HomeSeer Temperature Monitoring

Contributed By Paul Giles  Using X10 and Homeseer my brother controls HVAC systems in his greenhouse but he had no way of monitoring temperature to make it a closed system. He asked me to find and implement a temperature sensor using homeseer.

There is an X10 module available but it is expensive and so I started my search for a cheaper alternative. After a lengthy search I located a website that sold a small interface that connected to the RS-232 port on a PC with connection for up to 4 temperature sensors. I placed an order for the unit at a cost of £30, it comes complete with one sensor but I ordered an additional 2. In less than a week the unit was delivered and I was surprised how small it was. The picture below shows the interface and one of the sensors with a 50 pence piece. I used a small PCB to mount each of the sensors and used a waterproof compound to protect from moisture.

When the interface and sensors were connected I used HyperTerminal to see the output. The next stage, interfacing with Homeseer was probably the hardest bit with a bit of trial and error and a lot of determination I eventually got there. First of I defined 4 devices in Homeseer, one for each probe. I then setup an event to run the script I had written every minute. The script reads the COM port for the temperature readings and updates the device codes.

I have now installed an interface on my own Homeseer but the temperature readings are not very accurate, if anyone could give me a clue why I would much appreciate it. As I am not a programmer my script will make a few people cringe but it’s not bad for a first attempt. Many users of X10 and Homeseer will probably come up with a few additional uses for this product.

SCRIPT
‘This script reads data from temperature sensors connected on com port
‘ and sets X10 device values according to the temperature
‘
‘changeable bits

‘==============================================
Const CommPort = 2
Const DTRstate = 1
Const RTSstate = 1
Const CommDetails = “2400,n,8,1”
Const DataMode = 0
Const Sensor1 = “k14”
Const Sensor2 = “k15”
Const Sensor3 = “k16”
Const Sensor4 = “k13″

‘=============================================

‘Default sub For The Script

‘=============================================
Sub main()

hs.CloseComPort CommPort
hs.OpenComPort CommPort,CommDetails,DataMode,””,””
hs.SetComPortRTSDTR CommPort,RTSstate,DTRstate
hs.WaitSecs 5
dim thisdata
ThisData = hs.GetComPortData(CommPort)
pos=instr(1,thisdata,”1 “,1)+ 4
roomtemp= mid(thisdata,pos,2)
hs.setdevicestring Sensor1, roomtemp
pos=instr(1,thisdata,”2 “,1)+ 4
roomtemp= mid(thisdata,pos,2)
hs.setdevicestring Sensor2, roomtemp
pos=instr(1,thisdata,”3 “,1)+ 4
roomtemp= mid(thisdata,pos,2)
hs.setdevicestring Sensor3, roomtemp
pos=instr(1,thisdata,”4 “,1)+ 4
roomtemp= mid(thisdata,pos,2)
hs.setdevicestring Sensor4, roomtemp
End Sub

Available From Quasar electronics, part no AS3145 Assembled Temperature Data Logger.

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