LED LIGHT STRIP BLINKING SIGN

Step One

When considering new projects like the RGB LED Strip Blinking sign it can be useful to reflect on some previous, simpler projects. Since we are trying to get an LED sign to flash alternating colors, we can use the LED Blinker.

Step Two

To further your understanding of the circuit, it is important to quickly build it using a breadboard. Try changing the values of the capacitors and resistors to see how it affects the circuit. This will help you plan for the final project.

Step Three

Looking forward to have this circuit control an RGB LED light strip, there will be some changes that have to be made. The obvious first change is that the LEDs will be replaced with the light strip. Most light strips have common anodes, meaning power enters the strip to all the colors and then completes the circuit when they leave the negative of the corresponding color cathodes. This means that the LED strip has to start at the front of the circuit at power and the cathodes will enter the anode of the capacitors and transistors. Another change  you will notice is the values of the capacitors changed. These can be changed later when you experiment with how quickly you want the cycling to happen but for now a reasonable speed to start at requires 47uF. The last change that has to be made since this will be a sign that turns on and off will be to add a simple switch.

Step Four

Most LED light strips do not come with loose wire attached. This means we will have to add some. Cut three stranded wires 4"-6" long and strip off 1/8" off each end.

Step Five

Following the directions on our soldering page, you should solder an LED Strip to a wire the same way you would a wire to the blade of a component. Tin the wire and LED Strip leads with solder.

Step Six

LED Light Strip are labeled with 12V+, R, G, B. Place the tinned wire on the tinned lead of the power source or one of the two colors you are choosing.

Step Seven

Repeat the steps from Step Six until you are finished.

*Note: You can actually get other colors than just Red, Blue, and Green. For example, if you solder a wire to both Red and Blue, the light will make Purple.*

Step Eight

Once your RGB LED Light Strip has wires on it, you can use it to prototype your circuit. It is always a good idea to prototype any circuit you plan on making into a perfboard or PCB to make sure all the components that you will solder in work. This is also a good opportunity to change the resistors and capacitors to different values to get different speeds for flashing.

Step Nine

If your circuit works and you are happy with your prototype, then it is time to turn the schematic into a PCB layout. Follow the rules on the Printed Circuit Board page when making this layout. Consider the size of your components and perfboard and your individual soldering skills when sizing the spacing of your components and paths. 

Step Ten

Following the layout of your PCB Layout, place your components in the top of your board. Be sure to place these components all the way flush to the board. This will also look very similar to how your breadboard looked. You will notice the components with jumpers are not shown here- they will be added later. 

Step Eleven

Looking at the bottom of the board, you will see your copper pad grid and the leads of the components. Bend one lead on each component 90° so that the components are secure in place while soldering them. If you skip this step, the components will slip or fall out as you flip the board upsidedown. 

Step Twelve

Solder the leads on the board. Be sure not to spill any solder outside of its copper square or connect any close leads by accident. Once you solder one lead of each component, straighten the bent ones. All soldered joints should be done with leads perpendicular to the board.

Step Thirteen

Using diagonal cutters, cut the leads off flush to the top of your soldered joint. The goal it so make the bottom of the board as close to flat as possible since this will be the side resting on the bottom of your box. This is also the step where you can add your wires and jumpers in. Since the wires are stripped so short, it is easiest to hold them in as you are soldering. If you can, try pinching them between the alligator clip on your helping hands and the perfboard- this will help keep them in place. Since the wires are already cut short, they short not need to be trimmed.

Step Fourteen

Using your PCB layout, drag your solder paths to connect the components that have to be connected and complete your circuit. Be careful not to spill any solder over to a path the is shouldn't touch. A good tip would be to use a multimeter's continuity tester to check the continuity that should and should not be there.

Step Fifteen

Your perfboard is complete- sort of... You will notice the switch is not connected to the wires soldered to the board. This is because when assembling the whole project, the switch will have to be installed into the hole first and then have the wires soldered to the blades. Follow the same steps you would when soldering a wire to the blade of a component. If you want to see your circuit work at this point, just pinch the two exposed wires together. Don't worry, this is SAFE!

Step Sixteen

Laser cut and assemble your finger joint box. Make the dimensions 3.25" x 3.25" x 1". This box needs a hole on the side for the switch you are using and a slot on the top for the RGB LED light strip to shine through. Make the opening for the switch as large as it needs to be to fit your switch. Make the slot for the acrylic the thickness of the material and a length so that it will stand up, I used .125" x 2". 

Step Seventeen

The acrylic sign can have any image engraved on it and should have a small tab that fits into the slot on the lid. The outer square is 3.25" x 3.25" and was drawn in illustrator so that it could be cut and engraved on the laser. The tab on the bottom should match the slot that you made on your box. 

Step Seventeen

Install the switch and solder on the loose wires. Since a SPST switch does not have polarity it does not matter which wire is soldered to which tab. Just make sure one of the wires is soldered to the common tab. Assembling your box and securing you perfboard, battery, and switch in place can be done with hot glue. Hot glue is great because it will keep the box together and switch in place, but if you use small amounts it will act as a temporary mount for parts like the battery that might need to be replaced when it dies. 

Step Eighteen

Carefully place the top on making sure the wires are carefully secured and out of the way as they are folded in when the lid is placed. Add your acrylic sign and turn it on using the switch. The image you engrave on the sign will glow the colors of the LEDs you chose. This looks much more dramatic in a dim or dark room.

Congrats!