I’m looking for something that is able to determine if an electrical single is present or not through Linux perferrably.
The senerio I’m trying to figure out… I have a hydronic heating system and I want to be able to do some kind of reporting to which zones are requesting heat (I have 3 zones) and at which time of day, also comparitive to the temperature outside.
So, in the simplest broken down form, I just need a way to determine if the zone sensor is on, or if a signal has been sent to it. I know the voltage (24v) of the circuit and I have the temperature thing already solved.
Most of this is done in perl, I just don’t have a way to get the information to the system that the zone has been tripped by the thermostat.
So does anyone know of a way to determine or watch a eletrical circuit or query if the circuit is powered in Linux?
Alright so in simpler terms you basically want something that can monitor 3 different inputs for whether they are on or off?
seems like a $5 ADC would do the trick…
Parallel port, if your computer still has them, might fit the bill. You have 8 data pins and I don’t recommend fiddling with these. They are a bit more voltage sensitive, if I remember correctly.
But, there are about 7 or 8 status pins on the parallel port that can be kind of fun to tinker with (like printer ready, paper jam, etc). They source about 5v but don’t have a lot of power. I would think you could find yourself a reed-relay switch that can switch on 24v and wire the relay into the line some how. Granted, I’m a computer science kind of guy, not an electrical engineer so basically, I have no clue what I’m talking about and you will want to research this before doing any wiring.
The next trick would then be to persuade Linux to monitor the printer port for pin status changes. There is C code out there for checking the status bits on the parallel port. I would think you should be able to do this in just about any language that can grab the status of the printer.
I setup magnetic switches on my garage so I can check (from my PC or mobile device) if the garage is open or closed. I run it as a daemon under Linux.
If I could do it through Linux with some sort of serial/usb I/O circuit, I could easily do some reporting. I’m decent with Perl scripting.
What’s an ADC?
an ADC is an analog digital converter. you have some options. do you want to do any electrical work yourself? if so theres alot you can do the easiest being a circuit that matches your 24v outputs to the correct voltage level of the parallel port from which some linux c code can read the parallel port values. you could also buy a ready to go PCIO card which you can get that sits directly pin a pci port or a usb adapter. these can be fairly expensive and you still may have to do some electrical work depending on whether or not you can find a card that can handle 24v.
just do a google search for parallel port thermostat to see what some of this entails. theres tons of similar projects i found that you could look at just from google.