 Good evening everyone, I'm Stella and this is my this is our project just you know few of my friends you know make it like for energy monitoring so I'll be talking about for the goal and basic theory and the power measurement and the demo so the goal for this project is to give insight into power usage in our home so if we have this chart then we can if we know what we consume then we know what we can save so home energy audit and of course save energy but these are the read these are not just the reasons why I pursue this project it's climate change I think it's most likely that this is the reason why this project is being yeah so these are the two of my friends working on this project he's this is Kiran and the other other side is Peter there there yeah so basic theory you know that AC and DC DC is constant AC is coming back and forth so in power measurement there are three flavors this the apparent power reactive power and the real power to fully understand this I think this is the best analogy you have a mug so your mug is your mug is the capacity of your equipment and the beer is the stuff that you want this is the real power so the foam is actually the reactive power which does not do any work on the system for a reactive for a capacity sorry inductive load like motors reactive power is much greater so for instance I'm sorry for instance you have a motor rated as 200 kva at 230 volts if it's fully resistive this is the amps but if it's inductive it takes 108 extra extra current which goes into the magnetic the magnetic field of the inductor it magnetizes the motor which causes reactive power losses so of course we want to maximize the power so the left one sorry the right one is better than the left one yeah I'm a beer person so just a basic so to measure power in here we just need two parameters for actually this is the first iteration of this project we don't really we don't really mind positions for this one so it's just power voltage and current so this is the formula we're only concerned about the two because having one of these you can derive from from those formula so RMS and peak is so this is how you measure it using on-shelf equipment but yeah warning for the voltage measurement it can kill you this is the plug diagram basically you have a line 230 VAC at 50 Hertz so the circuit it has two circuits for the AC voltage measurement and the AC AC current measurement for this one we use the invasive Hall IC sensor but you can see from there that there is a isolator it is very important because this one is connected to the mains so without this here you possibly be dead if you touch anything on the board and this is your load in parallel so the circuit sorry this is just the current and the wave voltage and current wave forms that three combinations leading lagging current so this is a circuit so basically a amplifier so from here from the main for the main AC voltage we divided this equivalent to one ohm we just get a manageable voltage current levels and then we put it into a different amplifier so this is what you get so from a larger waveform you minimize it and then you rectify it to improve the resolution of your ADC you can actually analyze this by lifting to a DC but I think it's best if you use this so you can fully use utilize your ADC resolution and just a filter after that so it goes to the ADC 0 of the MCU for the current measurement is just also a basic amplifier it's a linear so you can get here from 0 to 1 you can see the power supply for the op amp is ground to positive supply so the idea of the Hall sensor is very basic you have a current current across a conductor generates magnetic field and you have a Hall element which actually translated into a voltage which is in here this is the signal output from the IC so this is the box that we made this is the oh sorry this is the MCU and this is the isolator apparently this DC voltage from the op amp got busted so we need to replace it during testing this morning and took out our 0 cross detection so we're unable to under-frequency it's also necessary because we want to do proper power factor measurement it's not possible without having that rate yeah and for the safety side use the serial to us be here with two opto isolators on the board just fully electrically isolated so yeah that's it and actually the next iteration with that would be we're not going to use the ADC of Arduino because it's 10 bit you might use arm M7 to do digital signal processing and all those stuffs for phase and other measurements so demo demo yeah look at it oh I'm scared wait just a moment so questions nice I don't think I have the usd putty in here you might want to use these htmi powering the using the bleeding power off to 30 volts to the outside of us yeah what's powered to a couple of old phone supplies in here fed from this power lead phone supplies 5 volt phone chargers just smashed a few cases you know yeah I do things like that I have a big hammer I don't have the axe anymore it had to go wait a minute what's done wrong it's not let me log in yet can I put it in here yeah sure this is the heckish fist pulse repairable so that none of the PCs actually work mediation oh I don't know why it's not playing both display show me displays I don't find they're not showing anything no yeah come back Linux all is forgiven no it's just it's just not doing anything it's keep a boy it's not working now it's just not going to play ball with that thing no well all I've got on screen is just a simple read out of voltages and currents anyway it's not a huge amount so but my laptop's not going to talk to this I'll tell you what it is it's jealousy it's all this AI and computer intelligence see today my programmer needed a new computer so we got a system with 32 gigs of RAM and now my little baby is jealous I'm going to have to bring it down to similar man treat us some memory it'll be fine switch to Mac how dare you we're going to have a seance an intervention we're going to pay to the great god Google to rescue you from Apple look I'm an Android fanboy don't talk to me my other Android phones over there in the bag anyway there we go so that's where we're at at the moment with this little device but it's also got a more serious side we develop air conditioners and we're going IOT with the air conditioner so we decided why not go to whole hog we're building our own power supply systems anyway so I thought well let's embed the full power measurement so we can monitor power quality we're going to be used on island resorts using solar power etc so we're able to monitor all kinds of faults from there I have a motor becomes faulty your power factors change we can detect things like that our safe operating area shut down if you're powering a tree phase motor and we detect power loss or brown out on a single phase shut it down before it burns out so there you go and of course we had to drag pork during into the project because he's the guy who's now programming our air conditioners and that's why we had to get new computer Android studio I hear Android studio okay there we go folks no but we do have one more toy to show does it use hdmi separate display audio omega and some approach for measuring our outcome system it also got a pressure sensor as well as humidity so you guys can take a look at it and of course we use shrink tubing to color code the probes and use the color display so we know which one is which I'm sorry we've copied up like foam inside now we tested that using one of the lab systems at NTU and it surprised us the tolerance on all but one of the probes was less than half a degree across the temperature range between zero and I think 70 degrees so it's much better than expected yeah they're standard NTC probes and the joy of using Arduino and Google nowadays we're able to google almost all of the code we needed and just tacked it together then he put the display code in a few other bits together so didn't take long now that's the simple one our main test air conditioner it's got 160 of those NTCs in it it's got 10 stm32 computers and nano and an arm board what are the why so many sensors it's a 330 000 atmospheric water generating unit and it's this one's a scientific instrument so it's a first prototype and of course when you're working with a bunch of scientists from NTU they love data they love to torture me with data okay anyone have any announcements