Asked — Edited

Connecting Leds To The Ez-B V4

Hi, I am just taking my first steps with my ez-b v4.

I would like to connect some LEDs to the ez-b v4. Maybe some colorful ones that light permanently and an LED that can switch colors? (RGB-LED?)

Which LEDs would be good for this little project?

I already have a package with LEDs and resistors, but I am not sure if I can use them for this: Microtivity IL188 5mm Assorted Clear LED w/ Resistors (8 Colors, Pack of 80) There are also 200 ohm resistors included.

Which cable and which plug/connector should I buy to solder them with the LEDs so I can connect them well with the ez-b v4?

Do I need anything else?

I would be very happy if you could help me with my first steps.


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You won't need the resistors, the EZ-B digital ports have them built in. You wil just connnect the LED to the signal (outside) and ground (inside) pins. Don't connect to the middle (power) pin as it is unregulated and will birn out the led.

I always mix up which pin, cathode or anode, goes to which pin on the EZ-B. If you have enough spares, just experiment, or look up whichever is +, that is the one that goes to signal.

To control, you can use a Digital object for simple on/off or a PWM object for brightness control. (or the equivalent script commands)



@sucipher Be careful with attaching those leds to the signal pins.... Be aware the signal pin can only deliver 10ma.... If your leds pull more than that you could damage the port.....


Looked it up. The anode (longer lead) goes to signal.

I also didn't answer your question about connection. Pick up a bundle of servo extension cables. You can buy them from EZ-Robot but the shipping cost is excessive. If you have a good hobby shop or a MicroCenter in your area you can get them for a few bucks. eBay is also a good source. Cut off the jack side and solder the LEDs to the wire connected to the plug side.



I agree with @Richard R about the ma draw, but I have never seen LED's in those kinds of assortment packs that were more than a few milliamps. I have some 5MM Bright white LED's from (the former) RadioShack and they are only 2ma. The only ones I have seen that might be a problem for an EZ-B are the bright blue ones.

I have some Laser emitting diodes, and they need both more amps and more voltage than an EZ-B can provide, so I wired them with a TIP 120 transistor and a voltage regulator to get the specs I needed. That is also an option if you have high draw LEDs.

I am not sure how the multi-color LEDs work. I believe they have two anodes, and the color changes depending on which anode is getting power or if both are, so you would need to use two digital ports, and with those, do be careful of the amperage that you don't exceed the digital pin capacity.



Hi Alan,

The way I remember is "short" is "minus", "long" is plus".. I have a simple mind so this helps me... LOL.....

Ron R



The way I remember is "short" is "minus", "long" is plus"

Very useful. That will save me from several blown LEDs or from looking it up every time I go to install one. My big white LED that I use as a flashlight on Roli came in a bag with a nice labeled diagram, but I have a bag of assorted colored LEDs that came with no information (no voltage or amp specs or anything, so they are trial and error).



Thanks for the usefull answers so far:) If I have the ez-b v4 in front of me, where exactly are the pins I can use to provide the power to the LEDs?

I would like to solder a cable and a plug to the LEDs so I can connect them in a flexible way to the ez-b v4.

Which cables and plugs are best for this? I would be glad about some links to products at ebay/amazon/aliexpress.

I probably will have to connect them in line or parallel. Do I need some resistors for that? Can you recommend a good set of resistors?


Start here.... much of what you are asking will be answered... EZB4 Tutorial There are many more tutorials as well that will help you with what you want to do...


Please read post #2 again carefully. Most questions are answered there. servo cables can easily be found on Amazon a hobby shop or ebay. Just do a Google search or a search on the website of one of those places.


In the product review people write, that the LEDS pull around 20ma, depending on the color.

Can I use the LEDs safely with the ez-b v4, when I add a resistor between the ez-b and the LED?

Depending on the color one LED needs between 1.9 and 3.2V. The LED pulls around 20ma, as people write in the reviews. So a resistor with 220-270 ohm should do the job, since the ez-b provides 7,4 V, shouldnt it?