hello all, I'm new to this site, i was wondering if any of you guys could help me out with something, i have a 4" 4 digit 7 segment LED display that i would like to make into a clock, but im confused as to the wiring of the display it only has 17 pins on the connector, any help or ideas would be appreciated. thanks

 

Do you have a part number for the LED display?

You will probably find that your display was designed for multiplexing; there are 7 leads used for segments a, b, c, d, e, f, and g, and another one or two used for the colon. You probably have an AM/PM indicator on there as well, maybe even an "alarm on" indicator.

The other leads are either common cathodes or common anodes for each of the number displays.

 

unfortunately no there are no part numbers on it, and the way you described it, it would have to have 31 pins instead of 17, and it does have the AM/PM, and "alarm on" indicators.

 

Hello,

If the display has only 17 pins, it will be multiplexed.
To built a clock with it you have to know how it should be connected.
It is also importend to know if it is common cathode or common anode.

Greetings,
Bertus

 

It shouldn't be too difficult to work it out by systematically applying current to the pins.

 

ok, I'll try that and see if i can figure anything out
and could someone give me a quick explanation of multiplexing?

 

Hello,

Here is an example of a clock / timer with a multiplexed display.
All segments are connected together and the digits are separatly activated.
This happens so fast that you can not see that only one digit is burning.
http://ourworld.compuserve.com/homepages/Bill_Bowden/timer.htm

Greetings,
Bertus

 

ok i think i understand how it works now thanks

 

ok, i found a driver for the display(TB62709N) the clock ic (DS1307) and i have a control crystal(DS32KHZ-N) could anyone help me with a simple way to hook them all up? and if i need any other parts...

Data sheet for display driver will be an attachment

here is the data sheet for the clock ic
http://datasheets.maxim-ic.com/en/ds/DS1307.pdf