Hackaday Clock A Day Entry: CMOS Logic Clock

Discovered I need to buffer the LED blinkers with a non-inverting hex buffer. Searched everywhere on the Internet for a CD4050E, found one on Ebay and was charged an unbelievable £3.99 for *one* chip. I ordered it and sent the guy a rude message :D

It took a while (several hours actually), but I finally got the 1Hz signal generator working on the breadboard. There was only one minor error in the schematic (see links) which I have corrected. I still don't have a oscilloscope to test the signal frequency, but the LED appears to blink in time with a digital clock that I have so I am fairly confident. I guess I will have to wait for the clock to be fully assembled and then see how well it keeps time.

I have built the 1Hz clock signal generator on breadboards, but I suspect that the value of the resistor used isn't accurate enough. I am using a 470K resistor instead of a 330K resistor. I have ordered some 330K resistors from Ebay and I will resume work in a five days, or so. It took me hours to discover this problem. *sheesh*

Okay. I know I said earlier that I was going to abandon the project, but I have reviewed the schematics and have decided that I have put too much work into their production to abandon the project. I need to build all modules on breadboards and fully test them to verify the schematic. This may take some time. I will test the 1 Hertz Clock first. Stay with me guys if you are following: I will get a PCB out at some point in the near future.

 I built a small test circuit for the CD4026 decade counters and 7 segment LEDs and connected it up to Ben Eater's clock, which I built a while ago. All good, everything worked.

Next up: build the 1Hz crystal oscillator test circuit. After that, the counter logic reset circuitry needs to be tested and then I will be ready to move to PCB.

I have ordered a bunch of resistors from Ali Express and am waiting for them to be delivered. Some components are coming from Ebay and I will be able to build a few test circuits on breadboard to verify the schematic. I am reasonably happy with the schematic, but of course I have no idea if it works until I build the test circuits.