As a little kid, I remember the Glow in the Dark stars and shapes one could stick on their ceiling for night time view, frankly I remember the shapes being extremely boring
Older, equipped with some basic electronics knowledge and a deep interest in innovative display systems, I thought of a way of transforming my Rooms wall into a dynamic glow in the dark canvas.
While doodling on a Vinyl Glow in the Dark paper with a bright white light, i realized an interesting display could be built from it: GLO.
GLO consists of an array of 5mm UV LEDs that run on a simple linear axis, powered by long thread and a Stepper motor. The UV leds act like pixels, turning on at the right time, and drawing our desired text on UV sensitive surface such as my Wall (paper).
The result is a cool mystic, message board that glows in the dark and displays Twitter Trends, RSS Feeds, and Custom Text on my wall…slowly fading out.
Warning: Lying in bed watching favorite news slowly fade out, can make you (me atleast) very sleepy.
Here is a Video of it, pulling and printing a Sports Headline from BBC on my wall:
This is also a contest entry, if you like it please vote for it :)
Step 1: Building the UV LED Array
I am building this as per my resources and what I think is the most efficient way to implement this. When you are building be sure to let the Inventor in you come out, do stuff the way it suits you. Nevertheless this is how I implemented mine
So in this step we will be focusing on building the UV Led Array that will act as our Drawing Pen.
Parts you need for this step:
1 x 2” by 3” Perfboard
12 x 5mm UV Leds
12 x 220ohm Resistors
2 x 74HC595 Shift Registers
2 x IC Mount/Holder
1 x Some hookup wire
1x 7 wire Ribbon Cable (the length should be a a little longer than your display length)
Tools you need:
Start by placing everything on the perfboard, and think about how you are going to solder everything in place, it’s a small perfboard, so everything will be quite snug. You might find it easier to use Helping Hands to hold everything while you solder.
The leds have to be positioned at the centre of the board while the other components at either side of these.
Before you start soldering everything, just place all the components in their places to make sure everything will fit well and will conveniently connect together when needed.
Here is the important bit, the leds will only leave a sharp impression on the UV sensitive surface if they are right up against it. Currently, as it stands, the Shift registers in their Sockets protrude out, however we want the leds to protrude just a few millimeters above the IC’s
Keeping that in mind, let’s begin soldering, I recommended removing everything from the perfboard and soldering the component in this order.
Place the IC sockets in their place, and solder them. Next place the resistors, and ONLY solder their common leads. Next bend the resistor leads and solder to achieve a common ground connection between each resistor. Snip the excess.
Next place the leds in place, ONE BY ONE, it is important that you get their orientation (Short lead -, Long lead +) and height right. They should protrude about 2-3mm from the ICs. Now solder each LEDs negative, (short lead) to its respective resistor.
Repeat this for each LED, carefully making sure they are all level with each other.
Now follow the schematic and make all the required connections, because the board is quite small you will have to come up with innovative ways to make the connections (messy). The Terminal Block in the diagram is a representation of the Ribbon Cable.
Solder your ribbon cable at one end of the perfboard, and connect all the wires that will be connected to the arduino to it.
The order of the connections on the ribbon cable are not important as long as you remember (label them!) which one is which. For me, the order was dictated by which connection was the easiest to form.
I ended up with:
Master Clear, Ground, 5v, Clock, Data, Output Enable, Latch
Yours may differ.
Once everything is soldered, you need to divide the 12 LEDs, into a group of 6 LEDs, this will form 2 lines of text. Gently push the leds apart until you have 6 at either side with a little gap in between.
If you are getting confused about any step, do check out all the photos, i have attached loads of them.
Once that is done, give yourself a pat on the back and lets move on to testing.