The Word Clock - Arduino version

Step 7 Make the word stencil and baffles

Finally, we need to make the word stencil for the front of the clock.

I used a piece of PCB material, which I etched using the pattern shown below.   I simply followed the same press-n-peel process that I used to make the controller board.  This time, I intended to use the copper layer on the side closest to the LEDs, but created the stencil the mirror image to what it needed to be - so for this one, the copper is on the outside. 

I have on order some 1/32" PCB material which I intend to use.  I will be careful to get the stencil the correct way around, (with the copper towards the LEDs), and I expect to have a bright, clear display, and I should end up with much less bleed through than I experienced with the original project, because I will make sure that the copper is on the inside of the display.. 

Prior to using the display, I cut up some more PCB stock to use as 30 mm baffles, and glued the baffles in place with hot melt glue.  If you have used 'FLAT TOP' Leds, then you won't need 30mm high baffles, you can probably get away with 10mm or so.  Just hold the stencil over the lit display and move it up and down till you are happy with the illumination, measure the height, and make the baffles that height :-)

Others who have built my previous clock have used acrylic as a display material with cut vinyl as the lettering.  That probably looks awesome!  In one case, they have used glass!

Comments

[cstack89]

 Hi I love the project, and definitely planning on making one. I'm just curious about the baffles. Do they need to be so tall? I would like to be able to hang the clock on the wall, so I was hoping to cut down on some of the thickness in the design. Would a smaller baffle work, or is there something I am missing that means they need to be the way they are? Thanks!

[drj113]

The baffles are irritating, yes!.  The reason I use them is that the lighe from the LEDs is emitted as a very bright cone.  Without the baffles, I get a beautifully  bright circle of light in the middle of the letter.  With the baffles, the diameter of the circle has increased to the diameter of the letter, and I ger even illumination.

Hmmm - I just need some sort of difuser!

[cstack89]

 Hmm so if I diffused the light using some sort of buffed plastic to diffuse the light you think I may be able to reduce the height of the inside baffles? I've heard a cheap method is adding ping pong balls over the LEDS or maybe just some kind of buffed plastic between the LED layer and the stenciled layer.

Also if the board the LED's are on and the baffles were made of some kind of reflective material or covered in aluminum tape, would the reflectivness reduce the need of an LED per letter and also help with diffusing? Similar to the idea of a backlight?

[AndyGadget]

Or you could try wide angle leds.  These will give you 60 degrees or so rather than the 10 or 20 degrees you get with the normal LEDs. 

[drj113]

I have discovered FLAT TOP LEDs on E-bay - they are really wide angle, and promise to make things even better.

Ordered.... waiting for delivery .....

[AndyGadget]

Flat top LEDs are great.  I used them in my Alien Artifact 'ible but the photos don't really do justice to the brightness.  I'm sure they'll help.

[HOMEsplice]

 I love the look of the copper on the outside. Is it possible to have it on both the inside and outside?

[drj113]

I believe so - You would just use double sided PCB stock.