Tinkering with: ADS1115 analog-digital converter

today's tinkering is accompanied by get up off of  that thang a soulful brown ale by devil may care   brewing in winnipeg i've had this one a couple  of times and i do really like it even though   it's not as heavy and dark as a stout reporter  it is a really good beer so today i'm going to   be tinkering with these ads 1115 modules that  i got in the last mailbag these uh for those of   you who were there at the time or have seen that  video these are a four port for input analog to   digital converter on the module we have power and  ground as you'd expect seo and sda so it speaks i   squared c it has an address input an alert input  which is optional and then the four analog inputs   this seems to be a really useful little board  so i think today would be an excellent time   to spend a little bit of time playing with it  and just seeing some of the use i can put it to   but in order to make use of it i'm going to  have to solder it up and i'm going to need a   micro controller to work with it so i'll have to  i think i'm going to choose a microcontroller that   doesn't have very many analog inputs  which would be any of the esp8266 or   esp family of microcontrollers but for this  i think i will use a d1 mini oh there's one   that's already got pins on it so a little  bit less soldering that i'll have to do   cool so i'll just quickly solder this guy up so  that i can use it and we'll come back in a minute all righty then here we have it on a breadboard  i've wired the i squared c seo and sda   up through a level shifter just a standard  level shifter board they're cheap and plentiful   that way i can run this guy off 5 volts rather  than the 3.3 volts that the d1 speaks so i can   get a little bit wider usage of this thing  measure a little bit wider set of voltages   so i guess the first thing to do would probably  be to find out what the i squared c address of   this thing is and to do that we will use just the  standard i squared c detect sketch what it does   is just quickly scan through all the possible i  squared c addresses that exist and reports back on   what responds on the bus in this case that address  is 4 8 not 48 because this is hexadecimal so it's   4 8. but if you remember there was an address pin  on that module so i think we should at least have   access to a few other addresses so let's just  take that address pin low and see what happens no change so low must be its default state okay in that case let's take it to  five volts and see what happens ah four nine okay so we got a  couple addresses to play with   that means we can have even more analog inputs  on our microcontroller excellent however   looking at the data sheet it tells me that there  is actually four possible addresses so if i take   that address pin to sda or scl i should get a  couple more addresses okay so let's try that   uh where is sda is there oh we got four a okay how  about if we try scl come on get in there 4b okay   so there is our four possible addresses so if we  can address four of these things and there's four   analog inputs each we've got 16  analog inputs we can play with   since i've got the data sheet up how about i  actually look at it a little bit here just so we   know what we're dealing with rather than diving in  all half cocked which is you know my normal mode   so the supply voltage can be anywhere from two  volts to five and a half volts it can have either   four analog inputs or two differential inputs  so measuring the difference between two voltages   simplify block diagrams so there looks like  there's a whole family of these uh similar   ones but this particular one the 1115 has 16  bit resolution and it has the most input pins   at that high resolution there's the  recommended operating voltages again the   supply between two and five and a half volts  full scale input uh up to six point one   four volts oh okay so it can actually measure  voltages higher than vcc which i assume means   that it's voltage dividing stuff down inside it  that just makes sense operating temperature from   ridiculous to ridiculous high impedance inputs  yeah okay data rates up to 860 samples per second   i don't know what else do we really  need to know here so it looks like   it takes the four inputs one at a time and  switches them through the pga which in this case   has nothing to do with pro golfers and it is not  as i initially thought a programmable gate array   it is a programmable gain array then it just  goes into the 16-bit analytic digital converter   and then out over the i squared c interface  i think that's about all we need to know for   what we're doing here right now this is all  fancy timing stuff if i was writing a library   this might be useful but i'm not writing  a library i am using existing libraries   and it appears that there are several libraries  to choose from you may notice i've got a couple   of them already installed that i'm playing with  so let's start with the actually there's one   more that doesn't show up on this page which is  the adafruit one so let's start there because   that's a convenient place that a lot of people  are gonna start there's a few things in the   examples that come with the adafruit library  that you can configure you can choose if you   want to use the 16-bit version or the 12-bit  version obviously i'm using the 16-bit version   and what else you can set the gain i'm just going  to leave it a default for now other than that   it just goes through does reads and computes  the voltages and then displays them like that   so i don't have any voltages connected right  now for it to measure so let's go and do that   let's just put one of them uh how about a0 over to i don't know how about the five volt input for  now i'll plug a few i'll plug these batteries in   as well why is that battery got two magnets  on it i love these little spherical magnets   by the way they are just so handy for doing  that with let's put that lithium ion on to a1   let's connect up this double a battery to  something about the third input sure and let's   just put an arbitrary voltage onto the fourth  input that we can change with this thing here   connect to ground what's it set for right now  it's set for four volts okay now let's go and   see what's happening well there we go we've got  some different voltages to look like look at   so let's just stop scrolling for a  minute here because these aren't changing   there are five volts in the first input  and that i think is the raw measurement   that it calculates out into an actual voltage  that is my half discharged lithium ion battery   that is my double a and that is four volts coming  from the power supply the library doesn't seem to   have a lot of uh fancy stuff going on but one  thing i do notice is it doesn't do anything to   address the uh the addressing it just uses the  default address which is what was it uh four   eight um but nowhere in this demo sketch or any of  the adafruit demo sketches it doesn't say anything   about that so i'm gonna move on to a different  library because i have many to choose from   so here's another one that's uh  fairly well rated in the listing   this one calls itself the white rabbit  driver and this is just the demo that   comes with it or one of the demos again just  like every arduino library there's one or more   demos that comes with it that shows off its  capabilities and this one allows you to state   the i squared c address by saying you've either  got it grounded or sent to vdd or to sda or scl   so you don't even have to know the numbers of  them it just just deals with in that way so this   one currently is set to ground let's let's  set it to use a different one just because let's go with s c l and i will  upload that and then we'll try it to just to prove that i squared c addressing  works duh we kind of already know that but   why not okay so when we bring that up we notice  it's uh just got the 16 bit to input maxed out   65535 a nice familiar number with it for anybody  who's ever looked at binary counting in the past   and of course it's showing that because we haven't  set the address line yet so if i connect the   address line to scl there and hit the reset there  we see that the values have all changed but this   thing again is showing raw numbers and i couldn't  find anything in this library's documentation   about how to calculate that into actual voltages  it's just the raw value coming out of the thing if you needed that that would be a fine library  to use but i'm not going to use it i'm going to   use a different one this library is called the  ads115 underscore w e library i have no idea   what that stands for um this one also deals with  the addressing and it just does it in straight up   numbers which is fine we already know what those  are in this example sketch has an awful lot of   different options in it all fairly well documented  right inside the example sketch which is   quite nice and shows what the  defaults are and everything else   this particular one is set up as continuous  mode there are a few other modes but again   for most of us i think continuous mode would  probably be the one you want anyway here's what   its output looks like again it's doing it in volts  so we got five volts on the first one which is   five volts coming off the usb 2.15 which  is my horribly discharged uh lithium ion   battery 1.23 which is a double a and four volts  is what's coming off my power supply and actually   let's vary that yeah i'm varying my power supply  and you can see that it's tracking very well   now this thing says it can it can measure above  the five volts so let's see that yes it can   there is six volts on the power supply but 5.57  seems to be the highest that it can do so just for   fun i thought i'd try it on a different processor  just to see how well does the libraries load this   d1 mini is an esp8266 this is an esp32 on this  olympics uh board that where'd i get this thing   from oh another maker sent this to me a while  ago so i will just quickly swap the wires over   i'm not going to bother removing that d1 mini  right now i'll just reconnect everything and i'll   get it right back to you here and there  we go i just threw the adafruit library   back onto that guy and lo and behold it  is showing exactly what we expected to say   and it looks like the five volts coming out  of that ole mx board is a little bit lower   is that correct yes it is 4.8 volts  is coming out of that not 5 volts okay   so it is correct cool and i mean there's no reason  why that shouldn't have worked right except for   libraries sometimes are a little a little finicky  but the adafruit library is fine with this esp32   and again any of the esp chips only have one  built-in analog input available so this just   seems like an excellent way around that uh  limitation should you need lots of analog   inputs so i guess the next thing to try is using  two of these together so connected up for voltages   i've got this potentiometer here between ground  and five volts that's going to the first one   the second input i've got coming from the 3.3  volts and the third one i don't have connected   anything in the fourth one i've got connected to  this old samsung phone battery which well let's   just see if it'll tell us what the voltage is so  i've slightly modified the sketch to address the   second one i'll take a look at that in a second  but i just want to look at that let's stop it from   scrolling for a second so the first four are the  same the five volt bus the lithium ion the double   a battery and the uh where is that coming from oh  yeah that's coming from the external power supply   then this one number five is the first input  on the second board which is the potentiometer   uh there's a 3.3 volts that's nothing and this  is that samsung phone battery let me start that   scrolling again and i'll adjust the potentiometer  so you should see number five changing here as i do that there we go so that is working how i had  expected it to most excellent   and here's the sketch behind it it is exactly  the same as the previous we library continuous   sketch that was the demo except for  i just made it a multiple so i just   duplicated a bunch of things in here i created  a second address created a second instance   and then just doubled everything up down  here set the com the comparator channel uh what else was i using here the measurement mode  is continuous as opposed to single shot i doubled   up on the read channel and then doubled up on all  of the printouts very straightforward i like this   library it seems to be for my level of coding  anyway the most user friendly the most versatile   i'm sure people who are more advanced that coding  will find some of the other libraries handy and   cool there is a bunch of  libraries to use for this thing   so i could go through and wire up the rest of them  but this kind of proves it to me and demonstrates   it to you and that's kind of the point of these  tinkering videos is mostly for me just to try the   different modes that uh that these things work  in and see if they will work with the various   things that i've got going on around here and  that i might want to do there are a bunch of other   modes that these things can do we saw it in the  library examples we saw it in the data sheet but   if i decide that i need to use those then i will  definitely uh explore those in the future but for   now this is the mode that i am most likely to use  this thing in if i want a whole bunch of inputs   and yeah the uno and the nano and some of the  other boards do have a bunch of analog inputs   the uno has six of them and the nano i think has  does it have eight it is yeah it has eight analog   inputs but they both speak i squared c so you  can add 16 more to them using these little boards   and i think that is going to come in handy in the  future some of you may remember this monstrosity   which is working towards a diy dmx project for  controlling lighting and the uh the setup that   i've got on it right now uses to i think it uses  all of the analog inputs available on that nano   so i could go much bigger if i chose to of course  i'll have to get more potentiometers but that's   minor i'm not sure if that's what's going to  happen but i'm still waiting for other parts   for this thing so that can be back on the  sidelines for a while and in the meantime   i think that'll do it for today um if you've  played with these things uh let me know what   uh what applications you found for them i think  i noticed in the mailbag comments a few different   people were saying that they had used them in the  past yeah i think it is a very versatile little   thing and if i can find more of them for the  really good price i got them for in the mailbag   which isn't the price that they are currently  but you know um i think i will make use of   them several times in multiple different things  anyway that's enough of me rambling um thanks   for watching everybody questions and comments  down below as usual i'll talk to you later

Channel: pileofstuff

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Length: 18min 29sec (1109 seconds)

Published: Fri Feb 04 2022