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Many thanks to all our awesome backers for helping us get this far! We’re not even half way through the campaign and already over 50% funding πŸ™‚ We can make it, but it certainly doesn’t hurt to have a little help. We are doing our best to get the word out there, but we ask that you give us a hand: share on social media, tell your friends, tell your favorite electronics DIY blog. With a little bit of help, we can make this happen and bring the LongPixel to the world πŸ™‚

Thanks for being awesome!

As part of our process to bring theΒ LongPixel to life, we want to make sure that our manufacturer has a way to quickly, easily, and effectively test each LongPixel that rolls off the assembly line. To that end, we’ve created this test module that will interface with the manufacturer’s test fixture:

A simple button push runs through a test pattern which verifies that power, data input/output, and each color channel is functioning correctly.

The LongPixel was designed to make using analog LED strips super easy and, typically, that means RGB LEDs as they are the most common. But the beauty of the way in which the LongPixel drives these LED strips is that it really doesn’t matter what color the LEDs are. Sure, the 4 wire, 3 color RGB strips are the most convenient in most cases. But you could, for example, connect 3 single color, 2 wire, strips, of whatever color you desired. Hook up all of the strips’ power input to the V+ on the LongPixel and then each strips’ ground to a separate channel on the LongPixel and you are ready to go.

But another great use-case for choosing something other than RGB strips is if what you really need is white light above all else. Sure, you can get white light out of an RGB strip, but it’s not real white light. It’s got peaks at each of the primary wavelengths of each sub-color which looks fine to our easily tricked eyes, but is not ideal for photography or video as a lighting source. This is where the simpler white LED strips come in. But then there’s a conundrum… what color temperature do you want? Why choose?

In this demo, I’ve taken two different white LED strips, 3000K (warm white) and 6000K (cool white), and used a little math to blend the two together to maintain roughly the same total light output while fading between 3000K and 6000K. The brightness and color temperature values are stored internally as unsigned bytes (0-255) and then the following calculation is used to determine the output to send to the LongPixel:

red = ((255 - _temp) * _brightness) >> 8
blue = (_temp * _brightness) >> 8
color = (red, 0, blue)

In this case, the 3000K strip is connected to the red output and 6000K is connected to blue. The above allows fading between the two temperatures while generally maintaining the same overall brightness. For those confused by the “>> 8” code, this is just a fancy way of scaling two 8-bit values by each other. Multiply together and then right bit shift 8 places. This is much faster on a microcontroller than using larger values.

Regarding the controller, it was re-purposed from a previous project, the Fancy Pants MkII for which I built the controller as a wrist mounted device. Because of the memory demands of the controller and the pants, between having 500 pixels and a 128×64 pixel OLED display, it uses a super beefy ATMega1284p chip which is complete overkill for this project. But it certainly beat building a new board from scratch and it already came with a nice case πŸ™‚

Enough babble… check out the demo for all the juicy details and a time-lapse build.

You can find the code, PCB, and case design on GitHub

First, many thanks to all of those who have supported the LongPixel Kickstarter campaign so far! We’ve gotten a lot of great responses to the product and having passed 1/3rd of our goal we remain confident that we can obtain full funding before the end.

We wanted to also mention and clarify how the extras work this time around. We’ve partnered with BackerKit to provide the post-campaign handling of gathering our backer data and accepting orders for extra items. The options are:

  • Additional LongPixel: $12
  • 4” 3-pin jumper. $0.50
  • 5m RGB, 12V 30 LED/m: $20
  • 5m RGB, 24V 30 LED/m: $20
  • 5m RGB, 12V 60 LED/m: $25
  • 5m RGB, 24V 60 LED/m: $25
  • AllPixel: $25 *May ship separately or after the LongPixel

You can either pay for these items separately, after the campaign ends via our BackerKit page (to be sent out later) or you can add to your pledge now. Note: Adding the your pledge now helps us hit our goal, so please consider this option! To add to your pledge, go to the campaign page and click on “Manage“, then on the next page click “Change Pledge” then add the amount extra you desire (add up from the list above) and enter that amount plus your reward level amount into the “Pledge Amount” field.

Later on, on our BackerKit page, it will automatically show this extra amount as a credit that you can then apply towards any of the extras.

That’s all for now. Watch out for some awesome demo projects we’ll be showing off soon!