#18 ADS1115 Analog-to-Digital Converter Tutorial

let's see youtubers here is the guy with a Swiss accent again precise measuring of voltage is very important for many projects if you work with an Arduino you can use one of the built-in analog to digital converters also called a DC's this is very handy and in many cases a simple and cheap solution the resolution of these a DC's is 10 bit the biggest number you can use with 10 bits is the 1023 if your ADC has a maximum voltage of 5 volt one bit is therefore 5 divided by 1000 and 23 equals 4.9 millivolt so the smallest difference you can measure is 4.9 millivolt if you want to measure the voltage of a battery for example this is a very good sensitivity and if you use the method described in an earlier video you can get this resolution independent of the supply voltage you find the link to the video in the comments below but there are occasions where this method is not sufficient for example if you want to measure current using a whole sensor whole sensors create a voltage which is proportional to the current flowing through them they can measure current in both directions this is y 0 ampere is equivalent to 2.5 volt if you use the sensor with a maximum current of 5 ampere you can easily calculate the voltages the data she chose the sensitivity of 185 millivolts per ampere if you can distinguish 4.9 millivolt the smallest current you can measure with the built-in 10-bit ADC is 4.9 divided by 185 equals 26 milli ampair so your readings are 26 milli ampair 52 million per 78 million pair and so on no values in between are possible this is not very precise and for many applications not sufficient fortunately a simple solution exists you buy a more precise ADC for my purposes I bought an ad s1 1 1 5 it has a resolution of 16 bits so the biggest number you can use is 65536 the ad s1 1 1 5 has several modes of operation with different accuracies I use mode 2 which is comparable to the Arduino ADC it has a minimum voltage of 0.125 millivolt if we do the same calculation as before we get 0.125 divided by 180 five equals zero point six seven million pair as sensitivity so with this device we can measure down to less than 1 milliampere which is much better and in many cases sufficient the usage of this device is very simple because you can buy a module and the library exists you find the link to the source of the module and the library in the comments below but let's now check if our theory was right I use a 5 ampere hole sensor and measure its output voltage with the ad s1 1 1 5 and in parallel with a built-in Arduino ADC I use an Arduino Leonardo because I want to lock the readings in Excel as I showed in a previous video the keyboard mayn't function is very useful for this purpose the Leonardo Board can enter the numbers directly into an excel sheet you find the link to this video also in the comments below one important remark if you want to use the keyboard print function for your project if you start the Arduino it immediately starts to output characters and they are entered into your computer wherever your cursor is if you do not take precautions it is hard to stop the board because if you want to upload another program it destroys this program before you even can start the compilation or the upload not an easy situation the trick is to use a button to start and stop the keyboard entry only with this precaution the whole thing works if you include an if condition before the keyboard print commands you can read a button to change the status of this parameter like that you can put the cursor into your Excel window and press the button the Leonardo starts to key in the numbers and if you finished you press the button again and the Arduino stops keying numbers after that you can use your computer yourself usually I use LED 13 as an indicator when the keyboard print function is on but coming back to the reality check I used my bench power supply and increase the current from zero to one ampere here is the resulting diagram you see that the a ds-11 1/5 line is very fine and the Arduino a DC line is quite coarse exactly as expected I will use this ADC for one of my next videos where I try to measure wind speed with different method one method is to use a pitot tube the center of this tube also provides a very bleak signal I hope my new ADC can measure these signals with the necessary precision if you subscribe my channel you will be informed when the video is ready I hope this video was useful or interesting for you bye

Channel: Andreas Spiess

Views: 91,776

Keywords: Analog Signal, Analog-to-digital Converter (Invention), Arduino (Brand), Electronics (Field Of Study)

Id: tnfBslyfLRQ

Length: 7min 7sec (427 seconds)

Published: Fri Aug 28 2015