# An interesting LED "display"

#### Raymond Genovese

Joined Mar 5, 2016
1,658
About 15 years or so ago, I bought a battery-operated toy "robotic" dog as a gift for someone. As I remembered, it was a pretty simple toy, but, at the time was novel. It would make noises and had an LED display for eyes. You could "communicate" with the toy by pressing a button on it's head and by making noises (I think a newer version had a "bone" with a magnet in it that you could holding near the "mouth" and the toy would respond. It also had minimal walking ability and ear-flapping. It could also go to sleep.

The idea was that you had to keep communicating with the dog to make/keep it "happy" and, when it was happy, its eyes would light up with hearts and it would play a song and a whole bunch of junk.

Recently, the recipient told me that it no longer worked but it was really liked and they wondered if it could be fixed. I took a look and [quietly] groaned that the screws had been striped and a few pieces disassembled (obviously someone had already attempted a fix). So, I said I would see what I could do. Long story a little shorter...I found a new one for ~$20 with shipping as a replacement and that left the old one to be brutally salvaged....by me. The LED "display" seemed pretty cool to me and this is why... Here is the display as hearts. and the "sad" eyes display and either the right or left "eye" could also appear like this: There are only four LEDs and these are not LED strings. Instead, they are normal LEDs (maybe high intensity at the time). Four layers of "lens'" were used. What is cool (to me) is that each "lens" is pattern drilled...here is the hearts "lens"... and a close up of some drilled "jewels" The key is that the LEDs are mounted so that they are at different levels - Top and bottom and two middle levels for the left and right "half lens" Pretty cool. Has anyone ever made something like this in any of their projects? I may replace the LEDs with bi-color ones and slap a couple of touch switches in a box with this display...add a controller and some power and program a "Love Detector". Two people each put a finger on a touch pad and some sounds are played while flashing the LEDs for the different "symbols". Finally (after a few seconds) the display ends with two hearts for a love match or two others for a mismatch. Of course I would need a third, hidden, switch so it could be rigged #### KJ6EAD Joined Apr 30, 2011 1,570 It's an application of frustrated total internal reflection most commonly used for signage. I've played with it a bit to create a multicolor map of sorts with each layer a different color. #### dendad Joined Feb 20, 2016 3,251 RGB LEDs would be better than bi-colour ones. That is an interesting tear down. #### RichardO Joined May 4, 2013 2,271 Pretty cool. Has anyone ever made something like this in any of their projects? Yes, I have made numeric displays by Laser etching clear acrylic sheets and then edge lighting them. A google search for " edge lit numeric display " Yields lots of amazing pictures similar to this: Oddly, I don't seem to remember having pictures of my own. I will have to remedy that and post them here. #### Reloadron Joined Jan 15, 2015 4,850 Some pretty cool stuff. The edge lit numeric display reminds me of the early Nixie Tubes but on a larger scale. Something else which I like is high voltage discharges through acrylic blocks, some of which can be seen here. After the block is etched using high voltage it would be neat to edge light it using different colors. Thanks Ray for the thread and RichardO for the contribution. Ron #### RichardO Joined May 4, 2013 2,271 Something else which I like is high voltage discharges through acrylic blocks, some of which can be seen here. After the block is etched using high voltage it would be neat to edge light it using different colors. Great idea. I wonder if the same "lightning" pattern would show up when edge lit. It would make for a great effect in a model railroad layout. #### Reloadron Joined Jan 15, 2015 4,850 Great idea. I wonder if the same "lightning" pattern would show up when edge lit. It would make for a great effect in a model railroad layout. I really don't know but I have thought about it. I was given an Eagle made from Acrylic, I have a thing about eagles. Anyway I started looking at ways to edge light it using some RGB LED strips and changing the edge colors using PWM on the different colors. Stuff like fade in and fade out. Problem was my eagle really wasn't designed around edge lighting. Then I remembered that old Arcs & Sparks web page with the acrylic blocks zapped by high voltage. I figured with the right LED strip around the border it may make for interesting. Just never persued it. Ron #### KJ6EAD Joined Apr 30, 2011 1,570 I installed one of those color changing LEDs into a counterbore in the bottom of a small translucent cherub/angel figurine once. The result was a fairly even overall glow once the outer surface was sanded to a matte finish. Most ordinary discrete LEDs have too wide a dispersion angle to couple well into thin plastic or glass sheet material so much light is lost to high incident angle, but you can find ones with narrow ≈10° included angle if you look. #### atferrari Joined Jan 6, 2004 3,623 About 15 years or so ago, I bought a battery-operated toy "robotic" dog as a gift for someone. As I remembered, it was a pretty simple toy, but, at the time was novel. It would make noises and had an LED display for eyes. You could "communicate" with the toy by pressing a button on it's head and by making noises (I think a newer version had a "bone" with a magnet in it that you could holding near the "mouth" and the toy would respond. It also had minimal walking ability and ear-flapping. It could also go to sleep. The idea was that you had to keep communicating with the dog to make/keep it "happy" and, when it was happy, its eyes would light up with hearts and it would play a song and a whole bunch of junk. Recently, the recipient told me that it no longer worked but it was really liked and they wondered if it could be fixed. I took a look and [quietly] groaned that the screws had been striped and a few pieces disassembled (obviously someone had already attempted a fix). So, I said I would see what I could do. Long story a little shorter...I found a new one for ~$20 with shipping as a replacement and that left the old one to be brutally salvaged....by me. The LED "display" seemed pretty cool to me and this is why...

Here is the display as hearts.
View attachment 158989

View attachment 158990

and either the right or left "eye" could also appear like this:
View attachment 158991

There are only four LEDs and these are not LED strings. Instead, they are normal LEDs (maybe high intensity at the time). Four layers of "lens'" were used.
View attachment 158992

What is cool (to me) is that each "lens" is pattern drilled...here is the hearts "lens"...
View attachment 158995
and a close up of some drilled "jewels"
View attachment 158996

The key is that the LEDs are mounted so that they are at different levels - Top and bottom and two middle levels for the left and right "half lens"
View attachment 158997
View attachment 158998

Pretty cool. Has anyone ever made something like this in any of their projects?

I may replace the LEDs with bi-color ones and slap a couple of touch switches in a box with this display...add a controller and some power and program a "Love Detector". Two people each put a finger on a touch pad and some sounds are played while flashing the LEDs for the different "symbols". Finally (after a few seconds) the display ends with two hearts for a love match or two others for a mismatch. Of course I would need a third, hidden, switch so it could be rigged
One of the first things I built.

The closest I ever did was a luminous display with my daughter's name initials. Dark red acrylic with a recess for every LED forming the letters. Being seen through the plate made them look not so agressively bright.

They went ON in sequence as the alarm clock played the melody.

Took me some time to realize the conceptual error in the design: to appreciate such an incredible effect, the daughter of such an inteligent father should have been awake before the alarm started!!

IIRC, LM3915 at work.

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#### RichardO

Joined May 4, 2013
2,271
As promised, here are pictures of the edge-lit display I made.

#### Raymond Genovese

Joined Mar 5, 2016
1,658
Good stuff! Thanks all.

@Reloadron I was familiar with that site - those guys are wild! I knew about them for their magnetically shrunken coins.

Here are a couple of ref articles on the DIY issue for edge illuminated signs that I thought were particularly informative:

https://makezine.com/projects/edge-lit-led-signs/
https://makezine.com/2010/06/21/how-to-edge-lit-display/

Off-the-shelf product with some potential https://www.amazon.com/RGB-LED-Glass-Edge-Lighting/dp/B00K742YZ8

...and a nixie tube project (sort of like @RichardO pics) https://makezine.com/2012/02/18/edge-lit-led-nixie-tube-display/

Joined Jan 15, 2015
4,850
Good stuff! Thanks all.

@Reloadron I was familiar with that site - those guys are wild! I knew about them for their magnetically shrunken coins.

Here are a couple of ref articles on the DIY issue for edge illuminated signs that I thought were particularly informative:

https://makezine.com/projects/edge-lit-led-signs/
https://makezine.com/2010/06/21/how-to-edge-lit-display/

Off-the-shelf product with some potential https://www.amazon.com/RGB-LED-Glass-Edge-Lighting/dp/B00K742YZ8

...and a nixie tube project (sort of like @RichardO pics) https://makezine.com/2012/02/18/edge-lit-led-nixie-tube-display/
Thanks for sharing the links. As the sweet dog days of summer fade I will have a need for some winter projects. I have a string of the mentioned 50/50 RGB LEDs, a few micro-controllers and pretty much all the electronics so a matter of getting some acrylic to try and etch.

Ron

#### PhilTilson

Joined Nov 29, 2009
78
Same subject, different tack! I recently purchased some solar-powered lights to put on poles as parking aids. They were slim tubes, around a foot long and an inch in diameter, the top five inches of which was an acrylic tube containing a string of large 'bubbles', around ¼ inch in diameter. At the bottom was a single white LED which illuminated when the ambient light fell below a certain level.

What impressed me is that a set of four of these 'tubes' was powered by a single 1000mAh AA rechargeable cell, the 1.2V increased through a small boost circuit, and because the 'bubbles' catch the light from the LED, they seem to be remarkably bright. The fact that these four lights can run for 12 hours or more on one tiny AA cell, and give out really useful light is, to me, quite remarkable. I would attach a picture but I am currently abroad, and they are at home!

#### Raymond Genovese

Joined Mar 5, 2016
1,658
I may replace the LEDs with bi-color ones and slap a couple of touch switches in a box with this display...add a controller and some power and program a "Love Detector". Two people each put a finger on a touch pad and some sounds are played while flashing the LEDs for the different "symbols". Finally (after a few seconds) the display ends with two hearts for a love match or two others for a mismatch. Of course I would need a third, hidden, switch so it could be rigged
I actually ended up bread boarding that (I surprise myself at the silly things I will do for S & G).

I love me not.

I love me.

There is little chance of this making it to an enclosure as I am already sick of it and, surprisingly, beta testing has been distinctly disappointing for convincing women that they *must* love me because "science" says so.