# specialized IC for real time clock

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#### sanjoy

##### Member
i want to make a clock displaying hh:mm:ss on 7-segment display. i find here DS1307 but as fer as i know, it requires a micro-controller for this controller i have to write program. unfortunately, i have no programmer to write program on chip. initially i try for 74xx IC but it requires many components.
so i find something easy to make which is specialize for real clock work in low voltage and also avaliable in indian merkets.
plz help me.
regards.
sanjoy

#### mvs sarma

##### Well-Known Member
i want to make a clock displaying hh:mm:ss on 7-segment display. i find here DS1307 but as fer as i know, it requires a micro-controller for this controller i have to write program. unfortunately, i have no programmer to write program on chip. initially i try for 74xx IC but it requires many components.
so i find something easy to make which is specialize for real clock work in low voltage and also avaliable in indian merkets.
plz help me.
regards.
sanjoy
you can have a programmer if are talking about program writing hardware, it can be made cheaply or purchased at some cost.
other side you need to learn software writing. any discrete design to realize a clock would be of more components, no doubt. there are PIC applications for time display. you can browse on Microchip.com application notes. AN0615b application is one such, and it works off 2 cells.

perhaps you need to do through research of Indian markets to be sale to be able to comment, Sanjoy !!!

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#### sanjoy

##### Member
im not looking for a PIC rather than a clock IC which has it all.
thanks

#### gaspode42

##### Member
Clocks

Sanjoy

I have done some quick research on this and come up with the following:

1. All RTC chips that I can find would require come sort of processor interface to set and read the clock information from the chip using a suitable protocol such as I2C.

2. You could use a receiver module and obtain the time from a 'local' atomic time transmitter. However a quick search this morning did not show any such transmitters in India - but there may be one, I don't know.

Edit: Just found this:
The Time and Frequency Standards Laboratory is a part of the National Physical Laboratory in New Delhi which maintains and calibrates the Indian Standard Time.

Features of the Time and Frequency Standards Lab include:

* Four caesium and rubidium atomic clocks
* HF broadcast service operating at 10 MHz under call sign ATA to synchronise the user clock within a millisecond.
* INSAT satellite-based standard time and frequency broadcast service which offers IST correct to ±10 microsecond and frequency calibration up to ±10-10.
* Time and frequency calibrations are made with the help of pico- and nano-seconds time interval, frequency counters, and phase recorders.

3. You could receive the time from either the GPS or Indian Satellite systems.

However with all these solutions wou would need a microprocessor (or a serious amount of discrete IC's) to allow you to decode the signals received.

Sorry I can't be af any more help and good news

PS. Just found some Information from the Indian National Physics Laboratory

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#### AtomSoft

##### Well-Known Member
i think you can make one with no micro by using a 555 timer. Some 4017's a ton of transistors and some 7-segs. But im not the guy to make one since its a waste of time.

You might as well buy a clock lol

if you really want to make one then buy Micros. You can spend as little as $10 to make this whole thing. But the programmer cost around$40 so your looking at $50 USD initial funding #### Mike - K8LH ##### Well-Known Member They used to make such things. I built my first 6-digit 7-segment clock in the late 70's using one of these ICs. You just added 6 transistors, 7 resistors, 6 displays, switches, a 1-Hz crystal time-base (which was a seperate little circuit board with crystal and 8-pin osc/divider IC), a speaker for the alarm, a regulated power supply, and a relay for the timer output. I wish I could remember the IC manufacturer and part number. Sorry. Mike Last edited: #### gaspode42 ##### Member Do a search for NTE2061. I'm not sure where you are but they cost about £6.50GBP #### AtomSoft ##### Well-Known Member heh thats cool !! seeing that i would use a 40 pin pic and create my own lol Seems simple enough... would even use a internal osc. But since he cant program. and it does save time and money on starting i think thats a good choice #### Nigel Goodwin ##### Super Moderator Most Helpful Member Seems simple enough... would even use a internal osc. Internal oscillator isn't accurate enough for a clock, but for a mains powered one you could use the incoming mains 50/60Hz - which normally gives very good accuracy. #### wejos ##### Member this project is interesting #### be80be ##### Well-Known Member Internal oscillator isn't accurate enough for a clock, but for a mains powered one you could use the incoming mains 50/60Hz - which normally gives very good accuracy. That's what a NTE2061 uses incoming mains 50/60Hz Capable of 50Hz or 60Hz Reference Frequency Last edited: #### Mike - K8LH ##### Well-Known Member I think it's amazing and amuzing that I built almost the same Clock/Calendar/Alarm/Timer using a little PIC as the one I built 30 years ago with that specialized discrete IC (lol)... Mike #### Attachments • Charlie Clock 1.PNG 1.3 MB · Views: 814 #### AtomSoft ##### Well-Known Member Mke! you are making me jealous, your work always look so clean and right lol That is a nice IC. Saves alot of time but only drawback is ... cant be upgraded. In my new clock (gave myself a deadline of sept 2009 will include the ability to have a calender and multiple alarms for any day. #### Mike - K8LH ##### Well-Known Member Jason (AtomSoft), That picture in my previous post is of the novelty PIC charlieplexed clock (featured in the Projects sub-Forum; K8LH Novelty Single Chip Clock) so it's reasonably upgradable. You're correct that the specialized IC could not be upgraded but it had a ton of features (6 digits, clock, calendar, alarm, appliance timer, etc.). It was an extremely expensive project too as I recall. The IC and the 7-segment displays were rather expensive. Then I had to buy the little 1-Hertz oscillator/divider circuit board and kit. Switches, Case, etc., added up to about$50 or so...

Regards, Mike

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