs makes even that incidental!

HopeRF's CMOSTEK RFIC based 433 MHz ASK receivers (below) tend favour for both low supply needs & their outstanding performance in marginal links. They seem to work with any 433 MHz ASK TX and UART capable micro -refer the Forum discussion from Nov. 2017.

Stan.
 

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manuka

Senior Member
#16
Yes - they're interesting (& CHEAP !) 433.92MHz ASK receivers. Module data here,with a 5V RFM210LH (below) & a seemingly more sensitive (at lower data rates) SPI configured RFM210LW versions here.

With near throwaway prices and a mega competitive rapidly changing market,it's hard to credit that such hi-tech performance is worth bothering about for the makers !

Duplicated GND pins are for RF ground & supply ground -for simple links just one can usually be used. Many 433 MHz RX modules have such duplicated (or even NC ) pins, which can come in handy when hacking them for the likes of RSSI taps. Back in 2014 I isolated a "spare" pin for RSSI use on a Spirit-On module (below) Stan.
 

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#17
I'm a fan of the HC-12 transceivers: my preferred wireless module.

I have also used the cheap ASK modules for one-way wireless links. I have found that there are two 'levels' of ASK receiver - check for a crystal on the receiver board like on Stan's attachment (Jaycar ZW3102) above. I have had far too many problems with misaligned, cheap receiver boards with LC (or RC?) tuning. Save yourself some grief and leave the crystal-less modules in the shop! No problems with the transmitter modules - all seem to have on-board crystals.
 
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