TTL/CMOS Linear LED Clock

Done! Working! Happy with that. I only made a few silly mistakes while soldering it up - I don't think I had to change the design or anything.

Happy with how it works!

The LEDs don't line up seamlessly, but that's OK, it actually makes it easier to read by making every 10 minutes slightly different.

Underside looks OK. I could have been better with making the connections neater.

There can be a bit of contact bounce when setting the time (especially when releasing the switch) but that's OK.

I think I'm going to mount it on the wall of my cubicle at work.

Here's my "PCB" layout. I like to use prototyping board and point to point wiring, with a layout done in vector format using Inkscape.

 This then gets "flipped" to have a copper side view.

I always end up making a few  changes on the fly.

Tested out the time setting function. The arduino is providing two frequencies, one per second and five per second. Both go into the 4066. The control pin for the one per second pulse is connected to a "voltage divider" with a switch on the low side. In the normal state, the button is not pushed, so the control pin for the one per second pulse is high, and the 4066 passes through the one per second pulse. The same control signal is also fed to the 74HC00 NAND. The other pin on the same NAND gate is connected to 5V. So in the normal state with no button push, the output of the NAND gate is low. This is connected to the control pin of the five per second pulse of the 4066. Because it's low, the 4066 gate blocks that signal.

When the button is pushed, the control pin of the one per second is now low, and the control pin for the five per second is high. The 4066 then lets through the five per second signal. 

The 4066 outputs for the one and five per second are connected together, and to an LED that therefore flashes at one per second normally, and five per second when the button is pushed. I'll use this set up to allow the minutes to be set. Pushing the button will interrupt the normal one per minute pulse, and allow though a faster pulse rate. I'm not sure what speed is appropriate - either one per second or two per second seem like good candidates.

I made up the minutes display section on a breadboard to make sure my plan would work. I used two '164s, two LED bar graph segments, and the '00 NAND gate. This is enough to prove the counting, daisychaining and resetting. I used my super old school arduino to provide power and a 1 pulse per second clock signal.

After correcting a few wiring errors it all worked! Happy with that. Although these aren't the LED segments I'll be using in the final version, it seemed like the brightness was fine using 500ohm resistors.