Back to the old days. Making a analog behaving digital clock. Purely build with TTL ic's. No microprocessor, no code. The clock face consist of 60 RGB leds.
Recently i bought a radio controlled clock module for under 20€.
Were has the challenge gone? Although i earn my money programming I still like building TLL more. It's Lego were you can build computers with.
So why not a clock. Yet another clock! boring!!
But this one is analog, not really, but it tries to simulate it.
No Digits just minute,hour and second pointers turning around the .... clock
No processor power. Just logic blocks and functions
There is one different approach to this version compared to allot of the TTL versions.
The seconds, minutes and hours actually move.
They shift around. Every pointer has a 60bit shift register, which is told to shift the pointer on every clock pulse.
The 60bit shift register is looped.
The outputs of the shift registers a fed into a RGB led.
So i don't need 180 leds i just use 60.
Every analog clock face is round so this clock will be too.
Another difference is this one is some what programmable.
You can program the shape of the pointer.
This clock needs to be loaded. When you start it you have to load the shape of the 3 pointers.
The Hour pointer can be 5 Red leds wide or dotted or...
The Minute pointer can be 3 Green leds wide
The seconds is just 1 blue led but or no leds if the moving of a blue led every freaking second is pissing you off.
Due to the sad fact that TTL isn't easy to come around these days I had to trow some designs away.
It's not even a TTL clock any more. It ttl like cmos. FFL clock would be a better name because all the chips contain fets instead of transistors.
No more CW/CCW adjusting. The clock cannot move counterclockwise. Which is a damn shame is you ask me.
I could not find, 8 bit shift left/right versions with bus-like connections.
So i had to stick with the 74**595.
For the loading part i use the 74**195 4bit parallel in-out shift register.
Which was convenient because 8bit register (595) cannot make a 60Bit loop.
I could make a loading mechanism to feed a 64 shift register and disregard the last 4bits but the idea was to make a simulation of an analog clock so i wanted it to loop and behave like a real gear.
So 6times 8bitters and 3 times 4bitters make 60bit.
An other analog behavior is the simulation of the hour pointer. An analog clock moves the hour pointer continuously. It gradually moves toward the next hour with every passing minute.
So this one does to. The hour counter is build to shift every 12 minutes.
I have thought off many extra features, programmable colors, CW/CCW, radio controlled but the layout is already complicated enough.
So i decided to skip them and implement them in a new design with cpu core which simplifies the design. Then i can load any pattern to the clock pointers at any seccond.
But first the non-cpu, analog behavior clock.
- Labs project
TTL Analog clock
March 28, 2015
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