IC Transistors - can someone help me out?

[modernjack3]

Hello guys !

 

First of all , sorry for this kinda not computer focused post but i really need some help ...

 

I am currently working on a LED based clock, but i want to build it oldschool so no adruino, raspberry pi oder other "advanced" devices, just a quartz crystall signal tht will be transformed into a 1Hz signal,

some (probably about 18 of them ) Shift registers (8-Bit) of the type "74HC595" and the LEDs...

But here comes my problem - the shift register has by far not enough power to supply an LED so what I need are transistors - there comes my next problem - which ones should I use for tht job ? I will be using about 140 LEDs to show the time so Id prefer some kind of IC tht is packed with ~10+ Transistors for this use.

 

If it matters how tht clock will work, ill post it in another post right here .

 

So already a BIG "thanks" to all the ppl tht are willing to help me out !

 

(I am not a native speaker so please excuse my mistakes)

 

J.

[multifrag]

http://www.eevblog.com

Probably will be better place to ask. Sorry for not being able to help

[Aleksbgbg]

Hello guys !

 

First of all , sorry for this kinda not computer focused post but i really need some help ...

 

I am currently working on a LED based clock, but i want to build it oldschool so no adruino, raspberry pi oder other "advanced" devices, just a quartz crystall signal tht will be transformed into a 1Hz signal,

some (probably about 18 of them ) Shift registers (8-Bit) of the type "74HC595" and the LEDs...

But here comes my problem - the shift register has by far not enough power to supply an LED so what I need are transistors - there comes my next problem - which ones should I use for tht job ? I will be using about 140 LEDs to show the time so Id prefer some kind of IC tht is packed with ~10+ Transistors for this use.

 

If it matters how tht clock will work, ill post it in another post right here .

 

So already a BIG "thanks" to all the ppl tht are willing to help me out !

 

(I am not a native speaker so please excuse my mistakes)

 

J.

 

As far as I only understood IC and Transistors out of this post, I would suggest using a trial version of Circuit Wizard to build a circuit for what you want as a 'plan'. I am sure you will understand the options they give you, and I have built many circuits before using ICs. Good luck!

[MAC_VTi]

Looking at the datasheets for the sn74hc595, there should be enough current per pin, as most LED's only take about 20mA. To play it safe, you could use the MM74HC595, as it allows for 35mA to be drawn per pin, and still comes in a DIP package, so should be easy to work with. I've a datasheet linked below if ya want to take a look. Also, make sure to put current limiting resistors on the LED's to make sure they don't exceed the max current per pin of the IC. 

 

https://www.fairchildsemi.com/datasheets/MM/MM74HC595.pdf

 

I'm curious as to how you plan on converting the quartz crystal into a digital display (ie your glue logic and how you plan to set the time). Also i think you should use a higher frequency crystal and a 555 timer, as it would allow you to fine adjust the clock for accuracy.

 

MAC_VTi

[modernjack3]

Hey MAC_VTi!

 

Well I planned on using a 555 - the shit register is mainly there to control the LEDs.

 

My Clock will consist of 3 rings - one inner Ring made out of 60 Blue LEDs whcih i want to turn on one by one every second so the circle fills- when the circle is full , the minute circle ( in red and around the second circle ) will have one LED more turned on and the inner circle will reset... when the red circle is full , a green circle will (consisting of 12x4 LEDs) have one added and everything resets....

 

thts the plan ... gimme a second to make a nice paint picture

[modernjack3]

Here is how ill add them up:

[MAC_VTi]

Looking at your diagram, if you wire your 60th second output to the master reset (SCLK on the MM74HC595) on the second ring, and to the clock on the minute ring, it should do want you want. Just note that the reset is an active low, so you're gonna need a NOT gate to invert your output. Basically do the same thing again for the minute ring with the hour ring, and wire the 24th hour output pin to the master reset for the hour ring, and you should be good to go. I can draw a diagram if you need one.

MAC_VTi

[modernjack3]

Yep thats my plan ^^

[MAC_VTi]

Yeah, you should be fine. How do you plan to power it? Batteries/ Power supply?

MAC_VTi

[modernjack3]

Oh and because you asked - ill make a switch tht will cut the 1Hz system off from the  first Shift register and then adding in 3 buttons one to send a signal to the second part , one for the minuite , and one for the hr

[MAC_VTi]

Be sure to post some pics when done. Should be interesting to see.

MAC_VTi

[modernjack3]

Well you might want to subscribe to this thread now because i will satrt maybe next week and it will also take some time so .. i might be done in 2 or 3 weeks

[Stefan1024]

Hello guys !

 

First of all , sorry for this kinda not computer focused post but i really need some help ...

 

I am currently working on a LED based clock, but i want to build it oldschool so no adruino, raspberry pi oder other "advanced" devices, just a quartz crystall signal tht will be transformed into a 1Hz signal,

some (probably about 18 of them ) Shift registers (8-Bit) of the type "74HC595" and the LEDs...

But here comes my problem - the shift register has by far not enough power to supply an LED so what I need are transistors - there comes my next problem - which ones should I use for tht job ? I will be using about 140 LEDs to show the time so Id prefer some kind of IC tht is packed with ~10+ Transistors for this use.

 

If it matters how tht clock will work, ill post it in another post right here .

 

So already a BIG "thanks" to all the ppl tht are willing to help me out !

 

(I am not a native speaker so please excuse my mistakes)

 

J.

 

I assume you are looking for something like the ULN2003A:

http://www.ti.com/lit/ds/symlink/uln2003a.pdf

 

It only has 7 drivers, but it only has 16 pinns so it's alread pretty dense.