Visualizing RF waveforms
30 May, 2013 - 01:22
Just something I've been playing with. I'm not sure its 100% accurate as I still need to compare what the real waveforms look like vs those I'm plotting from the data. Anyway have a play see what you think.
http://www.homeautomationhub.com/content/rfplot
UPDATE: Sorry about the email spam I didn't know page node had subscription notifications on by default.
6 June, 2013 - 21:03
#2
Great job Brett. This is the
Great job Brett. This is the one thing HAH was lacking for me, rf receive/decode capability.
Ive now got the urge to buy some random RF kit now, just to have a go at decoding. SWMBO is gonna be well pleased!
Garry
6 June, 2013 - 21:12
#3
Pretty awesome
The URF thing is indeed a very flexible beast. This latest set of tooling from Brett makes it easier than ever to visualise what is going on.
Of course, RF reception for the HAH has been available for quite a while -
http://www.homeautomationhub.com/content/homeeasy-rf-receiver
Onwards & upwards.
Derek
11 June, 2013 - 19:54
#5
Looks great Brett, what kind
Looks great Brett, what kind of RX receiver are you using? RFM12Bs?
12 June, 2013 - 00:36
#6
I'm using one of these CZS-4A
I'm using one of these CZS-4A by SZSAW
http://www.szsaw.com/old/En/html/product.asp?id=354
A quick google and I can see them in the UK too.
http://uk.shop.com/Alarm+Wireless+Remote+Control+Receiver+Board+CZS+4A-6...
I've attached an arial to mine to increase its range.
However any cheap 433Mhz receiver will do the job.
Brett
14 June, 2013 - 20:40
#7
Thanks, i suspected any 433
Thanks, i suspected any 433 would do the job :)
will have to have a play
Andrew
16 June, 2013 - 09:41
#8
Cost .vs. performance
Yup, pretty much any 433MHz module is good for general 'get something working' decoding. However, for 'production' use, where range and reliability are important, you might want to choose more carefully.
In the early days of RFRx work, I evaluated a number of 433MHz receiver modules. As you might expect, you generally get what you pay for.
The one that we sell in the shop is the 'best of breed'. It's certainly not the cheapest.
Lots of variables with RF Rx, especially if your home is awash with 433MHz devices and sources of noise. The use of a decent antenna with a reasonable length of cable & a magmount base made it easier to experiment with placing the antenna in different locations.
16 June, 2013 - 10:00
#9
Good RF device
If you are rushing out to buy some RF kit, I'd recommend the HE305 magnetic switches. They produce a good strong signal and can be configured to transmit on both a 'make' and a 'break' of the contact.
I've had these deployed for a couple of years. Batteries last around one year ... longer if the contact isn't broken terribly often - the fridge door one was the first to need replacement!
Also easy to pull these apart to produce 'custom' setups.
Creating URF strings is rather tricky.
So I've built something that will help out.
There are two components to this - An Arduino Sketch and RF Receiver to capture the RF waveforms.
Some backend Javascript to convert these pulse duration reading into URF encoding.
Step 1. Get the UniversalRFRx sketch -This is in my development branch (for now)
http://livebox-hah.googlecode.com/svn/branches/brett/userapps/arduino/Un...
Flash this to an Arduino and attach an RF Reciever with its data pin to Digital 3 - adjust the sketch if you want to put it elsewhere.
Step 2. Run the sketch with a serial monitor. Press your remote and see if the RF pulse durations are captures.
Step 3 Grab the output string.
From here you can PLOT and convert them to URF.
To see the pulse sequence: http://www.homeautomationhub.com/content/rfplot
To convert into URF: http://www.homeautomationhub.com/content/pulse-train-urf
The conversion uses a best guess kind of algorithm as its rather tricky to get this matched perfectly but it should be close enough. As I can't tell how many BURST are being emitted I default this to 1 so you'll need to supply some other number and re-pack. Probably say 10 or so you'll have to play around with the URF string and see how the receiver is liking it.
Anyway enjoy - I'm also working on a xap-urf backend so the HAH can also spit out xAP for ANY inbound RF string. Which should be nice and give us plug and plug for RF devices.
I updated the rfplot to be an embedded <iframe> now the mouse works on the plot to show durations on hover and you can pan/zoom with the mouse wheel and mouse buttons.
Brett