This repository holds design files and code related to my ESP32 based LED CCT Controlled.
Light is an important part of any living situation. One factor that is often overlooked is Color Temperature, measured in Kelvin. A typical range is from 2700K-5000K, with lower numbers being redder and higher numbers being 'brighter' and bluer.
I appreciate the role that f.lux has on my computer screen color, and I have attempted to emulate similar room lighting using a Phillips Wake up Light. However, I would like to have control over the lights being on/off and their color temperature throughout the day automatically.
To accomplish this, I set out to design a system that could be incorporated in my Home Assistant Setup, so that I can easily integrate it into my location based automations and even incorporate my digital calendar (i.e. if I am working at night, I want the color temperature to mirror my schedule).
I wanted to combine an ESP32 using ESPHome (Specifically the Cool White + Warm White Light platform), combined with a white tunable ("CCT") LED strip that I can customize and place around the house.
For this project, I have been using an DOIT ESP32 DEVKIT v1 as the base.
For future iterations, I may plan to just use the ESP32 module (i.e. without the development board), e.g. ESP-WROOM-32, but this will require me to be able to solder/have on hand many SMD Resistors and capacitors.
For the first iteration, I am using the 5m Tunable White LED Strip Lights, 12V from superbrightleds.com. It is definitely a bit on the pricey side, and I plan to source cheaper parts from aliexpress.com, but I wanted to have a strip that I could rely on to work to minimize troubleshooting steps.
I chose 12V LED strips intentionally (over 5V LEDs that are available) as I want to be able to power long runs of LEDs without significant voltage drop/heat dissipation concerns. It also allows me to buy a slightly cheaper power supply (fewer amps required). The LED strip above has a rating of 13.8 Watts/meter. As I bought 5 meters of LEDs, this works out to 5.75 amps of current at max load.
I am only planning on (at least initially) using the LED strips for a maximum of 2-3 feet, for 1 amp. With that in mind, I picked up a 12V, 1 amp DC power supply.
The ESP32 runs on 3.3V, however. I could not be bothered to design an include a switching buck converter, so I opted to include a pre-made 3.3V output, up to 21V input Buck converter from adafruit that I can include with a 4 pin header.
When choosing a transister, I went with one that can switch a high current (at least 1 amp) of 12V, and quick on/off time (so I can run PWM signals from the ESP32 at at least 1kHz). Based on some quick googling, I've narrowed down to two:
- IRLB8721 (N-channel power MOSFET, TO-220). Can carry up to at least 15A without a heat sink (Rds . Purchased from Adafruit. Threshold voltage Max of 2.35V (< 3.3 V as required from ESP32). This is confirmed to work.
- FQP30N06 (N-Channel MOSFET, TO-220). Looks very similar to IRLB8721. Gate threshold voltage max of 4.0, may not work. Unconfirmed.
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