How to use Allegro ACS712 AC/DC Current Sensor with Arduino

Hi, welcome to an Arduino tutorial from Robojax. In this video we are going to see how we can use this Allegro ACS 712 current sensor that can measure AC or DC current using Arduino. You can get the code for this project by clicking on the link below the video in the description which will take you to robojax.com/learn/arduino Let's get started with this. My Nam is Ahamd Shamshiri and I am presenting this tutorial from Canada. using this Allegro ACS712 chip you can measure AC or DC current. and that is the main important characteristics Hardware Explained this is the the module and that's a chip you can buy this as a independent chip or maybe bite of this module that if sold on eBay. And it has only three pins it works with 5 volts. You can connect the 5 volts here and then it has just an output so depending on amount of the current on this side if you look here the current passes through and there is a howl effect sensor detects the current and converts it to voltage so proportionally you get voltage from 66 mV per ampere up to 185 millivolts per ampere so for every ampere that passes through this you get a voltage here and you can even convert that voltage to a value that you can read it this way this can be used of a current sensor. This module is offered in 5 10 and 30 ampere. this is a 30 amp per version that we are going to use. the worth of this module is 13mm and the length is 31.2mm the height or depth is determined by this connector with the pin on the other side it will be 13.2 millimeters. Datasheet viewed (sorry for the wrong title) now let's have a look at the datasheet this is a low-resistance and that means that if 2.1 kilo volts or 2100 Vols passes through this is isolating your circuit from that voltage that you're measuring. The rise time that it can respond is 5 microseconds and the total output error is 1.5% at 25 degrees that's very important to know. 1.2 mΩ is internally conductor conductor resistance current passes here and that resistance here is 1.2 milliohm pin 1 and 2 is one pin of the connection and 3 & 4 is the other pin of the connection and this is the chip and this is a pin 1 on their side so pin 1 & 2 is the one terminal & 3 & 4 is the other terminal. so it would be connected and passes through this. As you can see it there so let me put it accordingly and then this is a VCC 5 volts will be connected to this pin and there is another filter between pin 6 and ground with 1 nF so they put also that capacitor here and for the VCC 5 volts also there is zero point 1 micro farad capacitor so that's a chip so all the capacitors the two capacitors are here and then because there is also an LED a power LED when you connect it it will turn on so they put a resistor for that and that's already there is nothing else on this module. this module is offered in 5 so this is 5 amperes 20 ampere or 30 ampere and the module is number is the same except the last portion which is 05 B and 20A and there's 30 and here are the rating that I mentioned plus minus 5 plus minus 20 which means it has no polarity in any way you can connect it because it can measure AC or DC and here are the sensitivities have 185 millivolts per ampere at 5 volts so this is more sensitive as I current increases we get hundred millivolts per ampere and 30A ampere it's 66 mV per ampere and here are the formula on how to calculate the current. and some characteristics and I've collected all these information and based on those I've written the code so We can measure the current and display it for us you need further details of this I will provide the link for this and you can Wiring Explained download and read it. And here is the wiring. supply the positive and negative positive enters(red wire) into the current sensor and the black wire exists these two goes to the load. because I wanted to test that with 30 ampere I put thick wire I still this is not thick enough for 30A should be at least 12 gauge wire but this is 14 gauge I put it and still be in series with your load. Here is explanation how you measure the current. let's say this is a battery or power source and this is the load for example in in DC this is a positive is connected to the load and from this side it comes to the negative and the circuit is completed. to measure the current you can put the ammeter either on that side or on this side just cut one of the wire and then put it so the current passes through the load and then goes through the ammeter and parameter will measure so this is called for the ammeter and series and then we put this module in series and a set of ammeter this is our meter so the current goes here and enters. we can put this on the top the same way. so this is how you can put this in series with the load to measure the current. here we have VCC this will be connected to five volts and then grounded this side I've connected the VCC which is a red one to five volts and then the ground the brown one is connected here to the ground and then the middle one which is out is connected to analog zero (A0) Code explained let me explain now the code that I've written. we have defined that VIN as analog zero A0 I will connect this to analog zero the V out or the out pin of the module will be connected here voltage that you are connecting for power supply is 5 volts in case it varies you have to enter it here. and then we have the model the model is the determining the characteristic as I mentioned we have 5 ampere 20 ampere version and 20 ampere and each has different sensitivity so this is the array and we are using the model and I have explained it as a comment here if you are using 5 ampere version use 0 just enter here 0 and if you have 20 and third one and if you are using 30 ampere use 2 - because the voltage is drived from the datasheet this is we are getting the quiescent output voltage QOV as I called it and 0.5 multiplied by VCC that you entered and this is a float voltage this variable that use internally and then inside the setup we don't do anything except plant this text initialize the serial monitor with 9600 baud if you want to see the serial monitor click on tools -> monitor because this is now not connected showing error. so now it's connected monitor and make sure that you are setting this accordingly because if you don't set this properly you will not be able to read the text. after that inside the loop() there are some calculations so this is a formula we are reading the A0 pin and then because the input range is 5 volts comparing it to 1023, 1024 steps we are dividing this and multiplying by the voltage that you are getting so we are getting the raw voltage and then the raw voltage you are subtracting the quiescent output voltage. This is the quiescent output voltage that we calculated here and then plus some error variation offset so you can experiment with your own module and change this or maybe just set at zero until you get the proper value and then this is the current. The current is calculated voltage divided by sensitivity of the model the model that you entered this is coming from this array so you do not change this array you do not change anything beyond this point and then we say absolute value of the current because if it's positive or negative in depending on the polarity or in terms of AC you see if the current is bigger than current limit I forgot to mention here I've set the current limit because if you're working let's say with 30 ampere or 10 amperes sometimes 0.5A or 1A will be neglected or it would not be your interest. value let's say above one ampere of 2 or 3 or 5 whatever so you set that one here and we are checking if absolute value of the current if the current is bigger than the current limit let's say you set it for one amp if when it's greater than one amp then we get the current but all in the meantime I'm trying also to print the voltage that is coming out of this pin subtracted from the supply voltage this is the voltage you don't need this it's just for reference purpose but this is the main one you get a current and we set it at two decimal place and on the screen and we plan the A at the end. if there is if this is not true then we just say no current and we wait five hundred millisecond and it continues like that Demonstration here is now the demonstration of this the power supply to this device is now three volts and in order to reduce the power I'm trying to use a lower voltage but the current is our concern so I'm gonna show you the three 3.2 volts and the current is now zero let me just change here and make it 5 ampere and then if I turn this on there's a serial monitor for 4.98 and this is the current that is showing through this device now. now let me just change it to 10A ampere. Let's go to 6 now it's 6 so that's the amount we can compensate for that because here is a 6 I'm just incrementing it with hand that is 7, 6.85 so you can see that the amount of compensation is that's 85 that's 150 milli ampere difference because with within 30 amperes that's very minimal but we still we can fix it. and where we can fix that is this and here so we can add some voltage in terms of fixing that so experimenting with different value I got at 0.12 so that's around 7 ampere so we are reading now let me just increase it to 8 see if we are getting that's very good eight and then pay attention here that's a current and this is what the serial monitor shows this is the current from the from the sensors. now let me incremented to nine so now it's around 40 milli ampere difference now that's 10 ampere it's very good 11 12 13 14 15 so that's 15 ampere 14.8 1 now still we are getting some deviation 43 watts I'm increasing the voltage the voltage should not affect it but on five volts now let me increase it to 16A. At 16 we are getting 300 less 17 18 19 20 now it's 20 ampere so around 400 milli ampere and now let me go for 23 so now this is at 23 ampere. now it's this is big difference now we are reading 21 let me see now the device is very hot because all of the current is passing through this. and this is too hot this is not made for 30 ampere. the module the chip is good for that purpose but the module the way they designed it cannot handle it it was extremely hot I shut it down now letting the module to cool down and then we will continue it from 23 and we will see if it can handle 30 ampere. we can set the amount of current that we will not look at let's say less than 1 ampere will be ignored 1.10 now it shows no current and I will ignore all those small values the device has the module is cooled down let me just turn it on what 23 ampere now that's very close to 23 still 450 or 500 milli ampere so I'm going now for 24 25 26 27 28 29 so 30 ampere we are reading almost, UFF very hot I just touched it it's extremely hot oh device become hot it reads incorrect value almost 700mA difference. tell you see it's correcting itself as soon as it gets cooler the correction goes and it goes towards 11 so now it's 11 enter the device is still a little hot but cooling down you see when I hold it in my hand the temperature drops and as you can see it's correcting itself meaning that this module needs to be cooled down or maybe designed better for the path of current for that reason it cannot be trusted above 20A thank you for watching this was introduction to Allegro ACS712 currents in search please subscribe so you can get updates of my upcoming videos and also if you have question or comment please posted at the description below I try to answer and reply Ahmad Shamshiri from Canada is thanking you for thumb up the video and clicking on subscribe . This is the least hat you can do for me. Thank you. you

Channel: Robojax

Views: 150,603

Keywords: electronic, drone, tutorial, training, video, robojax, arduino, code, download, allegro, current, sensor, ammeter, measure, sense, library, acs712

Id: DVp9k3xu9IQ

Length: 16min 46sec (1006 seconds)

Published: Sat Jul 14 2018