I’m somewhat new to KiCad and I’m currently working on building a very bright Wi-Fi enabled lamp/mood light! This is just a fun side project, from which I hope to gain more experience with electronics and KiCad.
I wanted to start this topic to share my work and get your insights along the way.
Here are the components of this project:
High power RGBW LEDs on an Aluminum Core PCB (KiCad)
The Aluminum Core PCB will help manage heat dissipated from the LEDs
RGBW PWM Driver PCB, FR-4 Core (KiCad)
This LED driver is not integrated with the LEDs on the aluminum core PCB, since manufacturing with Aluminum Core PCBs is more expensive.
The LED driver will generate less heat, thus an Aluminum Core PCB is not necessary
A fan motor controller for active cooling. Situated in the lamp head (KiCad)
Putting a motor in a lamp is unusual, but it will result in superb cooling.
PCB with MCU and WiFi module (KiCad)
User Interface PCB (KiCad)
Some buttons or dials for the user to interact with the lamp
Power supply (20V input, ~30+ Watts)
Mechanical components
Lamp body and joints to allow orientation of the lamp head to be changed
Here is a rough sketch of the design showing the locations of the important components (this is not final):
The lamp head is going to be quite narrow and long for an aesthetic design (about 3cm in width and 30cm in length)
This also means that the fan is going be very small
The lamp head will be able to rotate on its major axis, meaning it can direct light up and around a room (functioning as a mood light) and can be directed down to serve as a regular lamp.
What is left to do, with some anticipated challenges ahead:
Active cooling
Choosing a quiet and small motor to run the fan
PCB with MCU and WiFi module
Selecting a cheap MCU
Selecting a cheap WiFi module
User Interface
Power supply (20V input, ~30+ Watts)
I’m most likely going to use an old laptop charger
Mechanical components
Thinking of 3D printing everything
I would love to hear what you think of the project, and also if you have any tips for me as I move forward on the list of things I still need to do. Also, I’m thinking of using JLCPCB’s assembly service since they have low cost components and PCB manufacturing costs - does anyone have any other suggestions?
Is this for a one-off or do you have ambitions for mass producing this?
You apparently think differently, but I would not want to have a fan in my desk lamp. Especially a small fan. Smaller fans make more noise.
One solution could be to use a bigger fan in the foot, and then guide the air trough the frame.
Have you ever considered to make your own heat pipes? They’re quite simple to make. In their simplest form you put a bit of water in a copper pipe, then heat it until the water boils and there is just water and steam in the pipe, but no air and then you solder it closed. Higher quality heat pipes have a wick inside that distributes the water.
Dissipating the heat neatly is a mayor part of LED lighting. The little experience I have suggests that efficiency of the LED’s goes down near the highest power, which results in disproportionately more heat to dissipate. Using more LED’s and running them at max 70% of their current helps keeping heat down for the same amount of light.
For just a few lights, look up COB (Chip on Board) for LED panels on Ebay/Ali/China. Lots of different sizes of Aluminimum backed panels for cheap prices.
Ditto on dissipating the heat. Sucking heat out of the LED is the major thing if you want these high-power LEDs to last longer than 30-60 days. Heat pipes are certainly the BEST option for moving the most heat per unit of time, without the noise of a fan. Copper is expensive, but easy to hammer into shape. And it is a superb conductor of electricity.
You might want to build a demo lamp using the 3W leds that come mounted on an alum plate. This will give you a much better “feel” for the temp and heat dissipation required.
I think you will be surprised by the amount of heat.
Those smd led packages are VERY difficult to solder by hand. The plastic bodies get soft quickly and will deform, ripping the internal bond wires. You better be good at soldering.
That’s right! Go with a 3 meter diameter 4 blade propeller powered by an R2800 Double Wasp!
Seriously this is my fairly recent LED lamp. It has no pcb and is a bit simpler than what you describe. It features a natural wood stick (including bark) from a tree in our yard.
@paulvdh I’m not thinking of mass producing. I hadn’t considered heat pipes, but it seems like a great idea because of their superb thermal conductivity. I did some research and it seems like I should be able to get some ready made copper heat pipes from Ebay/Ali along with some cheap RGBW LEDs as you mentioned. Although shipping does seem to take a long time (12-24+ business days!).
I also came across this cool $1000+ lamp by Dyson which claims an LED life of more than 60 years because of the excellent cooling provided by heat pipes!
Hey! Nobody has ever accused me of being artistic!
I think of Dyson as doing some first rate engineering; but I am not sure that LED aging can be so greatly improved by controlling temperature only. My “stick lamp” uses four 350 mA rated white LEDs running at only about 15 mA each. They produce a surprising amount of light like that. But it stays “on” 24/7 with the purpose of providing enough light in our laundry room so that you can easily see your way through the room with the doors closed and without turning on the 80W ceiling fluorescent fixture. I think that running the LEDs at far under their maximum rating (and also keeping temperature down) WILL probably greatly extend the lifetime.
For your MCU and WiFi module, maybe consider pre-fab modules. There are a bunch of ESP32 based boards at Adafruit that you can integrate into your design, or go with a RaspberryPi Zero W that has wifi for only $10.
3D printing for the structure parts would probably be fine (you’ll want to use one of the higher temperature resistant filaments around where the LEDs are). But, 3D printed fasteners are possible, but in my experience sketchy at best. I’d go with actual metal fasteners from your local hardware store before printing them.
Ha!
And is the company going to be around in fifty-nine years to honour their claim when the LEDs fail, or, will the purchaser still be around or remember about said claim?
Seems like a marketing ploy rather than wonderful designing.
I’ve finished most of the layout for the LED Driver Board. I am satisfied with the components I have selected, but my lack of experience with PCB design has me questioning my placement of components and traces. Please let me know if there is anything out of the ordinary.
Here is a quick overview of the LED driver board, followed by the schematic and layout:
Board uses the TPS92200 synchronous buck LED driver
Has 4 repeating buck driver sub-circuits to drive each LED color: Red, Green, Blue, White
LED Current: ~0.7A per color
LEDs used: Cree XLamp XM-L (not shown)
Will likely use 2-3 LEDs in series, thus the output voltage range is ~4 - 12V depending on LED color
Vcc = 20V
Connectors wire to LEDs on a different board which are not shown
… Heat pipe it is.
