6 digit LED clock enclosure

Hi all

Over the past few months, ok many months I have been putting together an LED. clock circuit.To be very honest Ive not done this quite on my own as I have had much help from a good friend

The main area's of the circuit consists of:

1)A timebase section made up from a HEF4060 ,HEF4013 and a 32.768 watch crystal.

2) A PIC 16f876A the brains of the circuit

3) x2 ULN2003A LED drivers.

4) A LM35 temp sensor.

I wanted to make the digits for this clock and I purchased some bright blue LED's for the project-

x3 per segment= 21 per digit = 21x6=121 + 4 for colons = 125 LED's

For test purposes I have the clock running on some off the shelf digits purchased from ebay-
**broken link removed**

The time came to start the LED enclosure that would make up the final dial with the six digits.

Now I wanted to make this BIG!! each digit being 100x200 with six of these the dial would come out around 900mm long.

I decided to construct the dial using the Sparkfun method as it seems to work for them-
https://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=47

All went well until I decided to do a test run just to see how the Bright Blue LED's would shine through the Frosted Acrylic sheet I purchased for the front mainly to defuse and spread the light from the LED's-
**broken link removed**

I found that the LED shape was so defined and was clearly seen through the frosted acrylic sheet, even when I moved the Led back away from the acrylic each led could be seen and not the defused light that I expected.

On this forum we have had many threads about constructing the circuit for a clock but not much about the digit housing consruction.Can any give any advice and their own accounts how to overcome my problem with the LED's

Once I have finalised the project I will post this on the forum for all to see.
Lets hope it's not too long!!!!

Looking forward.

Mark

Maybe you should have gone with the LED bars used by the Sparkfun clock

If the leds are not diffused you could try sanding them a bit.

Try it on a spare. Do not ruin the entire lot without trying it. I would start with maybe 400 grit and see how it works.

3v0 said:

Maybe you should have gone with the LED bars used by the Sparkfun clock

If the leds are not diffused you could try sanding them a bit.

Try it on a spare. Do not ruin the entire lot without trying it. I would start with maybe 400 grit and see how it works.

Click to expand...

Hi 3v0 Thought that might be a solution, I have some spares so it won't hurt to try it out.

Mark

Hot melt glue is a possibility. I have not tried it though.
**broken link removed**

I once used some lengths of transparent plastic ballpoint pens, end lit by a led to make an interesting diffused lighting effect. Perhaps something like that would work for digit segments?

picasm said:

Hot melt glue is a possibility. I have not tried it though.
**broken link removed**

I once used some lengths of transparent plastic ballpoint pens, end lit by a led to make an interesting diffused lighting effect. Perhaps something like that would work for digit segments?

Click to expand...

Hi picasm

Or maybe I could use biro pen tubes cut to length as per segment but the LED light shining through the side to split the light before it gets to the Acrylic!! just a thought.

Mark

Hi all

Sorry long to get back.

I have tried some methods to my LED segment question all without success.

I tried-

1)Hot melt glue over the led.
2)Using sand paper to take the transparency off the led.
3)Used the tube from a Biro pen acting like a prism.
4)All three methods also behind defused opaque perspex sheet

All the above methods didn't make good results under test the roundness of the led was still very sharp and not defused at all.

The only other method of creating the dial I could think of was using approx 30 LED's per segment and using the LED's to define the shape but on a 6 digit clock that's 1260 LED's and thats quite costly.

Just wondering those of you that have made digital clocks and used LED's for the digits how did you make this up effectively?

To recap I was going to use the method for case construction by sparkfun once i'd overcome the defuse problem-
SparkFun Electronics

I'm using super bright Blue LED's x3 per segment to light it up.

Mark

This is what set me off with the digital clock but as you can see they used a large amout of LED's to create the segments on the digits.Of couse mine uses 6 digits.By using the method they have I wouldn't have to worry about defusing and seperating the segments and worrying about light bleeding through to other segments BUT theres a much bigger cost involveod and this is why I wanted to use only 3 or so LED's per seg and create the case like in sparkfun.

Mark

Styrene vs. perspex

Wombweller, the Sparkfun guys used styrene, not acrylic sheet/perspex, as a cover. Styrene must be more opaque than frosted acryl.