I have a Heating Unit in my Garage that is controlled electronically.
There are multiple Inputs/Outputs that I would like to "piggyback" and monitor.
I *obviously* want to do this safely as Mains Electricity is involved.
Inputs include Temperature of various points in the Boiler and also some form of sensor to detect flame in the Heating element.
Outputs are mains ( via onboard relays ) for Pump Off/On , Feeder Off/ON ( its a wood chip boiler ) etc.
I am the proud owner of an Arduino unit and would love to monitor what goes on i.e. Unit starts and only turns on pump at 50 Degress Celcius. I would like to monitor the data and can use Arduino to log this.
So my issue is *not* how to log the actual outputs to file/remote.
My issue is how to monitor the "on/off" and also temperature feeds from sensors safely. I did think about using a 240v "piggy backing" off the mains outputs to pump/feeder so this would turn on/off as the units would.
Hi Tpetar - good to see you again.
Can you shed more light on 1-Wire?
I found a 1 Wire temperature sensor Googling - One Wire Digital Temperature Sensor - DS18B20 - SparkFun Electronics but am not sure how I can use ?
The sensors are already in place and info displayed on Controller on heating unit. I basically want to piggy back and find out what goes on with the unit.
Cheers!
---------- Post added at 12:00 ---------- Previous post was at 11:58 ----------
Dont worry its optoisolated for much higher voltage then 220V!
Its safe dont worry, you can put twisted pair or some cable to transistor out from optocoupler, and use ohmmeter to se when is contact present (contact presend when there is main current on other side of optocoupler).
On high side be careful !!! Dont touch live wire with hands!!!
I give you picture, put resistor as on picture 47K and one diode. ;-)
I use 4N35 as shown in remote control over telephone to sense when is 220V device turned on or off.