I'm building a project to flash three concentric rings of LEDs in sequence to give the effect of light moving from the centre to the edge. The circumference of each loop is based on an even number of LED blocks (three LEDs per block @50 mm), so the three strips will be:
Strip 1 610 mm 12 blocks 36 LEDs
Strip 2 1400 mm 28 blocks 84 LEDs
Strip 3 2050 mm 41 blocks 123 LEDs
What I figured out so far is that I can use an Arduino Nano to control the pattern, and a MOSFET to turn each strip on and off with the right timings.
I came unstuck looking at power and voltage specifications for the MOSFET, then saw diagrams using other components in the circuit and am completely out of my depth. How can I do this?
I'm planning on using white SMD5630 LED strips (60 LEDs/m) and have calculated the power/current for the largest strip (2050 mm, 41×3 LEDs) based on power information for this LED from How to select an appropriate transformer for 12 V LED strips as being 41 A/492 W, but maybe a grownup should check this.
I'm assuming I'll need three identical circuits, one for each strip.
Best Answer
Per the specifications of the SMD3528: You apply 12 V to the strip. Each sub-group has three LEDs and a resistor.
The power calculation is given as: Total power = (0.08 W x LED_Quantity).
Or use 0.4 w x LED_Quantity for type SMD5630.
Using the total number of LEDs (LED_Quantity) calculate the total power, then divide by 12. This gives you required current (A).
So you will need a power supply with an output of 12 V at (A) ampere.
If you plan on flashing these strips with an Arduino output a good method would be to use a MOSFET in the DC line powering the LEDs. The MOSFET would need to be rated for at least 10 A. In place of a discrete MOSFET a similar rated solid-state DC relay module could be used. Solid-state relay modules often have opto-coupler inputs which are ideal for driving with an Arduino. If using a module be sure it is a DC type, not an AC type.