Revision as of 22:55, 22 August 2012

After having recently bought in a RGB LED Strip into the hackerspace, I received a lot of positive feedback about it. 2 people even gave me 20 CHF each to buy more LED Strips so that they can be used around the hackerspace. In particular, around the perimeter of the room next to the ceiling, where there is a little ledge. Eventually, they could be added under tables, on shelves, and so on to improve lighting within the HS. Here are 2 videos and a pic I took of how they look like:

• 

  LED Strip above the solder station

• 

  Video of the strip from afar

• 

  Video of the strip from up close

I have also uploaded a video on youtube where you can see me looking at them up close. Please note the many solder points, indicating that the factory that made these strips either used a poor manufacturing process, or simply took rejected strips, chopped them up into the pieces that worked, and soldered them together to sell at a lower price.

What are LED Strips?

Here is an exhaustive explanation and tutorial from laydyada. In essence, there are 3 SMD (Surface Mount Technology) RGB (Red Green Blue) LEDs (Light Emitting Diodes) on a segment with 3 resistors which allow the ~3 v LEDs to be drivven using a 12v power supply. These 'segments' are continuously joined together to form spools 5 meters each. Sometimes you can buy them in smaller bits (1 meter, 50 cm, 1 foot, etc), but sticking to a 5 meter spool is the best.

Where to buy?

The dilema I have is that for around ~60$ I can cover the perimeter of the hs with basic 5050 LED RGB Strips from eBay, like the ones that I bought in, however there are several other, attractive options available:

eBay

The precise LED Strips that I bought can be found here. I am not too happy with the quality, so I may get a refund, or a partial refund in the near future. My biggest concern is that there are way too many solder points leading me to believe that these strips are of crap quality, and won't last the specified 50'000 hours.

You must understand that there are several types of LED Strips. If you want RGB LEDs, you can either choose 3528, 5050 and 5060 SMD package sizes. The most common one is 5050, and I highly recommend you stick to that. The next variable is LEDs/meter. The ones currently at the hs are thirty LEDs/meter, however I sugest that we buy the six-ty LEDs/meter kind, so that there is double the brightness.

There are also various degrees of waterproof-ness available. The basic kind (epoxy) is very bad, does not last long, and starts to yellow very quickly. Especially if it is poorly made. For this, you have to pay approx 5$ extra for the strip on ebay, where as in reality it is nowhere near as expensive. The next kind of coating is epoxy+silicone sleeve. This is better, but still has epoxy. The most expensive kind (although the material price difference is minimal) is silicone coated in a silicone sleeve. This can withstand the toughest conditions, and still look new years from now.

Specialized sites

If the website is based anywhere else other than China, don't even bother. The markup is ridiculous (heck, even eBay's markup is pretty big!). If it is in China, avoid, unless the price is very good, meaning that it is either a super-low quality thing, or a fake. Either way, avoid.

TaoBao

Prices are very similar to eBay. Not worth the risk, added shipping cost, and time in my opinion unless buying a lot.

Manufacturers

Great for bigger orders, however on smaller ones, the shipping can be prohibitive (most insist on using DHL, adding a ton of shipping fees + unwanted taxes). The prices are really good though. Like 1.45$ a meter good.

Plan of Action

Here are the steps which need to be taken in order to upgrade the lighting at the HS:

1. Decide on type of LED Strip
   1. Get the brighter (60 LEDs/meter) or the cheaper (30 LEDs/meter) strip?
   2. Get the cheaper but lower quality one or the better quality but more expensive one?
2. Buy 20 meters of LED Strip and wait a couple of weeks for it to get here
3. Create an Arduino sketch with networking capabilities to control the strips
4. ???
5. Profit!!!

Uses

• Control remotly using a script (netcat)
  • Web server running on an Arduino board to control the LEDs: http://62.220.135.201/rgb
  • Little scripts for the current implementation:
    • File:Led.sh
    • File:Led-strombo.sh
    • File:Led-colors.sh
    • File:Led-prog.sh
    • File:Led-all.sh
• Controled by the music (color, intensity)
• Special program: Burger time, etc

Suggestions

This time

Iteration 1

I would recommend to get these 5050 RGB 60 LEDs/meter Strips instead of the cheaper ones (like the ones that I've got), seeing as the seller has very good feedback, with no real issues concerning his LED Strip selling - I'm sure it's better to pay 15 CHF extra to get double the brightness and good quality strips. If you don't want to waste an extra 8CHF, you can get these, but have a look at the guy's reputation. If you guys insist on staying with the original plan, we can get these ones then.

We will also need a 400w power supply (or multiple smaller ones), some serious mosfets, optocouplers (do we?), an Arduino, network interface, a [user:gcmalloc], and a bunch of various bits 'n pieces. For the power supply I suggest we get 2 185-200w constant current ones (this is a must if we want to control the strips easily), or something along the lines. I'm sure we'll find something. Plus, we probably won't be using all the power at once, unless we're outputting white at max power (that would be equivalent to the power output of a 60w incandescent lightbulb every meter), so I guess a power supply of about 350w total will do.

Currently, I have 60 CHF out of the 75 CHF required to get the good LED Strips. We will also need to find a constant current power supply.

Iteration 2

Got a better idea? Please share, I'm eager to hear other people's opinions!

Next time

Put LEDs under the tables, instead of the lightbulbs, and even on the shelves!

Project Leader

• Sasha

Participants

• Rorist
• gcmalloc
• Francois
• Freestorm