This project is what I would like to think of as a successful failure. I have been working on a low resolution LED clock for the past few weeks and in the end, I regretfully overpowered my Arduino UNO - causing it to fry as well as burn out my LEDs. However, I did accomplish quite a bit and will share my process so that maybe someone can learn from my mistakes.
Step 1: Determine Size, Then Gather Tools and Materials
For this project, I originally wanted a 12" x 12" square with 144 LEDs so that one LED would light up every 10 minutes. I thought this size would be perfect - I could buy a pre-made shadow box to house my LEDs and focus on coding the LEDs. However, after playing around with low resolution images, I determined 144 LEDs would not be enough to make an image clear enough for people to recognize what it was. So, I decided to double the amount of LEDs and have one light up every 5 minutes instead. By doubling the amount of LEDs, I doubled the size of my project, which meant I needed to build a shadow box too.
- Craft wood
- Screws or wood glue and nails
- Paint, stain, or finishing material of choice
- Glass or clear acrylic cut to size
- Rice Paper window adhesive film
- Window film application solution
- Foam board
- Fully addressable RGB LED strips (I bought these)
- Arduino Uno
- RTC (Real Time Clock)
- 9volt battery clip connector (to power Arduino)
- 5volt external power supply
- 3M Command Velcro Strips
- male and female wire connectors
- Soldering Iron**
- Needle nose pliers
- Wire cutter/stripper
- Screwdriver or hammer
- E-6000 adhesive
- Ruler or other straight edge
- Exacto knife or box cutter
* Stranded wire is fine to work with, however I recommend using solid.
** You can get a kit that includes most of the tools needed here.
Step 2: Test Your LEDs, Then Lay Them Out
Since I got an AMAZING deal on my LED strips through eBay I was nervous about them not working. I ran a strand test on them first before I started to cut them to size to make sure I didn't get ripped off. The first test I ran didn't work. After a little digging, I found that my LEDs have a clock pin and the test I ran didn't define a pin for it. After defining the clock pin, I ran the test again and every LED worked!
Next, I cut my LEDs in strips of 24 and taped them on my counter to get exact measurements. The LEDs I bought are just over an inch long. I chose to use that measurement for the distance between each row to keep them evenly space out. My LEDs covered approximately 13" x 27" - which ended up being the perfect size because I had a piece of 18" x 30" glass in the garage being unused.
Step 3: Build the Frame
Because I am not an expert in carpentry, I wanted to keep the frame simple. I found craft board at Lowes and had it cut to size. Of course you can get any type of wood you want, but I wanted something durable, lightweight, and cheap and this craft board fit the bill.
There are two ways you can assemble the frame.
- Wood glue and nails
There are pros and cons for each method, but I chose to assemble the frame with screws.
** I suggest having someone help with the assembly of the frame unless you have the proper clamps to hold the pieces together **
First, I had holes pre-drilled into the wood. Doing this made the actual assembly process easier (screws go in straight and the wood wouldn't split).
Next, I aligned the side, top and bottom pieces and held them tightly together while my husband used the power drill to screw them together.
The frame came together nicely, however the screws I bought were suppose to sink into the wood a bit so that I would have been able to use wood filler to fill in the holes and have a smooth surface, but that didn't happen. Most of them were flush with the wood but two of them stuck out of the wood a tiny bit. My husband said we could take it apart and use wood glue and nails instead, but I didn't mind the head of the screws showing and I was anxious to get this thing put together! So, I left my holes unfilled and sanded the rough spots before I painted the frame black.
Step 4: Adhere Window Film to Glass, Then Add to Frame
Adhering the window film to the glass is an easy, but wet process. I recommend doing this step over a towel to soak up some of the solution.
- Measure and cut film. (I cut mine an inch or two longer than needed so that it would be easier to apply)
- Clean glass and allow to dry.
- Soak glass with application solution.
- Remove backing from film and lay on glass.
- Starting from the center and working your way out, use a squeegee to push air bubbles out and allow glass to dry again.
- Trim edges. (I recommend placing a ruler on the edge of the glass to hold film in place to get the cleanest cut possible)
Once the glass was ready and the frame was dry, I applied e6000 glue around the edge of the frame and carefully lined the glass with the edges. I placed a few heavy objects on top of the glass to hold the glass in place until the adhesive dried. This particular adhesive takes 24 hours to dry and 72 hours to completely cure.
Step 5: Create the Backboard
For the backboard I used two pieces of foam board - one to hold the LEDs, wires, etc and the other to hide most of the LEDs, wires, etc.
First, you need to take precise measurements of the inside of the frame. It is important that the backboard fits snug inside the frame so that the LEDs and other components don't get shuffled around too much. When measuring, make sure to get the depth of the foam board as well.
Once you have the measurements, use a pencil to mark the 4 sides on one piece of foam board. When I made my marks on my foam board, I made sure to have my box as close to the center of the board for two reasons:
- I need to have flaps to tuck the backboard into the frame.
- I wanted clean, straight edges and not the rigid edges found on some foam boards.
Next, measure 2" out from each side of the box that will be your top and bottom. These will be your CUT lines along with the lines you made for the sides. (I had originally wanted a flap for each side of the backboard but ultimately decided two would suffice.) CUT THE OUTSIDE BOX WITH A RULER/STRAIGHT EDGE AND A SHARP BLADE.
After cutting, you should still have two lines on your foam board. From each of these lines, measure the depth of the foam board going towards the center of the board. I forgot to allow for the depth of the board before I scored for the flaps and my backboard did not fit. I had to go buy another piece and do this step all over again. :\
Once this is done, see if your backboard fits snug inside the frame. If it does, AWESOME JOB! If it doesn't, repeat this step with your second piece of foam board.
With your second foam board, you will just cut a piece to fit inside the board with flaps.
* I chose to use black foam board for both pieces, but I highly recommend using a piece of foam board that is the same color as the LED strips so that the strips aren't clearly visible through the glass piece (unless you want them to be visible of course).
** Get your foam board from Hobby Lobby or other craft store. I had purchased one of my boards from Dollar Tree and it started falling apart almost instantly.
Step 6: Lay Out LEDs on Backboard
On the second piece of foam board, map out the LEDs strips. Once you've made your marks, peel backing from the strips and carefully apply them to the board. They cannot be easily removed.
Once all of your strips are placed, punch holes through the foam board on each end of the strips so you can run your wires along the backside. I would recommend punching the holes at least 1/2" from the ends of the strips.
Step 7: Solder LED Strips Together
For this step you will need 24 long strips of wire and 24 short strips of wire.
The ground and power (5v) do not have to be soldered in any particular way just as long as all of the LED strips are connected together. I soldered mine in a "snake" format with the short wires.
To make the coding process easier, solder the data and clock in a linear format. Starting from the end of the first LED strip, solder the long wires to the data and clock plates, feed the wires through the hole and then solder them to the beginning of the second LED strip. Continue this process until all strips are connected together.
- GND should connect to GND
- 5V should connect to 5V
- DI should connect to DO
- CI should connect to CO
Take the 3M Velcro Strips and adhere one to each corner on the backside of the board with the LEDs strips. To make sure they lined up evenly with the foam board with flaps, I attached the velcro strips together before taking the backing off and applying it to the other board. By using the velcro strips, you will still have access to the wires should you need to replace one.
* I taped the wires down that ran through the back to keep them from moving around. If you measure the lengths of your wires better than I did, you may not have to tape them.
Step 8: Connect Power Source and Test LED Strips
The arduino does not hold enough power to run itself and the LEDs so a secondary power source is needed.
I bought a cell phone charger and stripped it to use as my secondary power source. The wires inside were stranded so I soldered solid wire to the end of the ground and power wires to have a durable end to plug into the arduino and LED strips.
- 9volt battery clip connector and 9volt battery plug into the Arduino
- ground wire from LED strips connect to ground pin on Arduino
- data wire from LED strips connect to the pin on Arduino defined in coding
- clock wire from LED strips connect to the pin on Arduino defined in coding
- power wire from external power supply connects to power wire on LED strips
- ground wire from external power supply connects to secondary ground pin on Arduino
Once everything is connected, run a strand test to make sure the LEDs are wired together properly.
Step 9: To Be Continued...
This is where my project currently ends. Before I had purchased my secondary power source I had borrowed an external power supply from my instructor so I could continue working on this project over the holiday weekend. I thought I had been the last person to use it and thought it was left at the 5 volt setting and didn't bother to look at it before I ran my strand test...
Bye-bye Arduino! The power source was set to 12 volts - which is more than double than what is needed. I killed my Arduino in two seconds. With it being a holiday weekend, I couldn't get a new Arduino ordered in time. The following Monday I got another one from my instructor. I connected it to my LEDs to run a strand test but the LEDs did not turn on. I fried my LEDs too! :\
I am completely bummed out that I did this, but I've learned quite a bit from this experience. I am thankful that I hadn't gotten around to wiring up my RTC to go with it otherwise that probably would have been fried too. I do plan on continuing this project in the near future. Hopefully my next instructable will be a fully working low res LED clock!
Step 10: Things to Consider
I made a few alterations to the overall look of the housing that you may want to consider.
- After adhering the glass I decided that I did not like the solid black frame. I went to Lowes and found some flooring pieces that had great colors and textures to add to the sides. They weren't too difficult to cut and had an adhesive back which made them easy to apply. If you do something similar to this, I would suggest using additional adhesive to apply them.
- After running my first strand test with the LEDs inside the housing, I could easily see my LED strips through the glass. This probably could have been solved by using a piece of foam board the same color as the LED strips, but I applied a second piece of contact paper to the glass inside the frame. This diffused the glass a little more and the strips weren't as noticeable. This also made the LEDs look a little softer, which worked out perfectly.