[Music] hi there and welcome back to delali in today's video we will look at the importance of sleep mode in our electronics and Arduino projects we will also look at what modifications we can make to our Hardware to make it more efficient and consume less power come along [Music] let's take things from the top over here we have two 3.3 volts 8 megahertz Arduino Pro minis I have not made any modifications to the hardware so this is exactly as it comes right from the manufacturer I have uploaded
some code on there that turns on the onboard LED for two seconds turns it off wait 8 seconds and then repeat the cycle however this board only Waits For That 8 seconds while this other board sleeps during that eight second duration let's now take a look at the difference in power consumption or current draw [Music] foreign so this is how everything is wired in order for us to read the current consumption so the five volts from the power supply goes to the positive of the multimeter and then the
negative of the multimeter goes to the raw pin of the Arduino Pro Mini and then from the ground back to the power supplies negative this is the code I use for setup a and this for setup B the only difference between the two is I used a low power Library here and added one extra line of code for putting the ball to sleep for 8 seconds while this other one just waited 8 seconds over here on the multimeter we can see the board consumes 5.4 milliamps while waiting and about 6.8 when the LED is on so
we'll go ahead and write that down 6.8 milliamps and 5.4 milliamps let's now move the multimeter to this board once again we can see about 1.4 milliamps when the body is sleeping and 6.8 when the LED is on so we'll go ahead and record that as well after measuring the current draw between setup a and setup B we see that setup a saves four milliamps of current just by sleeping as compared to setup B that just Waits during that period to see how significant 4 milliamps of current is we would have
to use a duration calculator let's first imagine we use this 2200 milliamp hour 18650 battery for our test let's start with setup B giving a battery capacity of 2200 milliamp hour it had 8 Seconds of sleep or 8 seconds it should have been sleeping and consumed a current of about 5.4 milliamps so we change this year to milliamps and then the time spent a week is 2 seconds which it uses to turn on the LED and then from there it draws about 6.8 milliamps during that period so if we click calculate
here we can see approximately this battery which is a 2200 milliamp hour 18650 battery would be able to keep this board working for 387 hours now let's take a look at setup a [Music] giving that setup a also draws the same amount of current while awake or we need to change here is the Sleep current so we will change this to 1.4 and then upon clicking calculate again we can see setup a is going to last for 887 hours so this is more than two times the duration of setup B and this was achieved by s
leeping during that eight second period and saving 4 milliamp in the process further dividing the our values by 24 we have 36 days or approximately 37 days for setup a and for setup B we have 16 days so you can just see the huge difference between the two at this point we can stop this video here as we've seen the importance of sleep mode demonstrated however sleep mode is not just about adding extra lines of code to put the board to sleep when it's idle the overall efficiency of sleep mode is d
irectly tied to the external components of parts that make it into the final build of any project if we take a closer look we will notice that this green LED remained on throughout the operation of the board that means that this green LED contributed to the figures we recorded earlier in actual fact we programmed this led to Blink in between sleep and wake Cycles to let us know the board was receiving power and this can be replicated for any other project we do not need this green led to be on t
he whole time that said let's go ahead and desolder this green LED on setup a to see what the new current draw figures are foreign [Music] LED let's run the test again turning on the power supply we can see the system draws up to 5.45 milliamps when in operation and about 0.02 when asleep [Music] so we can see the significant jump between the 1.4 milliamp it was initially drawing to 0.02 just by removing the onboard LED and now I'm putting these new figures into the calculator software we can se
e changing from 0.02 during sleep and 5.45 when awake leads to a thousand nine hundred and eighty nine hours which is significantly higher than the previous value we saw during sleep mode and so dividing this figure by 24 we now have 82.88 or approximately 83 days and we can just see the difference between this and that kindly note that 0.02 milliamps is the same as 20 microamps at this point we have to ask ourselves is there anything else we can improve on this board and the answer as always is
yes we can improve the regulator we can swap out the original mic 5205 low Drop Out 3.3 volts regulator that comes with the Pro Mini for a 3.3 volt mcp-1702 looking at the data sheet of the mic 5205 that comes with the pro mini we can see that it's a 150 milliamp regulator if we take a look at the mcp1702 we can see that it's a 250 milliamp low question current regulator and by question current we mean the amount of current it consumes when it's idle and that value is 2 microamps which is signi
ficantly low so this is a much better regulator for our Pro Mini so let's go ahead and set up this regulator and measure the current values again at this point in the video it comes up will greatly improve my sleep quality for that here is a picture of my cut this is the schematic for the new setup so we have here our power supply the five volts from the power supply goes into the regulator and then out from the regulator goes 3.3 volts to the multimeter and then from the multimeter to the Pro M
ini and then back to the power supply and the regulator so that is that so now turning this on we can see the board draws a total of about 5.3 and when it's in sleep it draws 0.007 foreign this is equivalent to 7 microamps let's now put these new values into the duration calculator once again over here we'll change this to 0.07 and then this went lower so we change it also to 5.3 and after calculation you can see this figure moves forward even more further dividing this value by 24 we have 86 da
ys which is three more days than we saw previously at this point I believe we've seen the importance of why we should Implement sleep mode in our Arduino project and the need to pick our parts and components much carefully we saw that utilizing sleep mode alone in setup a saved as 4 milliamps and that's equal an operation time of approximately 37 days as opposed to setup B that would only last 16 days because it was just idle also by removing the onboard LED we're able to further reduce the Slee
p current consumption to 20 microamps which increased our operation time to 83 days and by swapping out the original regulator we were able to extend that 83 day duration to 86. you've been watching delali and it's been nice having you if you are new here kindly subscribe to stay in touch on how to design and build more cool stuff make sure to check out the channel and check out our other videos see you next time [Music] thank you [Music] foreign [Music]
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