electronic dice circuit for as-level -why r teachers careles

[johnbot2002]

i am doing as-level electronics and for the coursework i am doing and electronics dice "or sumpthin or nuthin". my teacher told me about a method of slowing it down he had found in a magazine but before he could give it to me he lost it. any suggestions would be greatly recieved. also does anyone know how to take chips out of a breadboard without bending the legs and getting he legs stuck in yer fingers.

 

[johnbot2002]

the circuit is a 555 timer ic generating a 50 Hz clock going into a 4071 decade counter. and all the stuff that goes with it.

 

[Nigel Goodwin]

the circuit is a 555 timer ic generating a 50 Hz clock going into a 4071 decade counter. and all the stuff that goes with it.

To slow it down you just need to alter the timing components on the 555, for a temporary slow down (for testing etc.) simply solder a larger capacitor across the existing timing cap.

 

[spuffock]

use a chip extractor!

 

[johnbot2002]

what i mean is so that it is even harder to influence, i.e. when you press the "ON" switch it starts to flash to fast for the eye to see, then when the button is released instead of suddenly going to one number it slows down gradually through the numbers before stopping.

 

[pike]

I've seen this done somewhere...

I think he means that he wants the lights to slow down after he releases the button.

 

[johnbot2002]

yup thats exactly what i mean but i need to do it without pics,

 

[pike]

You need some kind of control circuit that slows the charging of the 555 capacitor. I would do this by using a transistor or something to eventually cut off the capacitor form charging at all.

To make this up-down transition slow, use a capacitor on the base of the transistor.

I'd show you the circuit, but i don't have anyway to host the image.

BTW: Is this magazine named silicon chip?? This is where i got my idea from.

 

[Mr_LAG]

It's possible, but it's very hard with just one 555 chip

You could try this:

Set a 555 to 10 seconds monostable. Connect the output to the reset pin (pin 4) of an oscillator (about 10 Hz). Connect pin 6 of first 555 to pin 5 of second chip through an emmiter follower (don't ask me how, i'd like to know this as well)

when first chip is triggered, output of second will oscillate very fast, and then slow down to about 10 Hz over 10 seconds before stopping

You could also use a 556 which is only one chip, and can make PCB design a bit easier.

I did an electronic dice pair for my GCSE Electronics. It was overly complicated (the guidelines suggest 3 to 5 chips, and I used 7) but I did also have a comparitor to give an indication of whice dice was higher.

One other thing, are you trying to get a realistic display (like a real dice) or just a single light? If you want the patterns to appear, try using a binary counter and then use logic to make the pattern

LAG