LED Stair Lighting Hack with Raspberry Pi


Source: http://blog.hekkers.net/tag/staircase/


This interesting project shows how to light stair with Arduino and Raspberry while someone is climbing.


Robert Hekkers did a amazing work described via several steps on his blog:


Step 1: The dimmer plug

“OK, but how do I control 12 LED strips independently? And not just on/off, but also in brightness. I didn’t like the idea of using 4 RGB LED controllers, so I started searching for a >12 channel LED controller. After some days I finally got the inspiration I needed – a JeeLabs Dimmer Plug! The Dimmer Plug uses a PCA9635 IC to drive and dim up to 16 LEDs independently.. that should do it! The Dimmer Plug uses I2C to communicate with the outside world, so that shouldn’t be a problem either.”


Step 2: Raspberry Pi and i2c

“The things I want to do with the LED strips involves sending certain ‘patterns’ to the LED driver at specific intervals. Will the Raspberry be able to do this in a reliable way? I don’t know yet, cause right now the Raspberry which I’m using to test this LED driver, has (almost) nothing else to do than run a single Node app that uses this LED driver. But what if more drivers are running, all consuming CPU cycles, or what if the OS feels it’s time to do something else for a change, just when the LED strips need to be adjusted in brightness? We’ll see.. maybe not now, but too much delay or other irregularities should be visible right away, so I decided to just wait and see how this turns out in practice.”


Step 3: Kit Velleman mk120 to detect people on stair

“after my NAS was fixed, I could continue working on some components I need for our staircase renovation. One of those components is the Velleman MK120 Infrared Light Barrier.


But I needed some proof of how well (or not) these light barriers would work, so I did some tests with the soldered kit on my desk. Well, with about 70 cm. between the transmitter and receiver, even moving a forefinger (or cat paws..) through the beam triggered the buzzer. I also did some test to let the IR beams bounce on nearby objects and that did have an effect on detecting objects, but I hope I can minimize that effect.”


Step 4: Progress and changes

“A small update. As you can see the stairs are almost done. The banisters still need to be painted and some minor ‘errors‘ need to be resolved, but the major part of the things I’m not good at are done!”


Step 5: The end is in sight

“The sketch for the Arduino Ethernet is also progressing nicely – MQTT is operational, i2c is working fine too  and I haven’t seen any glitches which I did see when the Raspberry Pi was controlling the LED driver. So all that’s left to do is connecting the light barriers as inputs to the Arduino so that the sketch knows when someone’s walking up or down the stairs.”


Step6: Finished

“This post should have been made 6 weeks ago or so, but I just couldn’t find the time with all the other things I wanted (and some which I just had) to do. But this week  I realized that delaying this post any longer would probably mean it would never be made, so I sat down, read my last post about this project to see where I had ended.”



Full story here: http://blog.hekkers.net/tag/staircase/

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