My "special" clock - Page 1
Forum section: electronics / projects

author: modernjack3
author_rank: Contributor
timestamp: January 25, 2016, 08:59:43 pm
content: Hello Guys !So Ive been planning on building a fancy clock with a load of LEDs and a load of shift registers.Before you instantly reply with something like ~Just use an adruino or raspberry pi~ ...I want to build it this way because I enjoy building things that came from my own mind and well , I just had the idea to build a clock that way so thats how Ill go .Basic Plan:So for the time Ill be using this neat little thing right here :-http://www.hackersbench.com/Projects/1Hz/-Since this all is a "prototype" I will use multiple breadboards for mounting.Now I am looking for the right IC shift register to use.I want to pack some shift Registers together so one row adds up to about 60 Bits - ill place a flip flop at the begining that will turn on when the 60th' bit is high and turn off when the first bit is high.That way I should be getting a High that moves from the first bit to the 60'th -thus visualising the seconds.Then Ill place the "clock" input of another shift register row ( also 60 bit , yes for the mins) on the 60th bit of the "seconds shift register row".So if my thoughts are right I should now have a clock that is capable of working with seconds and mins - if I do the same fun but with only 24 bits I should also be able to work with hours .Please tell me if I have some Kind of flaw in my logic there.After this is set up I want to display the time with LEDs in a circle formation - which is why I didnt use a Binary to 7 seg coder.To drive the LEDs I am planning on using a darlington transistor IC . Any reccomendations which one might fit? LEDs should be visible in DaylightSo if everything you read so far seems fine to you - thats great - but you might ask yourself " how do I set the clock , do I have to plug it in at midnight if i want to use it?"Well for that i thought of a Little Switch that cuts off the Timing circruit from the shift Registers , and adding 3 Buttons - one for seconds one for mins and one for hours.those Switches will send a high to the clock input of the Chosen shift register row resulting in adding one up.Thanks for reading and for your help !Here are the main questions if you have forgotten them :x: which shift Arrays for breadboardx: what darlington Array for blue LEDs at daytime ( THEY WILL BE HIDDEN BEHIND SCRATCHED UP PLEXY GLASS!)x: will it work ?

author: rob77
author_rank: Super Contributor
timestamp: January 25, 2016, 09:31:34 pm
content: the idea is ok, but you have a bug by design (as long as i understood correctly)... you can't link the seconds and minutes... you have to use the output from seconds as the clock for minutes. if you would use the output from "seconds" as input to "minutes" and clock it with 1Hz you would just count 120 seconds.. not 60 minutes. (same apply for "hours" - you have to clock the hours register with the output from "minutes" )regarding the shift registers ICs 74HC(T)595 is still manufactured and also available in DIP package suitable for breadboarding.

author: modernjack3
author_rank: Contributor
timestamp: January 25, 2016, 09:42:02 pm
content: Hey rob !I think I made nothing wrong there...I said that Id use the 60th pin as clock in...And I just realised I suck at replying xD

author: MrSlack
author_rank: Frequent Contributor
timestamp: January 25, 2016, 09:43:33 pm
content: I see these projects a lot. Always good! And you're right: no uC required. You can actually build an entire clock with your 1Hz gen + 6x4026's, some diodes and 6 LED displays as well but that's too easyInstead of shift registers, you could go down a step and use a dekatron emulator (ring counter) which uses a couple of transistors per bit. You can then chain arrays of them as divide by 10/6/24 etc. A 60 bit ring would represent the seconds nicelyhttp://www.vk2zay.net/article/202Example in action:I built a one ring version on a breadboard and got bored

author: modernjack3
author_rank: Contributor
timestamp: January 25, 2016, 09:50:06 pm
content: @MrSlackWow that Looks like a LOT of work ...I am not enterly sure if I want to step down that far but it Looks really intresting.The Problem is that I still have the dream to fit my rig into a nice clock Body and not a giant , bulky one .I am also planning on making a night/ day mode that Switches with a Flipflop every 12 hrs ( day and night)how could I regulate the current with the help of that Flipflop?

author: rob77
author_rank: Super Contributor
timestamp: January 25, 2016, 09:50:48 pm
content: Quote from: modernjack3 on January 25, 2016, 09:42:02 pmsorry, apparently i missed that.

author: modernjack3
author_rank: Contributor
timestamp: January 25, 2016, 10:04:50 pm
content: So the other day i was asking myself if i could lower the current flowing with this plan (look attachments - yes it is handdrawn with a Touchscreen , in paint - dont judge)T1 would be a Transistor that is letting current pass if there is no current at ist base ( sorry I have no idea how the english term for a Transistor like that is)R1 would be an resistor defined for the one LEDT2 would be your normal Transistor that lets current flow if there is current at ist baseR2 would be an resistor defined for the 2 LEDsso if the Input 1 is high only one LED should light upif 1 and 2 are active both shouldtheir current should be in the first case like 1 led and in the second also like 1 led since they are in series right?