Thread: Robot RGB LEDs
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Unread 12-05-2016, 11:17
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Re: Robot RGB LEDs

We did RGB LEDs last year and had some fun with them as indicators on our lift and to indicate our alliance color on the drive train.
https://www.youtube.com/watch?v=vmCKHJGC6jU

The LEDs were driven by an Arduino Leonardo that was powered off of USB plugged into the roborio and communicated over I2C. The Arduino sketch was written with the help of FastLED and elapsedMillis for non-blocking delay.

To break it down, you're interested in:
* length of strip and number of LEDs
Gives you a sense of pixel density. We used 5m, 300 LEDs.

* #### LED
This number indicates the size of the LED. For instance, a 5050 is 5.0mm x 5.0mm. A 3528 is 3.5mm x 2.8mm. The larger the area of the LED, the larger the power draw and the more light it can put out.

* addressable vs non-addressable
Addressable means you can control the colors of the lights independently. Non-addressable means you can only set one color for the whole strip. Strips sometimes indicate a code such as WS2811, WS2812 or LDP8806. This indicates the type of microcontroller used, so it's usually a good indication that the lights are individually addressable. Just make sure you know what you're getting.

* waterproof/sealed vs bare
Waterproof or sealed typically means the strip comes in a form-fitting silicone sleeve. The sleeve can be removed but getting the strip in and out can be a real pain unless you slit the sleeve. The sleeve does act as a nice diffuser but if it's silicone, it can provide it's own challenges to installing securely. I don't recommend allowing the strip to move when the robot is in motion. It puts a lot of strain on the LED connections which can break easily. Resoldering those connections can become quite the chore if you choose to keep it in the silicone sleeve.

* cut lines
If you plan to cut the strip, make sure that it says it has cut-lines/solderpads between lights. Most do. It's important to check how many lights are between cuts since this can vary. Some will cut between every light but some cut every X lights or every N inches.

Edit:
Forgot the whole reason for posting...

We used Newstyle LEDs bought from Amazon:
http://www.amazon.com/NEWSTYLE-Progr.../dp/B00MHUK83K

They were ok but they were prone to breakage, requiring frequent re-soldering. This may have been in part due to the way they were used. The ones on the lift were tacked on by the silicon with no individual support for each light. Gravity and motion may have been main culprits for our frequent need to re-solder. The strips mounted horizontally on the drive train never required any repair.

The mentor who obtained them for us removed them from the silicon, soldered, and replaced the casing before giving them to us, so I couldn't tell you how they were upon delivery.

Last edited by jweston : 12-05-2016 at 15:14.
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