DIY 6 Digit VFD 24 Hour Clock , 74 series logic .

Hey


Thought I make a thread on my 6 digit VFD clock that ive started to build I did post a thread of my led version but this one will be more of the building processes as there will be a case and that too I hope .

The logic side of it is 74 series ICs with each 2 digits driven with a dual BCD counter and 2 BCD to 7 Segment drivers . AND gates are used to make the digits reset at the correct time 24 . 60 . 60

1 Second pulse ( 1 Hz ) is produced from rectified mains divided by 10 twice to keep track of the time .

there are a total of 50 level shifter sets each one consisting of 4 resistors and 1 NPN / PNP transistor pair . the level shifters are used to convert the 5 volt logic levels from the segment drivers to 30 to drive the displays .

Each segment of the VFD display sinks 100 ma of current @ 30 Volts , the supply is 35 volts , ( the 5 volt drop is over the resistor that controls segment current ) .

In the pictures I have 8 level shifters setup 7 for the segments and 1 for the grid to reduce wear on the VFD displays the 6 displays will be pulsed on and off one after the other at 200 Hz or so , so that they are not running at 100% duty cycle .

I hope to update this as I go , things I have to do are -

add the other 40 level shifters and wire up the displays , build a 35 volt , 5 volt , 3.15 volt DC supplies and make the case .


IMG_0440 by TwirlyWhirly555, on Flickr

Logic side of it .


IMG_0443 by TwirlyWhirly555, on Flickr

Level shifters .


IMG_0444 by TwirlyWhirly555, on Flickr


IMG_0445 by TwirlyWhirly555, on Flickr


IMG_0446 by TwirlyWhirly555, on Flickr

Displays and full size idea .

Looking good. Can't wait to watch you complete it.

Let me know if you ever want to sell kits as I love interesting clocks. :beer:

I love breadboards and bread-boarding....


Jerry

Clean assembly imho. Can't wait to see it working. :beer:
Will you make a video?

jcranmer said:

Looking good. Can't wait to watch you complete it.

Let me know if you ever want to sell kits as I love interesting clocks. :beer:

Click to expand...

Thanks Shouldn't be too long just need 5 more transistors . Will do

lasersbee said:

I love breadboards and bread-boarding....


Jerry

Click to expand...

Leodahsan said:

Clean assembly imho. Can't wait to see it working. :beer:
Will you make a video?

Click to expand...

Thanks , I tried to keep everything neat and in order , I will make a video going over info and showing it working .


So update - 64 transistors and 128 resistors later I have 4 displays in and running , minuits and seconds .

just 32 transistors , 64 resistors to go , I had to use a new bread-board to fit them all on as I didn't have enough holes in the power rails .


IMG_0452[1] by TwirlyWhirly555, on Flickr

next update of the full working display will be very soon

twirly

Edit -

Added the last displays , im 4 transistors short so last display isn't wired yet , but the minuits , seconds and dots are working


IMG_0460[1] by TwirlyWhirly555, on Flickr

And this is a quick video of it running , ill do a more detailed one when I get the last display wired

http://www.youtube.com/watch?v=O8EzOkK99_U .