Built Voltage Sensor with two resistors for Arduino with code and formula to measure any DC voltage

[@conversationwithgod272]

HI, THANKS LOT...NICE EXPLANATION AND I TRY IT AND IT WORKS PERFECT.

[@robojax]

You're welcome!

[@shivakotcherla627]

If I want to mesure milli volts which resistors I have to use ....?

[@edgarmastache1024]

Hello, thank you for the guidance, maybe I didn't understand it, so is it possible to read positive or negative voltages with this circuit and code? That is, in the event that I want to read the voltage of a pair of cables that I do not know which is positive or negative, will I obtain the corresponding values like any voltmeter? greetings

[@robojax]

Hello, No you must respect + and -. you will not be able to read if the polarity is reversed. the othe roption is to add two diods on the path of your device under test and about 0.7V is dropped, compensate that voltage in your calcualtion by adding 0.7V and you should get the correct reading but you won't know if it is negative or positive. or connect diode on the negative source and connect it to ONE input and compensate the 0.7V and positive into other input.

[@inductr]

Hello ,Thank you. I had to try some calibrating in the code and changed this** to set an offset "-const float arduinoVCC = **4.69;//Your Arduino voltage" works well so far. Any other ideas for calibration after all correct real resistance values are set pr instructions?

[@electronic7979]

Faydalı bir video olmuş. Ayrıca Türkçe altyazılar ve video açıklamaları da çok güzel

[@robojax]

Bana bildirdiğiniz için teşekkür ederim. Çok zaman geçirdim ve çok iyi olmasına dikkat ettim. evet ayrıca altyazılarda zaman harcadı. Hayırlı Ramazanlar.

[@electronic7979]

@@robojax haklısınız altyazılar çok zaman harcıyor ve çok emek istiyor. Elinize ve emeğinize sağlık. Hayırlı ramazanlar.

[@gep8639]

dear sir you are Genius

[@michaelshakib7777]

Thank you. Could you tell me if you have a video on logging this data?

[@robojax]

Sorry I did not understand what you are asking. Which data? eveything I have done is shown in this video.

[@michaelshakib7777]

I want to measure the voltage of my leisure batteries. I also want to log this data over a few days so I can see their performance. I am looking at your sd card data logging video and trying to figure out the code @@robojax

[@robojax]

You posted a link. KZbin is treating it as spam and I do not allow links unless you pay. So your comment with the link is not viewable to others. it is waiting to be delted by you or remove by me or approved by me.

[@michaelshakib7777]

Ok. I can delete it. How can I get the link to you? I dont mind paying.@@robojax

[@saikatd9037]

Can this voltage divider be used in card or bike as input

[@robojax]

If that input need up to maximum of 5mA if you use multiple output from arduino or 10mA if two or three outputs.

[@saikatd9037]

@@robojax I'll make custom RGB light pattern for bike

[@whiteggs]

Can you run 2 or more of that circuit at the same time on the Arduino? Example: read the voltages of 2 battery cells separately at the same time.

[@robojax]

of course you can. if you watched the video, then you know we use only one Analog input. you can do as many input your arduino has. Like Arduino mega has 12 inputs. Just use different input pin.

[@nicolassii7362]

how if the input contain high current for example 10A? is that safe for using same method?

[@robojax]

may be you did not understood. The capacity of course voltage does not matter if it is 10A or 1000A. The resisteros you use will determain the current just check the ohms law. Put the values and see the current.

[@himanshujana6665]

Hello RJ, Cloud you please clarify my doubts. As per the R2 formula, when i am measuring 36v , the R2 is coming 31k, but you mentioned 33k ohm's.

[@robojax]

Hello, o don’t remember what I said. Please watch again.

[@muhammadisa6954]

Thank you sir for the knowledge video. I can do it smoothly, but can you help me to mix the code so that I can measure voltage and can monitor voltage via gsm sim800?

[@paulpixzy5297]

What is normal zener diode and resistor tollarance?? Please help

[@robojax]

the Zener diode that you purchase, will have a datasheet. look at it. here an example of a datasheet for Zener diode www.onsemi.com/pdf/datasheet/1n4736at-d.pdf

[@radenadrianrafliprasetyo2594]

is it safe to use voltage divider to measure voltage in lead acid battery car when in use? is there any huge current going through mcu?

[@robojax]

Yes it is safe. Current has nothing to do with Arduino as it is not passing from Arduino

[@DanielPradoBurgos]

In Costa Rica where I live, I can't get diodes with 2% tolerance 😢 would it still work with ±5% tolerance? I need to measure 18v LiPo battery and was able to get ±1% resistors, would it still be fairly accurate?

[@DanielPradoBurgos]

It's a 1W diode it's the only thing

[@robojax]

Yes you can and the error would be as much as your component have. Try ESP32 with 12bits while Uno is 10bits so you get like 4 times more value and accurate result. I have video on eap32.

[@mahfuzurrahman678]

Can reading negative voltage?

[@robojax]

Only 0 to 5V.

[@sachiniganeshwaran8988]

Hi Sir! How do we do this using a STM32 board

[@robojax]

Hi, just find out how to read DC voltage. then apply the same principle. it need totally different code but principle is the same. Use my formula to do the calcualtion as I explained in the code.

[@newl.k.d6653]

sir how to conet 230v ac 220k.ohm and 5.1k.ohm dc input how to conet 230v ac input

[@robojax]

this is about DC only.

[@whiteggs]

Can it measure the voltage of a lipo battery from 3.2V - 4.2V ?

[@robojax]

I think you have not watched the video and not even read the title of the video. it says "any DC voltage" so it means yes. please watch to learn and use.

[@MuhammadLiaqat-s5c]

sir can use it for 700dc voltage

[@robojax]

Please read the title. I said “any dc voltage “

[@fizziergaming]

Hello sir great video my question is I measure 42 volt DC but the problem I measure the DC motor voltage that is 42 DC the problem is the DC motor run clock waise and anticlockwise direction is there are a circuit plz tel me

[@robojax]

If you are controlling the speed of motor using voltage, then you are doing it wrong. You should use PWM which will not waste any energy. You may measure the voltage before the controller.

[@RoyAndrews82]

Hey RoboJax. Why does the readings change (9.96, 9.97, 9.98, 9.99, 10.0, 10.02, 10.03) If no user interaction is happening?

[@robojax]

Hi, Analog input has resolution of which ignores certain values. When you use a resistor with ±5% tolerance, then the value will fluctuate about ±5% and so forth. for 8bits you can read any value greater than 5mV (or something I forgot the exact value. I might have mentioned it in the video) if you use a board with 12bit Analog resolution then you can reach much better value. So the analog resolution of the board and your resistor causes this fluctuation. That's why you need to average the reading. Also reduce your expectation like read only 10mV or 20mV minimum if you have low resolution board or cheap resistors.

[@RoyAndrews82]

@@robojax Okay, Thank You RoboJax.

[@ElectronicIngDiaz0786]

Excellent. I have a question: What is the zenner diode's voltage?

[@variantpixel]

5.1v

[@robojax]

Thanks. Bruno.

[@ElectronicIngDiaz0786]

@@variantpixel Thanks you very much

[@ahmedalzaidy8664]

Could you help knowing how to measure AC 220V or more and read the seven segment

[@robojax]

I will make video on that. But you can just add bridge rectifier with capacitor to convert it to DC then use this project and it should work.

[@OmarAlejandroPérezPérez-f6f]

Hello, one doubt, How can I be more exactly in my measuring?

[@robojax]

This is measuring about 10mV and if you need more accurate readings then used 12bits or 16bits ADC module.

[@luqmanhakim3675]

if i want to display at lcd 16*2 the value of volt that i measure ,just insert the coding lcd right?

[@robojax]

Here is video for that kzbin.info/www/bejne/ipOvlXSHpapnoKc

[@luqmanhakim3675]

@@robojax can you show that how to display volt with blynk

[@luqmanhakim3675]

Sir..i use this coding for esp32..then when i measure it is not getting the same value of volt..can you upload video measure use esp32 with resistor sir..Tq

[@arhamupadhye5157]

Hii what if I don't want to use any resistance or voltage divider, what changes do I make in the code??

[@robojax]

Hi, then you need basic reading using AnalogRead which can read maximum 5V. you can learn it from this video kzbin.info/www/bejne/raaxo62Hbdejj9k

[@arhamupadhye5157]

Thank you for the reply...

[@josephdada8434]

Thank you for this tutorial. Please, if we are to use this project to measure AC voltage, what of the current from the AC e.g 10A, wouldn't it be too much

[@robojax]

You are welcome. Here is the video for 50A to 100A AC and DC but see the code, you will see list of all other models for kzbin.info/www/bejne/aXSWZHemmLiqf9k

[@josephdada8434]

@@robojax Thank you, I have watched it. It means I need to change the module to the one that can handle higher current and rectify the 220 AC 10A to 220 DC 10A. But if am working with this value of AC which I rectified to DC, what value of the current will I use in formula to determine the R2?

[@josephdada8434]

I really appricate you sir

[@arhamupadhye5157]

Sir, how can I display the voltage values on TM1637 module. When I am trying to display it on TM1637, it is only showing the integer values and not the decimal values.

[@robojax]

TM1637 is junk. see this kzbin.info/www/bejne/apKmmHuEf9Fsobs where you can display anything

[@0124akash]

This code is best for LCD and serial monitor, but fluctuation reading on blynk webpage, why sir ? How to solve this problem?

[@isharanayanajith2017]

After upload the cord without any supply input there is a value shown in my serial monitor .please can u slove this problem..

[@robojax]

then it seems you have not watched the video and simply used the code. it won't work. you need to understand it. Please watch fully.

[@prashankpoojary5373]

Sir how to do the same for esp32 devkit v1? Can you please help me out.....

[@robojax]

Search my charnel

[@abhyu1112]

Make complete video on wcs1500 current sensor..as very less information is present on web ...good sensor for solar energy meter and in ebike application...

[@robojax]

You mentioned this before. The sensor is no better than anything else. just expensive. if the manufacturer send it I will make video of it.

[@yakupgulses9327]

Thank you for the first video I have a question. Can we do this with opamp?

[@robojax]

I am sorry, what do you mean by "do this with opAmp?" This will measure voltage of any point within the range. But opAmp is mushc sensitive and measure even less than 1mV like microVolt.

[@yakupgulses9327]

@@robojax Apart from the voltage divider I want to say, can we get a voltage divider with opamp?

[@robojax]

OpAmp has voltage gain but if you are looking for negative gain, do a Bing or google search .

[@belleluze]

@@yakupgulses9327 Use a buffer just hook up inverting input to output then use the noninverting as your input. note that you still need your divider and 5v Zener

[@danielbob7769]

We are waiting for a same project on esp8266. Good luck on your work !

[@robojax]

it works for EXP8266 and ESP32. there will not be another video as this is the most complete video. Watch carefully the code section.

[@danielbob7769]

@@robojax I managed to measure using your code but I had to introduce 3.05 V instead of 3.3 V as Esp8266 has. That's the only way it works. I measured with a mini code the voltage that A0 reads and it is 3.04 V . I used this value in my code and it reads with an error of maximum 0.1 V which is very good for voltages between 1.2 and 5V. I will also test with higher voltages. I have another question for you, I would be happy to answer : what Zener diode do you suggest in this case? For 3.3V or 3.1V (3.04V in my case)? And to size the voltage divider for VR1 = 3.3V or 3.04 V ? I used R1 = 7.5K and R2 = 29.8K. V R1 was 0.78 V for Vin = 3.9 V. Can I exceed VR1 from 1V to 3V or do I have to stop at 1V? here is my dilemma regarding Esp8266 . I apologize for so many questions . I didn't think you would respond to all messages so quickly. Thank you very much ! Stay safe ! God bless you !

[@robojax]

I am glad you were able to make it work. No worries about the question. I love to help if I can as I have full time job, family and other functions. So sometimes I forget or can't replay. if you know the input voltage maximum, zener diode is extra. you should use very accuracy zener if you want to use. VR1 is always the operating voltage or reference voltage to analog input. good luck and God bless you too.

[@frankbakker3684]

Goodday Sir i have a question. i am messuring a max off 50 volt wit a output to 5 volts. It works with the resistors but they are getting hot, almost to the point off overheating, do you have a solution forthat ?

[@robojax]

Hello, if you followed the resistor value of 5kΩ to keep the current under 1mA, then with 50V-5V=45V, 45V should be dropped on the resistor which should be 45kΩ. The power of the resistor should P=IV, I=0.001A and V=45V, so P=0.001(45)=0.045W or 45mW. Most resistor are 1/4W or 0.25W. I assume you are taking about the larger value resistor and that is getting hot. Measure the voltage across it and make sure the power of the resistor is at least 5 times the calculated power value.

[@soulcityosts960]

Dear Sir, In future please do make a video on controlling servo motor using Pca9685 via nrf24l01 module and potentiometer

[@robojax]

Interesting. I just put it on my "to do" list.

[@avadhootgandhe8026]

I have 72V and 90ah will it work?

[@robojax]

72V is important. yes just set the measurment for 80V or 100V so you know the voltage never goes above that. the 90Ah has no meaning here. it can be 2Ah or 1000Ah.

[@electromind4183]

But resistors are getting over heated due to power loss when i tried to use it for my 6s lipo battery can you please help with this sir and also suggest me is there any another method to read voltage for lipo batteries

[@robojax]

of course they should if you don't pay attention to selecting values. if you use 5ohm or 10 ohm they will heat up. but if you select 1k or 100k, there won't be issue. Here is energy meter full video kzbin.info/www/bejne/pabJdZVtdtmphM0

[@electromind4183]

@@robojax thanks sir , yes i selected 50ohms and 440ohms. So now i have to select in kilo ohms

[@Jarry519]

Thank you for this tutorial. please make ac voltage measure from 0-500 V with ardunio

[@robojax]

There is. Perhaps you want to make energy meter . I have written Liberty and demonstrated it. Please search my channel

[@tagolimotmarvin2243]

Can I used a 5% tolerance resistor?

[@robojax]

Yes you can. You'll get 5% error in your reading.

[@tagolimotmarvin2243]

@@robojax Thank you for the reply, how I can address this error sir?

[@robojax]

you are welcome. Watch the video and you will get the answer. I made the video to answer such questions.

[@tagolimotmarvin2243]

@@robojax thank you so much, i've learned so much from you, you are a great teacher.

[@newl.k.d6653]

how red led on 12v and 7.5v blue led on

[@robojax]

Your question is very basic. Start learning from my $200 course on udemy which is offered for free now kzbin.info/www/bejne/Y2fUhKV6iqZol5o

[@robojax]

Or hers is the playlist of the course kzbin.info/aero/PLHvJ4bw0xno4Z3FC2W07I4D2UP14bOaT2

[@newl.k.d6653]

tnx

[@depup2404]

As already said again nice video, but i still dont get it, what u did in your bargraph video was that from the viper of the potentiometer you measured voltage( but i dont have potentiometer but i have variable voltage 0 to 12 volts, can i do something like only take voltage - and + (higher then 5 volts) and display it on arduino and then display it on lcd from 0 to 12 volt. Thanks again.

[@robojax]

First use this video to able to measure the 12V . Ince you did, add or combine both codes together to see it as bar graph

[@depup2404]

@@robojax oh right thanks

[@sujitkarmakar2098]

Sir, thanks for your tutorials but in my project i am facing one problem and looking your guidance on this regard, I make on LCD DC meter to read voltage 0 to 40 Volt and used resistance divider ( 100K &10K ) to scaling up and for current use ACS12, 5amp sensor, but its display continuously rolling up even neither change at input. So i am looking your help to overcome the problem and suitable code for DPM voltmeter.

[@robojax]

This video is focusing on voltage measurement. See this video where it displays voltage kzbin.info/www/bejne/rnnIaoWIhryAeK8 but also has current, you may learn from it. But if you want to use ACS712 to display the current , here is the video kzbin.info/www/bejne/oau7oKiJr9uWppo I can't help you to put them all together. I made the video so you learn. watch them 2 3 or 5 times until you know how they work. I never skip the details so if you pay attention you will learn. good luck.

[@sujitkarmakar2098]

@@robojax thanks for your help..

[@robojax]

You are welcome

[@dominickd9291]

what about +/- 12volts?

[@robojax]

you gotta use a bridge rectifier, convert it to DC and than measure.

[@dominickd9291]

@@robojax I do not mean A/C signial, but an analog voltage that could also read negative? Couldn't this be done with only a few diodes before the divider?

[@AT_Eng]

can you plz show, how can we plot the voltage graph on android using hc05 ? Thx in advance

[@robojax]

wow. it needs developing reading voltage and feeding it to Bluetooth. then developing app that reads the voltage and plotting it . lots of work.

[@AT_Eng]

@@robojax there are already some apps i.e seialize Bluetooth and Bluetooth serial plotter, these 2 i know but there are more, can we use them?

[@himanshujana6665]

Hello RJ how can i get the complete Arduino program.

[@robojax]

What do you mean by “complete program “?

[@sreeharipksd9671]

I want check car battery Voltage using arduino and the arduino should take/initiate some actions according to voltage level. Is this possible?? Can you help me??

[@robojax]

You need to start the course from here kzbin.info/aero/PLHvJ4bw0xno4Z3FC2W07I4D2UP14bOaT2

[@parsistech]

Hello. Thank you very much for your complete explanation. I saw the whole movie. Can you say that this circuit can be used for 500 dc volts? If the current of my circuit is about 5 amps will it not damage the resistors or Arduino? regards

[@robojax]

سلام علیکم امید وارم خوب باشید. بلی که میشود برای 500 هم استفاده کرد. مقادیر مقاومت ها تعین کنندۀ ولتاژ ورودی اند. در مورد جریان باید بگویم که اید پروژه فقط هدفش ولتاژ است. اگر میخواهید ولتاز و جریان را باهم اندازه گیری کنید این ویدیو را ببینید kzbin.info/www/bejne/pabJdZVtdtmphM0 موفق باشید. Hi, yes you can use it for 500V. I mentioned also using a Zener diode suppress any voltage that is over 5V would also help.

[@parsistech]

@@robojax I was surprised to see your Persian comment. Thank you very much for your reply. 🤍🙏 سپاسگزارم 🌹🌹🌹

[@robojax]

سلامت باشی من فارسی زبان از خراسان بزرگ (فعلا افغانستان) هستم. از اسم تان حدث زدم.

[@parsistech]

@@robojax از اشنایی با شما بسیار خوشحال شدم. من هم متولد خراسان بزرگ هستم و در مشهد(ایران) زندگی میکنم. وجود هموطنانی باسوادی همانند شما مایه افتخار و غرور من است. برایتان بهترین ها را ارزو میکنم

[@robojax]

سلام علیکم. مجرا (کانال) فارسی علم و فن را راه اندازی کردم: لطفا به دوستان تان خبردهید و حمایتم کنید. www.youtube.com/@ilmofan

[@tharakarathnayake6760]

super excellent demonstration , and i would like to support u but i dont have a paypal , so how may i help to you ?

[@robojax]

That's very kind of you. I have paypal link under all videos in the description and on the page you get the code. But here is the link paypal.me/robojaxTV appreciated

[@MrBrymstond]

That's awesome!

[@robojax]

Thank you.

[@behappymike]

Hello, this is a great video however being a beginner I'm struggling to get the voltage reading correct. I have R1 as a 4.7k and R2 as a 220k as I want to measure a high DC voltage. I've tested the code on a 9v battery and the outcome is over 13v? any ideas would be most welcome! Sorry just to add, the resistors are 1% tolerance and the reference voltage is 4.5. All of the values in the code have been updated but I can't for the life of me get the right voltage out.

[@robojax]

Why you have 4.5V reference? I did not mention that.

[@behappymike]

@@robojax I've realised the power supply was only 3.3v so the 5v ref wasn't working. I've added an ads1115 which has a better resolution and now the readings are perfect 👍

[@ahmedalzaidy8664]

May God’s peace, mercy, and blessings be upon you. May God bless you and may Allah reward you for this good information

[@robojax]

Jazakallah. Same to you . Sukran.

[@dinamics2]

Why resistor are heating up

[@robojax]

Because you are using resistors less than 1k or 1000 ohm. Use higher values.

[@dinamics2]

Now its ok on 178k and 9.2k thanks

[@robojax]

Yes. I have mentioned it in video. Perhaps you missed it.

[@dinamics2]

@@robojax yes i missed it even watch complete video

[@janajankurova7683]

Thank you for this tutorial. It is great. I have a question above it. How I can measure DC voltage from another different analog inputs? This one was on input A0. I need mesure voltage in 4 (A0, A1, A2, A3 ) analog inputs together or 6 inputs together, where is different voltages on inputs. How will by the code above it? It would by statement .....Serial.print (getVoltageAverage(0)), Serial.print (getVoltageAverage(1)), Serial.print (getVoltageAverage(2))? Than you very much.. František, Europe, Slovakia

[@robojax]

Hello and you are welcome. I just checked the code and the getVoltageAverage() does not take any argument. It needs lots of changes in order to work with multiple pins. If you've watched the video, you would know. Perhaps I would have to make another video and the video will be ARDVC-02 but don't know when.

[@InnovationGuruSmartHomeSavings]

Kindly send the full codes of the program

[@robojax]

Hello, all my videos have resources page. The link is under the video in the description of the video.

[@robojax]

Did you find it?

[@InnovationGuruSmartHomeSavings]

@@robojax Got it

[@starlight_99]

demonstrate how can we measure 0.0001 volts accurately

[@robojax]

That is 100 microvolts. You need 16 bits ADC or higher to measure it. UNO is 8bits.

[@jonalddejesus6726]

can you please help me with my project sir,,I have a 12.6vdc connected on voltage sensor module (25vdc max )(30k ohms , 7.5k ohms),the output of the module is 2.5vdc ,and it is connected to A0 and GND of my arduino nano,but im getting a inaccurate reading on my serial monitor,Im getting a 2.8vdc reading on serial monitor,it is 0.3 volts higher than the output of the voltage sensor module using this code actualvoltage = (A0reading * 5volts)/1024;

[@robojax]

check the 5V voltage of Arduino and measure the resistors on the module. The best help is this video.

[@jonalddejesus6726]

@@robojax can I just connect the 5v pin of arduino to the Aref pin?and use the voltagerefference() function?

[@robojax]

yes and that is even better.

[@bylolo4964]

Merci Mr ROBOJAX

[@robojax]

Je vous en prie.

[@Jcal73]

Thanks for another great video! I have a few questions and apologize if they seem simple. I have a project that I want to measure the output voltage from a 48 volt 600watt dc power supply. What wattage of zener diode would I need to go with? The amperage will not be flowing though the Arduino, I just want to read the voltage output between the supply and a device. Thanks! Jeff.

[@robojax]

Hello, I just watched the video to make sure your question is answered. Indeed it is answered. Please watch without skipping if you want to successfully use Arduino to measure any DC voltage. By the end of the video you should not have any question left to measure DC voltage. As I mentioned this is for DC, yet people ask "can I measure AC voltage?" and the answer is NO.

[@Jcal73]

@@robojax Thanks for the quick reply! I re-watched the video and see it now. I must have just missed it the first time. LOL! I edited my question to change the power supply rating. I inadvertently entered amps instead of watts. I was able to order a 1N5993C from Mouser. www.mouser.com/ProductDetail/494-1N5993C/ I believe that will do. Thanks again! Jeff

[@robojax]

good luck. Yes that is the right Zener diode.

[@СБДТөгөлдөр]

250v ?

[@robojax]

Yes and 10000V BUT DC

[@solarchumboacido]

Like😊

[@hegazyhegazy3381]

can you send me that design

[@robojax]

what design? I've shown everything. the link to the code as I said in the video "you can get the code for this project by clicking on the link in the description which will take you to robojax.com slash learn slash arduino" There is not design. two resistor doesn't need anything. But if you want to draw it, you can use Fritzing free software or online using this tool easyeda.com/

[@hegazyhegazy3381]

Thank you

[@SharafatAli-ti9ph]

Laik 786 se 787 mene Kiya he

[@robojax]

?