What kind of clock device should I use for Christmas lights?

[Gauge]

Newbie Question

My father would like me to build a circuit for him to power some Christmas lights and have them turn on/off in a particular sequence. I think I understand the basics of the counting logic I need and how to acheive that with gates and relays, but in my Computer Architecture class they always had us design circuits with the assumption that there would be some sort of a clock device that would initiate each step of the procedure with a clock tick. What device is used for this outside of the computer world, what is it called, what should I expect to pay for it, and where should I look?

Thanks in advance for any help. :wink:


-Gauge

 

[FoxyRick]

Re: Newbie Question

There are a few cheap ways to do this. For your project, you don't need anything precise, just a basic, adjustable square-wave clock. I suggest a 555 timer ic running in astable mode. Take a look at this page. It's a bit "teachy" but about 1/3 way down is an adjustable astable 555 circuit, followed by examples of connecting it to counters.

**broken link removed**

555 timer chips are as common as sand and cost pennies. They are available in various version, "555" being the generic type (NE555V). They all function similarly but check the datasheet if you use anything other than the basic 555. Any electronics supplier will supply 555's. It's hard to recommend a specific place without knowing where you are.

This is another useful site, check out the 555 circuits and square wave oscillators:

**broken link removed**

There is a site here with a few examples of LED sequencers - might be helpful:

https://www.qsl.net/yo5ofh/hobby circuits/led_circuits.htm

For switching the lights, assunimg mains power, you should look at using triacs - they are quieter than relays and will last longer.

Cheers,
FoxyRick.

 

[cages]

Re: Newbie Question

Try the 555 timer to generate the clock pulse.
they should be cheap and easy to find.
here is alink to a tutorial about the timmer but you dont need to read it all,
since all you need is a simple clock pulse .**broken link removed**

 

[Cluricaun]

Re: Newbie Question

Hi

Just some links, do not know if there are anything usefull. You have some time before christmas so I guess you manage to finish it.

.web-ee.com/Electronic-projects/projects/xmas/index.shtml
hxxp://
hxp://www.commlinx.com.au/schematics.htm Search for Christmas

I think there have been one similar thing in epemag.com, search their index. You can also try elektor there been some projects , like flashing christmas star (99/12)

So I do not know what kind of sequence you are after and what voltage but check the links and feel free to give further info I think others will help you more.

Good luck.
/Cl

 

[woody28]

Re: Newbie Question

Hi
My suggestion
Learn one of Micros Family like PIC, AVR or MCS51 be easy for ever.
I think AVR is one of best because there are varity of basic compiler like
BASCOM and FASTAVR so easy to learn even easier than discrete logic

 

[Munib]

Re: Newbie Question

u have to implement a simple finite state machine which can be easily done using very low cost atmel's 20c51 mcu

 

[djalli]

Newbie Question

Is 555 more expensive than Atmel or PIC? Forget about the work to program these chips.

Use 555. Its worthwile and cheap a lot.

 

[lokeyh]

Re: Newbie Question

You can also use a crystal oscillator.

 

[picotube]

Re: Newbie Question

You can also use a crystal oscillator.

Sorry that I'm little bit slow and could not get your point. How would a 'crystal oscillator' help in this case? If I'm not mistaken, the output frequency of this kind of oscillator is usually very high. So, it might not be possible to 'see the on/off' of the lights. Or, do you mean we need kind of frequency division circurt to 'step down' the frequency to an acceptable level?

 

[lokeyh]

Re: Newbie Question

What I meant was that you can use a microcontroller chip clocked by a crystal oscillator and do your programming in the chip to do all the controlling that you want.

 

[nimesh.joshi]

Newbie Question

No doubt IC 555 is the most cheap solution to the current problem. If we go for the option microcontroller then better and reliable and reusable easily managable option will be 8085 Microprocessor although this can be given 8086 and later.
But still 555 is the easiest solutionin astable mode.

 

[lokeyh]

Re: Newbie Question

I agree with nimesh.joshi. The timer 555 solution is simpler but the microcontroller will allow you to change your "particular sequence" easier as you only need to program it.

 

[Naveed Alam]

Re: Newbie Question

1. 555 timer
2. any simple flip-flop

:idea: or buy simple circuit for this..(and say ur father that u did it)

 

[syed intisar haider]

Newbie Question

well said NAVEED ALAM !!!!!!

this project is as simple as a b c

just use a 555 timer it is very easy to use

or else use a 8051 this will allow what aver u want as it is flexible in all respect

use simple programming that hi and low the relating pin periodically

regards