An option for making a decorative panel with LED backlighting, which will be controlled by an Arduino, is proposed. This panel will depict the constellation Ursa Major and the constellations surrounding it. LEDs will play the role of stars. To give the picture more mystery and charm, the stars will twinkle in random order.
It is necessary
- - Arduino;
- - a computer;
- - LEDs;
- - resistors with a nominal value of 190..240 Ohm according to the number of LEDs;
- - connecting wires;
- - plywood;
- - burner;
- - soldering iron.
Instructions
Step 1
The first step is to prepare the plywood of the desired size and carefully sand it with sandpaper.
After that, apply with a simple pencil on the plywood the image that you want to see on your panel. You can use carbon paper, you can divide the surface into cells and draw an image by hand over the cells. Or, if you are good at drawing, draw by hand.
Next, we burn out the desired picture with a burner. I think this does not require explanation.
Step 2
Now you need to determine in which places you will have the LEDs, and drill holes in these places for the diameter of the LEDs. For example, in this panel, the LEDs will be in the places of the brightest stars in the picture.
On the back of the panel, determine the place where the Arduino Nano or Mini board will be located, and cut a recess for it.
Also, wires from the LEDs will need to be connected to the Arduino board. It is also advisable to hide them in recesses. Accordingly, you need to outline and cut groove tracks for the wires.
Step 3
We put the wires in the cut-out grooves. They can be fastened using metal brackets. Leave the ends of the wires free.
Step 4
Let's connect the LEDs. Remember that each LED must have a 180 to 240 ohm current limiting resistor. Therefore, first we solder a resistor to one of the legs of each LED.
Then insert the LEDs into the drilled holes. Place both legs and the resistor along the cut-out indentations.
The LED leads will be fixed in the grooves and will be in close contact with each other. Therefore, they must be insulated from each other with a dielectric. It is advisable to have pieces of heat shrink tubing and put them on the ends of the wires before soldering to the LED leads. If there is no tube, then pieces of cambric or other insulator will do.
After that, we solder the LED legs to the wires and also fix them with metal brackets.
Step 5
Place the Arduino board in its place in the prepared groove.
We solder the wires from the LEDs. It is convenient to solder the positive leads (anodes) of the LEDs to the digital or analog outputs of the Arduino, and bring the ground separately to some bus and solder all the wires from the cathodes of the LEDs to this bus.
Step 6
Now that the entire electronic part is assembled, we will decorate the panel with a beautiful frame from a picture or photograph. You can fix the frame with tin corners.
Step 7
It remains to write a sketch and upload it to the Arduino. A variant of the sketch is shown in the image.
LEDs connected to digital pins without PWM function (we looked at pulse width modulation in one of the previous articles) will light up at a constant brightness. And others, connected to the PWM pins, will periodically change their brightness. Moreover, the delay time and the pin number will be set randomly in a given limited range. This will simulate the twinkling of stars.
Step 8
Load the sketch into the memory of Arduino. The panel is ready!
From the phone charger via a mini-USB cable, we supply power to the Arduino … and admire the result of our labors!
