Navitron Renewable Energy and Sustainability Forum

Green Building and Design => Home Automation and Monitoring => Topic started by: ericw on October 20, 2010, 11:31:28 AM



Title: TX/RX pair for wireless remote sensing
Post by: ericw on October 20, 2010, 11:31:28 AM
Maplin are selling RX & TX modules (AJ58/9) @ 3.99 each which would seem to be useful for anyone contemplating remote sensing.
Looking at the datasheet they are relatively complex to setup, and will need a microprocessor to do it, but do seem to have a built in timer that can be used to kick things out of sleep mode into action periodically, so the system can have a very low standby consumption.


Title: Re: TX/RX pair for wireless remote sensing
Post by: EccentricAnomaly on October 20, 2010, 12:27:19 PM
Funny, can't find either AJ58 or AJ59 on their website at the moment.


Title: Re: TX/RX pair for wireless remote sensing
Post by: tim_h on October 20, 2010, 01:01:22 PM
Try A58J and A59J here: http://www.maplin.co.uk/Module.aspx?ModuleNo=267236


Title: Re: TX/RX pair for wireless remote sensing
Post by: KenB on October 21, 2010, 01:26:39 PM
Those are the same one that CurrentCost use in their electricity CC128 monitor. They are made by Hope RF Electronics in Taiwan.

Hacking the CurrentCost to use its display for displaying your own information might be possible - but Current Cost also do (on ebay) a dev-board that consists of the Hope RF module plus a small PIC16F???

Better value might be the transceiver module for 5.99  http://www.maplin.co.uk/Module.aspx?ModuleNo=267236&OrderCode=A60JN

This is the same module that JeeLabs use in their Arduino compatible Jee Node - so if you are looking for code to set them up and drive them - or brew your own wireless node - have a look at Jee Labs for their open source code.

http://cafe.jeelabs.net/


Either way - you will not be alone if you use this module  (1.226 million Current Costs shipped)


Ken



Title: Re: TX/RX pair for wireless remote sensing
Post by: EccentricAnomaly on October 21, 2010, 10:02:53 PM
Thanks tim_h.

Thanks also KenB.  Having looked at the datasheets I thought there'd be quite a lot which would need to be determined by experimentation (i.e., that isn't explained that clearly) so it's good to know that there's open-source code around that might help.


Title: Re: TX/RX pair for wireless remote sensing
Post by: ericw on October 22, 2010, 09:24:08 AM
Thanks for the information Ken, it going to be extremely useful.

There is some basic programming information on www.hoperf.com you need to go to RFM02 for the Tx and RFM01 for the RX.
The programming guides give examples of a setup unfortunately not for a TX that powers down and starts the micro an wakeup but I'm sure it can be done.


Title: Re: TX/RX pair for wireless remote sensing
Post by: MikeM on October 24, 2010, 10:12:00 AM
This could be cheap way to get some Hope RF modules with a PIC for free:

http://cgi.ebay.co.uk/Current-Cost-Development-Board-Pack-3-/180548999321?pt=UK_AudioElectronicsVideo_Video_TelevisionSetTopBoxes&hash=item2a098f1899



Title: Re: TX/RX pair for wireless remote sensing
Post by: KenB on October 24, 2010, 10:49:11 AM
Mike,

It's a PIC16F689 but I believe the RF module is transmit only.  It's preprogrammed with the CurrentCost (C2) wireless protocol. They use this board (or v.similar) in their Individual Appliance Monitors (IAMs).

It's set up as an analogue sensor channel which will send data to the Current Cost CC128 display every 6 seconds.   It sends analogue  readings - scaled in the range 0-500.

More details on Chris Dalby's blog   (Chris is a software developer for CurrentCost and a founder member/organiser of HomeCamp).

http://currentcost.posterous.com/

and this YouTube

http://www.youtube.com/watch?v=25s23uAH77g

Ken



Title: Re: TX/RX pair for wireless remote sensing
Post by: MikeM on October 24, 2010, 09:32:00 PM
Thanks for the CurrentCost links.

So, next question is how to convert Gas Meter pulses accumulated every 6 seconds into an analogue voltage that will be displayed on display as instantaneous Watts ?


Title: Re: TX/RX pair for wireless remote sensing
Post by: KenB on November 12, 2010, 05:13:41 PM

For hardware enthusiasts considering open source RF12:

Just heard via Twitter that Andrew Lindsay now has some code to connect the RF12/Arduino across to the internet using the low cost ENC28J60 ethernet controller.

This allows you to get data up to the web from your Jeenodes or home-brewed RF12/ATmega328 combination.  Good to see this particular combination of chips is starting to gain momentum.

Hopefully Andrew will be posting something on his blog soon.   http://blog.thiseldo.co.uk/



Ken