I'm relatively new to electronics, and as a newbie, I am seeking advice.

I'm my current project, I would like to test out the combination of RGB LED strip controlled by one ultrasonic sensor. I am starting to gather my materials and components, however I am having some trouble to determine which type of resistors I should use for the circuit. I'm not too familiar with how to find or work out the Forward Current \$I_f\$ (mA) and Forward Voltage \$V_f\$ (Volts).

I bought my LED strip package from eBay. The components included in the 5MT LED Kit were:

  • one 5050 5MT RGB LED Flex Strip Waterproof IR Controller;
  • 44 Key Remote controller; and
  • a power supply adapter.

According to the information from the seller it should be 150pcs of LED/5M.

Power Supply Specification:

  • Input Voltage: 100-240V 1.5A
  • Output Voltage: 12V DC
  • Output Current: 0 - 5A
  • Output Power: 60W
  • Safety Compliance: CCC/ FCC / CE / UL / GS
  • Working Temperature: 0°C-40°
  • Storage Temperature: -20°C-60°C

My next inquiry is: has anyone been able to find an Arduino project example combining an ultrasonic sensor with an RGB LED strip such as the one I bought?

I've found some youtube videos, however, aside from the video, there are no extra information I could use as reference.

  • \$\begingroup\$ This question would be a better fit for Arduino.stackexchange.com \$\endgroup\$
    – Passerby
    Jun 8, 2014 at 22:14
  • \$\begingroup\$ Was there any progress on this project? I am looking to do the same. \$\endgroup\$
    – user56228
    Oct 15, 2014 at 0:33

1 Answer 1


If you look closely at the LED strip, besides the LEDs, you'll see there are black surface mount resistors on the strip. So you don't need any resistors for the strip.

However you can't just power a 12V strip directly from an Arduino 5V pin. You'd need a MOSFET or power-transistor for those kinds of voltage and currents.

Here's a tutorial for the RGB LED strip.

And here's one for Reading the ultrasonic sensor.

I don't see why you need an example that precisely matches yours. Just read the distance; based on that distance calculate a color; send that color to the LED strip. It's more fun if it hasn't been done for you.

  • 1
    \$\begingroup\$ ahh... I did not realised there wre resistors in-between. Interesting... The reason I've been looking for resistors is because I have been looking at two RGB LED strip light + arduino projects: example 1) jerome-bernard.com/blog/2013/01/12/… Example 2) instructables.com/id/… Mosfet, checked. Thanks alot! \$\endgroup\$
    – user45241
    Jun 8, 2014 at 21:20
  • \$\begingroup\$ In the first link the resistors are connected between the gate of the MOSFET and the arduino. They can pretty much be any high value I think you can even leave them out, but they can provide some protection if the MOSFET fails. \$\endgroup\$
    – Gerben
    Jun 9, 2014 at 7:21

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