LED indicator lights

[Delphine]

Our team wants to learn how to make LED indicator lights. Meaning that after the robot completes a certain task, the light would turn a specific color. Does anyone know what type of light we should use and then how we would wire it up? Any information would be a big help. Thanks

[sparkytwd]

How big of a light do you want? The easiest thing to do is use digital pins with an RGB led, that'll give you 7 distinct colors. For easiest hookup, you'll want a common cathode LED, and you'll need ballast resistors.

For something brighter, you can go with a 3W rgb LED, and a constant current source. I favor this for my projects these days: https://www.sparkfun.com/products/11850 You should be able to use 3 PWM channels from the RoboRIO to drive that.

You'll want a diffuser of some type. I personally recommend white vinyl or "blank" figures: https://goo.gl/photos/5e298N1xNBeHXxFh6

[GeeTwo]

We decided to use LEDs on the robot to communicate info back to the driver at one point this year. We had already installed some common anode 12V RGB strips that we controlled with a pair of spike relays. Especially if you're using java and the roboRIO, this post may help you out.

[Beaker]

We use 2 Adafruit NeoPixel light strips connected to an Arduino Mega to signal robot state and other values during the match. (We finally got them on for TRI, and it works great!)

- You have to solder a PWM cable or some type of wire to the end of the strip without wires because the other wires are actually on the opposite side of signal input. I use a scrap PWM cable that has a single male end so that I can plug it into the Arduino later.

- We connect the 12V side of one of those old radio voltage converters to the PDP and connect the 5V side to the light strip's Vin and Ground wires, which were soldered earlier. You could probably do this with a new VRM, but I'm just used to the older model.

- Connect the light strip's signal to a pin on the Arduino.

- The Arduino Mega reads values from the RoboRIO's DIO ports and our navX's Analog Outputs.

- For the programming side of things, make sure to install the Neopixel Library and the Arduino IDE. For more information on that stuff, you should look at the NeoPixel UberGuide and Arduino's website.

Also, we have a page of code releases here. Our light code from last year is in the LabVIEW code release. It uses I2C, but converting to analog/digital reading shouldn't be too difficult.


I know that this requires a lot of work, but it looks really cool when you get it working. I hope this helps!

[sandunashan]

I'm speaking about the battery, hard drive usage, wireless on/off and power on/off LED status lights on my laptop. It is an Acer Aspire 5755g but most laptops have LED indicators. I was also wondering if they could be used to light bright/dim when playing music.

[GeeTwo]

Originally Posted by sandunashan

I'm speaking about the battery, hard drive usage, wireless on/off and power on/off LED status lights on my laptop. It is an Acer Aspire 5755g but most laptops have LED indicators. I was also wondering if they could be used to light bright/dim when playing music.

Usually, indicator LEDs on consumer devices are controlled in firmware, or even hardware, and would not be available to the operating system. You would probably have to reprogram your laptop's boot ROM. Unless you're extremely thorough, once you did this you might never be able to trust any of your indicator lights again. Personally, I'd sooner drill a hole in my case and add additional LEDs that are controlled through a USB port. Even easier would be to build a USB dongle that fits inside a port.

[erbay]

You could use a three pin two color LED. If your team created the program for the robot, and still have additional output pins for your programmable IC chip, you could just control the two color LED with it and change the light color when the program runs its full cycle or when the task is complete. Now depending on your programmable IC you could also use the RGB LED. Your output pin should then control the current going to the LED to change colors.

Regards,
C. Erbay
http://blog.7pcb.com

[nlknauss]

The students on my team created this legacy document on LEDs for future students. Feel free to check it out. I think they've also posted code to the Github.

http://stormroboticsnj.org/resources/software/

[tickspe15]

We started using outputs on the PCM for indicator led control this year. It was much easier, lighter, and cheaper than spikes or arduinos that we have used in the past.

[evanperryg]

We didn't do it on our competition bot this year (weight problems) but we were going to use three DIOs on the rRIO MXP port to act as a 3-bit binary input to an arduino. From there, the Arduino drove a pair of WS2801 RGBLED strips, like those AndyMark used to sell.