Checking if the air conditioning is on
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You could use a capacitor and an optocoupler. See http://www.edaboard.com/thread268348.html . Should be much cheaper.
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@kunall this is a wall mounted unit, not a ducted aircon. using temperature sensor present some obvious problems, like what should I compare the temperature to.
@Sparkman , yes this is the one i was referring to. OK, so its a mounting hole.... good!
I was aiming to detect the current in the internal unit, not the compressor (this is a multi unit system). the idea to hook onto the LED crossed my mind but these are new units, under warranty so I want something that is not invasive, if possible.
do you think the blower motor will produce enough magnetic field to be detected from the outside of the unit? I am not worried about the on/off cycle for two reasons. one is that these are inverter aircon so they practically run all the time and the other is that eventually the unit will kick in and I will get the alert.Thanks for the prompt answers!
Moshe@Moshe-Livne said:
@Sparkman do you think the blower motor will produce enough magnetic field to be detected from the outside of the unit? I am not worried about the on/off cycle for two reasons. one is that these are inverter aircon so they practically run all the time and the other is that eventually the unit will kick in and I will get the alert.
Hi Moshe,
Hard to know for sure as it depends on how far the blower motor is from where you mount it. I would get one to try and see. Are these units hard wired, or do they plug in to a standard wall outlet? If the latter, you could put something in between the plug and the outlet to measure the current draw.
Cheers
Al -
Hardwired, and they did their very best to prevent you from accessing the wires. I guess I'll have to wait patiently for the components to arrive.... Patience comes to those who wait, right?
How sensitive are those modules? -
You could use a capacitor and an optocoupler. See http://www.edaboard.com/thread268348.html . Should be much cheaper.
@Jan-Gatzke, this require to route the current through the optocoupler, right? I can't easily do that...
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No, it does not. You can connect it parallely to the fan.
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What about something like this?
@maltimus , this looks just right. I don't know enough to understand what is the difference between this and the modules on aliexpress. this one looks more refined, for sure but other than that I have no idea.... it does seems to be very sensitive if it can detect the difference in the magnetic field being closer to one conductor , so its promising!
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@Moshe-Livne It should be know what I have not worked with hall-effect sensors so anything I include to this post is purely my understanding from school/research. As current travels through a wire it creates a magnetic field around it. I believe these are so sensitive because both the current in and current out of the AC are so close together and there magnetic fields are cancelling each other out. If you are able to isolate one of the power cables it should be a lot more accurate.
Can you provide a link to the system?
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@Moshe-Livne It should be know what I have not worked with hall-effect sensors so anything I include to this post is purely my understanding from school/research. As current travels through a wire it creates a magnetic field around it. I believe these are so sensitive because both the current in and current out of the AC are so close together and there magnetic fields are cancelling each other out. If you are able to isolate one of the power cables it should be a lot more accurate.
Can you provide a link to the system?
@maltimus if by "the system" you mean the air conditioning unit, it is a relatively standard split unit with compressor outside and fan on the inside. getting to the wires is not trivial and will probably void the warranty, so non-intrusive is the way to go.
what i will do is wait for my stuff to arrive, and build a sensor and just see what it reads. as there is a large motor rotating on the inside i hope it will leak magnetic field. if not, there is always the LED.... -
Just a thought, those internal portions of the split system airconditioners have diffuser vents that open when the unit turns on and close when its turned off. You could fit a magnet to one of the vent blades, and use a magnetic reed switch to tell the system whether the vents are open or closed. That could be translated by MySensors as the unit running or turned off.
The plus side of that is that a reed switch costs pennies, and can be bought in a number of colours, so you should be able to colour match the aircon unit pretty closely. You can attach them with strong double sided tape if you cant screw into the unit as well (Use Automotive grade double sided tape, that they use for fixing badges on cars, works a treat), so it shouldn't void any warranties.
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Just a thought, those internal portions of the split system airconditioners have diffuser vents that open when the unit turns on and close when its turned off. You could fit a magnet to one of the vent blades, and use a magnetic reed switch to tell the system whether the vents are open or closed. That could be translated by MySensors as the unit running or turned off.
The plus side of that is that a reed switch costs pennies, and can be bought in a number of colours, so you should be able to colour match the aircon unit pretty closely. You can attach them with strong double sided tape if you cant screw into the unit as well (Use Automotive grade double sided tape, that they use for fixing badges on cars, works a treat), so it shouldn't void any warranties.
@Chester That is actually a great idea.... From what I read elsewhere it seems that the cheap hall sensors are not that sensitive so your idea should be the bestest... Thanks!!!
