24H 7-segment binary clock

[spitfire]

Hello again.
The 10K resistor worked a treat Mike.
I have completed my circuit and have built it all on veroboard but now I have one problem which I completely overlooked before.

I have attached my diagram and the problem lies in the areas circled in red.
My problem is that I was going to use the terminal count output from U3 to trigger U4 which works but I didnt realise that pin 7 on U3 was going to be LOW for a minute wich is how long the number 9 on the previous IC is being held for. I was thinking of putting an inverter on Q3 of U3 to trigger the clock enable input from U4 on the negative edge but I dont think that will work because the inverter will only invert the logic state hence producing the same problem as before...am I rite? basicly I need to get an active low signal to trigger CE on U4 once only for a second and not be held for the entire minute The same need to be resolved for U5...can someone give me some hints on how to overcome this? By the way please ignore the switches on the diagram as I have connected them differently.
I will post pictures when this has been fixed...I made a custom 4 number 7segment display from 58 blue LED's and Im eager to see what you all think of it.
Thanks

 

[xxxxxxxxxxxxxx]

Have a look here: **broken link removed** its near the bottom of the page, and be sure to read the one on connecting them with a shortened count (just below).

I didnt realise that pin 7 on U3 was going to be LOW for a minute wich is how long the number 9 on the previous IC is being held for.

This is solved by the NOT gate in the link i gave you.

Try this, and see what happens.

basicly I need to get an active low signal to trigger CE on U4 once only for a second and not be held for the entire minute

Why? so long as there is a pulse, it should work. The clock output of the chip SHOULD be active low, and high everytime else. The input for the chip is the same, so they should work. Once again, see and try the link attached.

BTW, Have you built it yet, or is it still in proof-of-concept kind of thing?
If i'm missing something, please tell me more.

 

[spitfire]

Yeh, I had it built and tried the inverter method and it worked but only after re-cutting tracks and removing tiny solder splashes that took me a few hours to find...but it's finaly finished and its working!

let me know what you think.

I've been trying out different materials as a screen/filter for the leds because they have a terrible viewing angle. I'm going to try some frosted glass when I get a hold of some.

 

[Hero999]

You could use frosted LEDs?

Failing that, try roughing them up with some fine emery cloth, do this on one spare LED first so you can be sure you're satisfied with the results.

 

[spitfire]

I had thought of that but I like the idea of a filter screen, the glazed glass I have fitted at the moment is acutally giving a nice glow and softens the intensity of the LEDs quite abit and looks good in both dark and well lit rooms.
I used some silicone to glue the glass to the edge of the veroboard flush infront of the LEDs.

 

[blueroomelectronics]

Spitfire that's a nice piece of work.

Yours to michael11298, what's the CDS cell for? a dimmer?

 

[xxxxxxxxxxxxxx]

Thats a nice piece of work, spitfire. As hero999 suggests, I would file the LEDs somewhat flat (or close to) so they diffuse nicely.

Bill> the CDS cell is part of a dimmer system (I call it Dim-o-Matic .. sorry..lol) that changes the display brightness in different light conditions. It is two-state only (that is bright and dim) and includes a capacitor to avoid nasty display flickering when the light levels near the threshold.