extremely accurate digital clock

[getavinks@gmail.com]

how could i get an extremely accurate digital clock . i made a clock with ds1307 but the time is not that much accurate .

 

[kripacharya]

The accuracy of your system depends on how good your main time base is. In the case of DS1307 it depends on whether you have chosen a proper crystal for your chip, and its capacitive loading.

see this note for details --
**broken link removed**

Of course your measurement method for the accuracy should also be very good. How are you testing the accuracy ?

 

[getavinks@gmail.com]

in my clock with ds1307 there is a change of 10min in one week .
it may be because that my clock is placed in a room where machines are working .

 

[tpetar]

I think 10min is too much per week. In what temperature ranges you use this device (room temp, -20C +30C +50C 0C)?

 

[getavinks@gmail.com]

I think 10min is too much per week. In what temperature ranges you use this device (room temp, -20C +30C +50C 0C)?

the room temperate will be 20c to 25c

- - - Updated - - -

is there any other chip which is more better than ds1307

 

[ads_ee]

From another forum: DS3231

https://arduino.cc/forum/index.php?topic=87846.0

 

[kripacharya]

in my clock with ds1307 there is a change of 10min in one week .
it may be because that my clock is placed in a room where machines are working .

is your change an increase or a decrease ? does it go faster or slower ?
you can improve the accuracy using guidelines from AppNote 58, or go the easier route and use ds3231

it all depends on what you mean by extremely accurate

 

[getavinks@gmail.com]

extremely accurate means the time must be proper for around 6 months.
how is this ds 3231

 

[kripacharya]

extremely accurate means the time must be proper for around 6 months.
how is this ds 3231

upto 60 seconds in 6 months means accuracy/ stability of ~4 ppm. DS3231 datasheet claims to be able to do better than this with proper care in all matters.
i do not have personal experience with this ic however

 

[getavinks@gmail.com]

will the stability of clock chip depending on the code ?

 

[irfan ahmad]

ds1307 is best solution .

 

[BradtheRad]

in my clock with ds1307 there is a change of 10min in one week .
it may be because that my clock is placed in a room where machines are working .

This suggests you have access to mains AC. Is it reliable enough that you could use it as a timebase? Divide down 50 Hz (or 60 Hz) to get 1 Hz pulses, etc.