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Help with a clock project please

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bigal_scorpio

Active Member
Seasons greetings to all,

I have just rediscovered in my bits box a clock IC from long ago, brand new in its box!

It is an RS 307-115 LED clock IC and as I need a clock to fill a hole in the car I thought I'd build one.

The datasheet for the IC states one of its uses as "automobile clocks" so I figured it would be straightforward building, but then I hit a snag! The schematic shows the IC having an input from 50/60hZ from the mains. How do I get that in the car? Especially as accurate as the mains frequency is?

Any help appreciated. BTW I have attached the datasheet as its an old RS chip that was probably made before some of you were born! ;)

Al

PS if anyone has a better or easier idea for a car clock (4 or 6 digit) then by all means suggest it.
 

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  • RS 307-115 or mm5387.pdf
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MikeMl

Well-Known Member
Most Helpful Member
I would go to an auto junkyard and buy one to fit my car.
 

bigal_scorpio

Active Member
I would go to an auto junkyard and buy one to fit my car.

Hi Mike,

Wish I could but the hole I have is not designed for a clock and I will have to make it to fit! the hole is about 110mm wide and 20mm high so I was planning on some 7 segments and a few control switches to fill it and look like it was oem.

Al
 

MikeMl

Well-Known Member
Most Helpful Member
Look at a night stand alarm clock. Some have a transformer which more or less makes ~12Vdc (or less). Bypass the existing transformer power supply circuit from cleaned-up 12Vdc from the car's system. Then all you need is a source of 50/60Hz, which can be a suitable crystal/resonator and a CMOS oscillator/divider chip...
 

bigal_scorpio

Active Member
I just had another idea for the clock

Hi guys,

I just realised that I could use the output of the car computer I have installed for the clock maybe?

I was thinking could I somehow use the ethernet port of the PC to send out a clock signal and have a kind of dumb terminal to read the data and turn it into an LED display. Is this possible or has my mind finally snapped? hehehe

Al

EDIT. I have just been googling and found many ethernet clocks but they all seem to be more concerned about using power over ethernet PoE rather than just getting the time over the cable! doh!
 
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