Wireless Temperature and Humidity

While waiting for some RFM12B’s to arrive so I could continue experimenting with jeenode,and variations, and Nathans veroboard wireless temperature arduino, I acquired a Quasar QAM-RX4 AM Receiver module from ebay and tried out a few experiments. One of these was with a wireless temperature and humidity module I had purchased after reading an article by Jaakko.

Quasar QAM RX4 AM Receiver

Quasar QAM RX4 AM Receiver

To me, one of the challenges we face is implementing our technology in a consumerised form.That is to say we can produce the electonics and code relatively easily, but even when we put the electronics in a case it still looks home made. Repurposing or hacking existing consumer items produces objects which are much more acceptable in the average home and to our families.

WS2015 base station and WT540 Transmitter

WS2015 base station and WT540 Transmitter

Jaakko’s hack is based on a decode of the wireless protocol by a Swede and a Norwegian, Johan Adler and Øyvind Kaurstad. Fortunately Jaakkos site is in in english. I replicated his hack of the larger base station with its separate receiver board. Unfortunately, no matter wether I used the on board batteries or powered the receiver from the Ardiuno I was unable to get reliable data reception. Maybe I needed a level shifter.

WT450H Temperaqture and Humidity transmitter

WT450H Temperaqture and Humidity transmitter

For various reasons I had to put this project aside. When I hooked up the 433Mhz AM receiver to the Arduino I tried out a cut down version of Jaakko’s code and after a bit of adjustment it is now recieving the data reliably.

QAM RX4 on a mini breadboard. Connect all pins, linking pins with the same annotation, see RX4 manual. Black and white wires are to the aerial. Data to pin D3 for interrupt 1

So, some points of note:-

If you use this receiver there is no need to buy the transmitter and base station, you never saw the base stations sensors on the Arduino anyway.

The transmitter that came with my WS2015H base station was the WT450, ie it had no humidity sensor, transmitting zero for this sensor.

The addon transmitter is the WT450H, ie it has both temperature and Humidity sensors.

WT450H on its mounting bracket with prop stand

WT450H on its mounting bracket with prop stand

The transmitter clips into a bracket which has a flip out stand and screw keyholes for wall mounting.

WT540H showing clip on bracket and sealed connector to the external temperature sensor

WT540H showing clip on bracket and sealed connector to the external temperature sensor

An external temperature sensor is supplied with each transmitter. When connected it replaces the internal temperature sensor

The transmitter can be set to any one of 15 networks and 4 channels. the base station can be set to any one network, receiving the four channels. Jaakko’s original code only decoded the first 7 networks. The network and channel numbers now match the network and channel numbers on the transmitters (rather than starting from 0)

The transmitter sends the same value 3 times in quick succesion once a minute. This is an attempt to ensure  that at least one uncorrupted message arrives every minute.

Serial Monitor results

Serial Monitor results

You can purchase the transmitter part number 36-1797 from any Clas Ohlson store for £7.99.(!)(A bargain, while stocks last, no affiliation, etc,etc.)

Be aware that while it looks like you can buy online, all you are doing is creating a list you can print out and take with you to the store.

Thw QAM-RX4 appears to available from the usual sources, Farnell, Rapid, + RF Solutions and Quasar UK. A minimum order value may apply. Other AM Receiver modules are also likely to be suitable, try it and see, then report back?

Here is a copy of the RX4 manual and a copy of the test program i was using which is based on Jaakko’s work


Nanode – 0547

Light Sensor 24 hour view

Light Sensor 24 hour view

My Nanode, serial number 0547, has been sitting on the window sill of the spare bedroom since the first week of september and has been running continuously now, apart from when we had someone staying over, since about the 14th september.

It has been running a sketch based on a combination of the many examples out there using Andrew Lindsay‘s Ethershield Library for the Nanode’s ENC28J60 and utilises the on board MAC chip, DHCP and DNS lookup for Pachube. Three analog inputs are being monitored and and the data being pushed upto Pachube. The feed number is 35364.

Light Sensor - 1 week view

Light Sensor - 1 week view

The three sensors were temperature, light and supply voltage and they are all breadboard mounted next to the Nanode. There is clearly something wrong with the temperature sensor, an LM35, but I have ignored it as I was more interested in seeing how reliable the nanode and sketch was. The light sensor is a simple LDR, and on the one week and 24 hour graphs, clearly shows daylight, night time and when the lights hve been turned on in the evening. The third sensor is a simple voltage divider with the value being x100 and shows the value to be between 4.98 and 4.99 volts

Not all gadgets need be electronic – 5

Velcro straps aka Velcro Ty-wraps

Quite a few years ago I ordered some Velcro ty-wraps from RS Components. They were new then and expensive and came “in any colour you like, as long as its black”. A clever use of velcro though because unlike conventional ty-wraps, they were open/closeable or reusable.

Openable velcro ty-wrap

Walking down the the electricals aisle in the local Asda, I see they are selling them under their own brand Status label, as “Velcro straps”. These come in multicolour packs of 10 for £1.75! Bargain!

xAP network nodes – Arduino and Nanode

The arrival of Ken Boak’s Nanode 5 board this year has prompted me to investigate the possibility of transfering some PC based functions around my home to distributed devices. In particular I wanted some to move some displays and data collection out onto my network.

xAPClock - a networked LED matrix clock

The first target was a ‘proof of concept’, a simple networked clock display using a 8 x 32 LED matrix. This is based on an Arduino, an ENC28J60 Ethernet shield and a 0832 red LED matrix from Sure (via ebay). Utilising the clock.report schema from an xAP NTP service on the network, Derek and Bretts xAP, xAPEther and EtherCard arduino libraries and Andrew Lindsays HT1632 library, this keeps its own time, resyncing to the NTP service at whatever interval it transmits.

xAPClock - breadboard interface to the Arduino

Moving on, I had earlier purchased a large, 6 inch wide, 20 x 2 LCD display. This has an hd77480 interface to which I have attached to the Arduino via a Byvac bv4108 serial backpack. This comes with its own Arduino Libraries. Again using Brett and Dereks xAP Arduino Libraries, this display defaults to displaying a clock as the LED matrix clock does, but also supports the message.display schema for general messages and alerts from other xAP applications and most importantly the CID.Lookup Caller Display schema from mi4’s xAP Switchboard, so I know which calls I can ignore….

Not all gadgets need be electronic – 4

So you’ve taken a fabulous photo with your digital camera and feel the need to print it out to show your friends and family. Great, eveyome loves it and is impressed.  But what then? Well your fridge or freezer could be the place for it.

Rather than just blu-tacking it on try a magnetic photo frame  like this one

Click on  the picture above to see this item on Amazon

This is a set of 3, each  6″ x 4″,  photo frame pockets, with fully magnetised back, and its only £2.08.

Apart from photos you could also use to insert paper with important reminders, or phone numbers, or a recipe

Home Automation – Telephony

I first got interested in home automation in 2003 when I bought a copy of the american program, Homeseer, then at version1.something.  I had great fun tinkering with it and some x10 plugin modules and sticky switches. One of the nice features of homeseer was the scripting language, and this together with an active user community encouraged me to work on a script  to collect CallerID information for incoming telephone calls.

The idea was to build up a database of names of incoming callers so that on subsequent calls the system could tell me who was calling, or failing that, by interpreting the STD code, where the call was coming from.

The available hardware to interpret the UK CallerID (different from the american version) was limited, the Pace Solo external modem, a version of the Zoom 3025c PCI modem, and the Meteor Caller ID box were pretty much the only choices. At the time the Meteor was the best, but also the most expensive, so I bought a Zoom  modem. My script monitored the modem, collected the data,  matched it against the database and an STD list, and then displayed it on an ASP page  on the Homeseer web server together with the date and time of the call. Associated scripts and ASP pages would display the information on a Matrix Orbital LCD and on a Customer Pole VFD display.

This setup worked pretty well for about two years until mid 2005. At about this time I became aware of xAP. The principal appeal of xAP to me at that time was that it enabled a distributed system to be created rather than the centralised model that Homeseer was using. In addition there was a huge range of useful looking applications available, both linux and windows based, and the tools to allow you to create your own.

One of the applications that immediately got my attention was xAP Switchboard from James Traynor at Mi4.biz. This is a Windows based database and associated web server designed specifically for telephony. When married to Kevin Hawkins’ xAPTel and a Meteor box this replaced my Homeseer system and provided a number of other features which far exceeded anything I could hope to achieve by scripting, including incoming and outgoing calls, call duration, database searching, differentiation of caller source by location or type (mobile, home, work,etc), multiple phone entries for a company or individual contact, Skype, dialing out, multiple lines (back then I had a fax line), etc.

Of course underlying all this is xAP, or more specifically the xAP protocol and its schema.  For instance it is the schema, in this case the CTI schema, which link the two applications, xAPtel and xAPSwitchboard together, so that the two applications don’t even have to be on the same pc.

xAP Switchboard Webserver - click to see a larger version

xAP Switchboard Webserver - click to see a larger version

xAP Switchboard responds to calls by matching the number and sending out its lookups using another schema CID.Lookup. Not wanting to maintain Homeseer for the LCD and VFD displays, I created applications in VB6 using xAPIntranet.ocx (also from Mi4,biz) to take the CID.Lookup data and display it on these screens.

When I started using xAP Switchboard and xAPTel, I imported the data I had collected on Homeseer, so that my telephone records now go back to 2003, and apart from a short break earlier this year when the pc died, it has been contiguous.

xAP Intranet enabled

xAP Switchboard is part of the xAPIntranet

There are many features of  the xAP Telephony subsytem that I do not use, but back in 2006 I attempted to document them in a diagram which is over on Mi4.biz. From top to bottom, we have the possible sources of information, with the database in the middle and the ways you can display it at the bottom. It is quite likely that over the intervening period there are additional items that could be added to this diagram .

Click on me to see the large version

xAP and Telephones - Click on the image to see the large version

As I said I have been using this system since mid 2005 and there have been no updates to the core software since the end of 2005, so I think we can call this ‘mature’ software. Certainly it is at the heart of my home intranet, and when it was not available I missed it a lot.

Not all gadgets need be electronic -3

Having a bit of an Ikea theme – if you were considering the purchase of the lap tray in the previous post, then you should also consider this laptop accessory, the Barda Laptop support.  Quite substantial and useful for  more permanent use on a table to make the keyboard more accessible,it has room for the power brick underneath.  Unbelieveably its only £3.49 currently  (must be on offer).

Brada Laptop Support

Click on the picture to go to the site (no site affiliation/benefit for me)