Dorji TX/RX Modules ?

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Brian M

Member
I would like to try the Dorji 886 TX/RX modules on a remote monitoring project I have in mind, but trying to find a supplier in or close to the UK is proving to be a bit of a problem. I don't know if I am missing something, but just can't seem to find anything using the usual search engines, forum search or even manufacturers web site.

Manuka really seems to think they do the job well and the cost is good.

Anyone help with some info on suppliers please?
 
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manuka

Senior Member
??? 886 -is that MHz ???? What's your application? What range ? What data rate ? What power supply?

I've NOT recommended any Dorji offerings for that frequency, but have often stressed that their cheapie 433 MHz ASK modules (with a trifling 10 or 25 mW) are near bullet proof for wireless data newbies.

Dorji do also make diverse GFSK transceiver modules,some of which are sub 1GHz, so check the likes of this or even my humble DRF7020D13 review. Dorji's ADF engined modules however are now considered small beer to their more recent Silab offerings.

In terms of a supplier, I sadly relate that modern day Asia (of which Australia/NZ are a part) now neglects Europe at the expense of such "minnows" as billion strong India, so perhaps contact Dorji directly,or use Australian outlet Wiltronics - it's the global village after all! Stan.
 
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SAborn

Senior Member
Personally i think the DRF4432D201-L1 is the best dorji module to suit the picaxe, its 100% straight serial connection using the programming port and Sertxd command, good range and the power can be reduced so not to offend anyone in the area, simple setup tool downloaded from Dorji.

If you want to send data direct to a PC then the DRF4432D201-M1 coupled to the USB adapter make a small USB dongle that plugs direct into a PC usb port as a serial port.

Both wireless modules listed above are 100% compatable with each other and can be mixed and matched, as they have selectable addresses it eliminates much of the airway pollution on the 443mhz band, IMO they are the best suited picaxe wireless modules i have ever used out of a long list of tested modules.

http://dorji.com/docs/data/DRF4432D20I.pdf
 
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Dippy

Moderator
In addition to Rev-Ed's fine offerings there are more RF module makers than you can shake a stick at.


I'd be surprised if Dorji is avoiding the Euro market in favour of others - anyone sells to anyone, especially via Ebay and Alibaba..
After all, it's not like RF modules take much space or much financial risk .
May be they can't get a foot in the crowded Euro door? Or maybe non-compliant? Maybe others are simply 'better'? Margins? Who knows?


I don't know your budget Brian, though most PICAXErs are 'careful', so look around.
Get Data Sheets from places like Farnell and then shop around.
Check out, for example, the module made by AMBER (AMB8420 / AMB8425-M).or ANAREN - (A1101R04C00GM or A110LR09A00GM).


If you can work at a more nitty-gritty level then check the MRF89 module:
http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=1823144&MER=baynote-1823144-pr

If you want a cheapo compliant 430-439MHz SPI module then check RF SOLUTIONS - ALPHA-TRX433S

So much choice... and confusion :)
 
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manuka

Senior Member
Dippy: Indeed - which is why I endlessly stress that folks should S T A R T .... S I M P L Y !

As an aside to SAborn's post, that fine module's channel nature means it's -argh!-restricted to only a few legal settings. At 433 MHz (where a generously wide ~1,6MHz band slot is available) only it's Ch. 19 setting of 433.920 MHz can be used! That "4432" refers to SiLab's RF engine by the way, & not the 433 (MHz) frequency.
 

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Dippy

Moderator
That's a bummer re: 433 band. Can it be set by host micro or is it locked in formware?
If the latter then they really haven't thought that one through.
433.92MHz is very common amongst single-chan manufs, so that's just asking for interference.
I think I'd stick to the Alpha for 433/434 work.


What RF chip do they use for the nitty-gritty?
When I looked at the command structure a couple of years back it looked very MRF - whether it was MRF or clone I don't know.


Just out of interest, have Dorji got certification to show compliance in Europe?
 
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Goeytex

Senior Member
I can vouch for the quality and functionality of the Dorji DRF4432D20I modules. And as far as keeping it simple, these are just as easy if not easier to use and set up as the cheapie ASK modules. Not only do you get great range, but the data is packetized with error correction, and the frequency is adjustable by channels spaced 1 MHz apart. These modules integrate nicely with any Picaxe.

The problem with the Dorji modules is the supply chain. They have no presence on Ebay, but might be on Alibaba or that other Asian site. You can order directly from Dorji by sending them an email. Mark Yao is the contact and is great to work with.
 
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manuka

Senior Member
Agreed on Dorji's Mark - he's real gentleman,with warm & rapid email responses of "Oxbridge English" calibre!

By chance Mark has just informed me of a sleek new SPI linked SI4463 based 433 MHz DRF4463F modem module that has amazing RX sensitivity & data speed. Yikes - it's only US$6 too ! Their more traditional ~US$20 DRF4463D20, which is itself very new,is reviewed at a recent DesignSpark posting. Mmm-the poster should be alerted to 433 MHz power levels however, as the normal UK limit is 10mW- he seems to be using 100mW!

Dorji products can be purchased directly from Tindiehttps://www.tindie.com/ , with the DRF4463D20 here. If you've not heard of this crowd then perhaps read this. For those with innovative e-projects Tindie may be just the outlet in fact.

My "copyleft" review of Dorji's plain ASK modules, is also mentioned (scroll down). These modules apparently sell at just US$8 for 2 x TX and 2 x RX. Even with (modest) p&p this is under half their Wiltronics/Surplustronics prices in Aust/NZ!

Dorji are not perfect however, as their much published 433 (315?)MHz transmitter view is still -sigh- mirror imaged ! At one stage their RX module was too -which must have caused no end of head scratching! I let them know this well over a year back in fact...
Stan.
 

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srnet

Senior Member
The Si4463 could turn out to be a very useful chip indeed.

It will operate in the 2M amateur band, so for 'PICAXE In Space' use (launch date November 21st) we would have had an extra 10dB of receive margin due to reduced path loss.

As yet however (I asked SI) no-one makes a module in the style of the RFM22 and similar Dorji offerings, using the Si4463, that allows direct access to the frequency settings registers etc.

One big plus, the Si4463 does not have the so called 'smart reset' of the Si4432, so should be far more suited to high reliability uses.
 
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Goeytex

Senior Member
As yet however (I asked SI) no-one makes a module in the style of the RFM22 and similar Dorji offerings, using the Si4463, that allows direct access to the frequency settings registers etc.
Click to expand...
What about this one ? ======> DRF4463F
 
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srnet

Senior Member
I misread the data sheet for that one, thought it was 433Mhz only, although at the time I spoke to Si (a couple of months ago) it did not exist.

I had read the data sheet for the Si4463 some time ago, the set up and control is completely different to the Si4432, not sure why they changed it so much. Its going to take a while to work through the API information to work out how to set it up.
 
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srnet

Senior Member
By chance Mark has just informed me of a sleek new SPI linked SI4463 based 433 MHz DRF4463F modem module that has amazing RX sensitivity & data speed.
Click to expand...
Now the Si4463 uses a complete different software interface to the Si4432, and its a bit late for 'PICAXE in space' but if it can be made to receive the Si4432 packets and that extra 5dB of receive sensitivity is real, that could make a significant difference to receiving packets from 1000km away.
 
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manuka

Senior Member
Brian M: OK - it's assumed hence that you'd meant 433 MHz all along? Best to order Dorji modules from that Tindie site I'd say, as Dorji themselves are the producers & less organised for small orders.

srnet: I'd not realised myself that Dorji's DRF4463F (which of course uses SiLab's new Si4463) covers (according to their Aug. 2013 data sheets) 403-463 MHz. This is of particular interest here in NZ, as we've a legal 50 kHz wide unrestricted SRD spot at ~458.540 MHz that allows 100mW TX power.

The (May 2013) data sheets for their DRF4463D20 show this more traditional & easier to use module covers 410-440 MHz. However it's much more costly (US$19). Stan.
 
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srnet

Senior Member
By chance Mark has just informed me of a sleek new SPI linked SI4463 based 433 MHz DRF4463F modem module that has amazing RX sensitivity & data speed. Yikes - it's only US$6 too !
Click to expand...
I raised a query on the SiLabs Forum, the 'Wireless Team' say that the Si4432 packets should be compatible with the Si4463 packets, assuming suitably configured.

The consequence of this is that if the 5dB claimed extra gain of the Si4463 is realised, then thats an extra 5dB for the 'PICAXE in space' downlink budget, which could make a significant difference.

Has anyone seen sample code for the Si4463, its not driven using the same register map setup as the Si4432 ?
 
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MikeM100

Member
UK RF Modules

Don't forget 'easyRadio' RF modules from www.lprs.co.uk.

Simple serial in/out interface very well suited to PicAxe.

These modules are designed and manufactured in the UK and are available direct or from Farnell or RS !
 
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manuka

Senior Member
Thanks for the LPRS Easy Radio link - which few PICAXE'ers are probably aware of. As a "down under" South Seas resident I may be naturally Pacfic orientated,but the LPRS product range seems rather more costly (typically x2 or x3) than equiv. modules from Dorji etc. RX sensitivity may be an issue too? I've not knowingly worked with them -anyone in EU/UK care to enlighten ?
 
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manuka

Senior Member
Two simple tweaks for Dorji's popular & dirt cheap entry level DRA886RX dumb ASK receiver module herewith.

One tackles header pin alignment (the end pair annoyingly are not quite correctly positioned), the other RSSI tapping from the module's Synoxo SYN470R pin 13 CAGC. A DMM on DC volts to this point readily shows a ~1.2 V variation "inversely" related to received signal strength. Values ranged from ~1.3 V when the receiver was right beside the (25mW Dorji) transmitter, to ~2.5 V with no signal. This was with a high impedance DMM- avoid cheap lo-Z meters (with insertion resistance ~1 MOhm) as they load the circuit too much. Naturally a transistor buffer however could be used.

I'd initially favoured a DMM for DF (direction finding) work,as it's resolution allowed very fine mV level changes to be readily related to antenna tweaking,alignment or cabling. Propagation range changes or even simple "beam breaking" security (as path attentuation occurs) are also possible. The later was found good for ~300 metres across a park!

But such a tempting RSSI tap (undocumented) is very PICAXEable of course - local Andrew "Brightspark" mentions -

I do not like tacking on flying lead wires but an extra pin could be added to the 4 pins when setting up the Dorji as it usually comes with the SIL pins NOT soldered on (in my case) so you could ad a 5 pin SIL at the business end of the Dorji with one protruding under!?

The whole object has been to READADC simply and directly with least fuss the RSSI value direct from the Cagc line. = One Wire project The 10~50 MegOhm input impedance of the PICAXE pin is not likely to upset the radio This has least impact or issues or risk of loading the RF Rx superhet radio or causing any effects NO PARTS = One wire and a readadc 1, b1 command.

If you wanted to drive a moving coil meter why not use the PWMOut to scale and buffer the readadc value in software ? Squelch is also a great idea... It would be a s simple as saying 'if b1 < 100 then 'threshold of squelch".

Gating the radio for super battery life with the Dorji is all there and waiting since you have the enable pin to * Turn on the radio (low 4) etc * Sniff Cagc level * If b1 < 100 then (there is activity on the channel so time to wake up) *Keep squelch open or go back to 'sleep for x' If you want to 'fox hunt' then just convert the Cagc voltage to a pitch change and or pulse of the sound command to make it beep faster and at a high pitch as you get closer to the target etc...
Click to expand...
Stan.
 

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manuka

Senior Member
News just to hand from Dorji's man Mark: Hold on those PCBs ! Dorji's entry level ASK receiver module is about to be updated, with a different RFIC being used. Details yet to be announced (although it's rumoured akin to one of these?),but performance is apparently superior & price lower. Mmm-those inbuilt Manchester coding & ~3V versions appeal! A matching TX is also in the works,although it's less likely to be released.

Dorji rightly consider these ASK modules as small beer (or the Asian equivalent !) & are presently heavily promoting their swish SiLabs based DRF4463(F) transceiver module(s) for professional & commercial users.
 
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