aarontc / rgb-daylight

ARCHIVED; now at https://gitlab.idleengineers.com/aaron/rgb-daylight -- An RGB LED controller for simulating the full day light cycle run on an RPI

RGB Daylight Simulator

RGB LED controller for simulating the full day light cycle run on an RPI

I wanted to create an artificial source of "daylight" for the purpose of subconsciously being aware of what time it is as I toil away at my computer all day. So I picked up an RGB LED strip to stick behind my computer monitors and threw together this project to achieve that.

It works by calculating the position of the sun throughout the day and changing the color and intensity of the RGB lights to try and mimic the light you would see coming from behind a curtain over a window.

It is intended to be run on a Raspberry Pi as an inexpensive controller. The concept is simple enough to run something simpler like an Arduino but I just felt like doing it on a Pi and it was easy to use existing python modules for the sun position calculations. This also leaves the door open for potential future features to add remote control if you use a WiFi equipped model.

Install

The program doesn't install and is just used directly with ./rgb-daylight.py. It has the following dependancies

• astral: sudo pip3 install astral
• pi-blaster: Clone git repo and standard autoconf install

You may need to manually run pi-blaster after installing it the first time or just reboot

Once everything is installed you can just download these files and run them:

Build

You're going to need to build a driver interface of some kind to connect the RPI to the LEDs. If you are using a typical "5050" +12V,G,R,B LED strip like I designed this with you can take a look at this example schematic on what parts to use and how to connect them. The pins that are used on the RPI aren't significant, any GPIO will work. You just need to update the pinout in rgb-daylight.py to match how you put it together.

Setup

After the first time you run rgb-daylight.py a settings.json file will be created with several things in it that you will need to change to match your build, location, and preferences.

led_pins

These are the GPIO pin numbers that the LEDs are controlled with. The default values match the schematic but if you made changes you will need to update those to match your build. The allowed pins are limited by pi-blaster so you should look at the documentation for that for info on which ones you can use.

intensity

This is the overall brightness of the lights as controlled by the PWM. It takes decimal values between 0 and 1 (exa, 0.75).

white_balance

RGB lights are rarely "white" when all three elements are on fully on. This will allow you to adjust individual intensities for the RGB channels to attempt to correct this.

position

The position settings are perphaps the most important for this project because they are used to match the light to your local(or any other) specific daylight conditions. They are used by astral to do the sun position calculations.

timezone

This needs to be set to the timezone you need to match. The possible values for this are determined by the pytz module. The easiest way to find the acceptable values is to run python3 in a console and run the following commands to have pytz print out the options:

from pytz import all_timezones
for timezone in all_timezones:
	print(timezone)

(You may need to press enter one more time after the print command before it runs)

A small note about daylight savings time. I am not 100% sure how this will handle DST. I am in Arizona where we do not participate in DST and have not needed to counter-program it. I suspect that it will "Just Work" because I think astral internally only uses UTC and only calculates relative values. So the actual local time doesn't matter. But if there is an problem feel free to open an issue and I'll attempt to fix it.

latitude & longitude

This is the exact location you want to calculate the sun position from. I would recommend looking up the location of a nearby airport and using the values for that. It will provide a known refrence you can compare your results to.

timezone_offset

You don't need to change this. This only effects the printed valus in the terminal for debugging purposes. You can set this to whatever your hours offset from UTC is.

colors

These are the colors used for the different times of the day. The default colors are intended to be more realistically subtle but you can change them to anything. The values are like the others, a decimal number from 0-1. The values are for the Red, Green, and Blue LEDs in that order for each period.

So as an example, if you want a neon magenta sunset, just change the sunset values to [1,0,0.5] and start the program.