RTC (Real Time Clock) with Arduino - Low Cost MCP7940N

Here's a video on one of my new favorite parts - the MCP7940N RTC (Real Time Clock) because it provides a super cheap way to add time keeping to your projects. I've been using this part for a while now, but just now got around to making a video on it. Stay tuned for videos showing how you can use the alarm outputs to wake up from low power sleep states on the Arduino. Also, accuracy testing stuff will be coming soon as well...



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[jotchava]

Man, please never ever stop making these videos.

[georgebitsworth]

Why do you convert the raw data (which is stored in BCD) to decimal (actually you're converting it to binary). An example is if you don't convert it you can display the value of seconds with the command "Serial.print(rtcSeconds, HEX)" instead of "Serial.print(rtcSeconds)" and save a few lines of code.

[nrdesign]

I've had enough of the DS1307 and its quirks. I'm looking for a good alternative, and this looks very promising.

[AlleyBeachElectric]

just found this. Awesome content! I will totally be using this in an upcoming project. quick q- Why would you subtract 48 and not add in regards to the ascii table?

[garthhowe]

Thanks Kevin, this is another great reference video for future use. I like the details you include as they are essential to work on a project like this.

[reshadrei]

sir can you make a video that synchronize 2 clock by obtaining time stamp from gsm sim card

[alekovar]

great video, very detailed and very understandable, thanks Kevin keep doing this great job.

[DiyintheGhetto]

Hello Kevin There is a one arduino board that has a RTC build on board well it has a 32khz crystal on it. Te arduino zero pro Which i used recently i been using it as a RTC clock for 2 months now and have only lost about 20 seconds of time. that chip alone is only 2.95 then you need the crystal for it and other little parts so maybe around 4 dollars for all. But it does make a good RTC clock chip and cheap too.

[AlexAwwesome]

They made a comparison of DS3231, PCF8563, MCP79400, DS1307 accuracy. DS3231 is the winner.

[BoredT-Rex]

Will this clock adjust to time changes. I want to put it in a device, but idk how to update it if I seal it up

[regal_]

Absolutely amazing video. Thank you. The only best video I've found for using the Arduino with this particular chip. All other videos simply use the standard DS1307 module. I don't want to use that because where I'm from, an original part costs a kidney and an eye.

[rasmushaun]

Nice video (: I found it working for mcp79410 also (: what is the difference between these to RTC's? (:

[DuongTrongHue]

Great video. But why do you need include wire.h library in your code when that library is already built in Arduino?

[Tapperje]

Would these steps and info work with the RTC DS1302 chip?, i mostly have problems with mine now..

[edwardmallon]

Excellent tutorial as always Kevin. We've been using the DS3231 RTC's for quite a while now:


The eeprom that usually comes with the DS was my initial reason for going with that RTC, and this made me curious what drew you to the MCP7940?

[rondlh]

If you just want to wake up the Arduino sometimes, but don't care about the exact time, then you can do this without the RTC(C). There is a limit to the amount of time you can make the Arduino sleep, but you can just make it sleep again immediately if there is no action to be taken.

[kemoomotivation]

would the code work with th ds 1307 rtc . if not please can you adjust it .
most of the code i cant understand

[vonries]

I know I'm very late to the party but damn that's excellent work! Keep it up, PLEASE!

[pirateman]

At the risk of sounding stupid, what is wrong with using the DS1371 boards that are so cheap and readily available (~$USD 0.50)?
I don't see any difference in performance. Do any of you?

[deldarel]

does it take leap years and leap seconds into account?