This is a simple Chrismas tree project inspired by bluqesh. I've updated its design adding slots for board to board connection and addressable RGB leds.
At that point I've also switched the MCU to an ESP8266 to add WiFi capability, and using the amazing WLED project to control everything.
Details
12 Addressale RGB led
ESP8266-12 as base MCU
IR Receiver (this seems to be broken)
Touch button to change color
USBC with synk capability 5V@500mA (5.1K Rd resistors)
Components
2×
10uF 0603
Chip capacitors
4×
4.7uF 0603
Chip capacitors
2×
100nF 0603
Chip capacitors
1×
30pF 0603
Discrete Semiconductors / Diodes and Rectifiers
The base dimension is perfect, but is a bit light, the tree itself must be glued to the base to keep it loked.
The bad news is about an issues on PCB. For some still unknow reason the IR circuit seems to be broken.
I've asketd a friend to land me a RGB remote to test the feature, but it seems to be not working. Now I'm not sure if it is an error on the circuit itself or if it is an issue with software.
While placing the 0603 components is not that hard if you have SMD skills soldering the LEDs is quite difficult! Mostly due to the VIAs to give the pads more rigidity. I'm still experimenting a way to easily solder the LEDs, probably using a stencil and low temp solder with hot air is the best solution.
Right now I'm soldering the second tree.
For now my assembly procedure (without hot plate soldering and solder paste) is:
Solder all the 0603 excpet the one near the USB C contacts.
Solder the USB C
Solder the 5.1K resistor skipped on step 1.
Solder the ICs.
Solder the LEDs, make sure that they are firmly soldered.
Solder the ESP module.
Check for shorts and program the ESP. Test if first 6 leds are working.
Snap the boards and solder them together
Check again for shorts and enjoy!
Probably with hot air and a low melting point solder paste step 1-6 can be done in a single jump.
Right now I only have flux, and 60/40 solder.
I managed to find a old solder paste, and yes, it makes the assemply a lot easier.
I don't have a stencil and in anyu case soldering the LEDs would require manual reworks due to vias under the pads.
To solder the LEDS with this metod i proceed as:
Fill the LED pads with the solder paste proceed with the reflow WITHOUT the LEDs.
The solder would be wiked into the vias, apply again the solder paster and properly reflow the LEDs.
With my cheap hot air station I use 360°C to solder all the components and 220°C for the LEDs.
I'm a noob with LED soldering I've melted 8 of them on assempling 4 tree. So be careful.
(Four on the first board, one fell on the fold and was lost. One had RED color not working. The others 2 has been melted on second and third board)
2
Programming
The touch button is connected to the BOOT0 pin, so you have to press that while you start the sketch upload process.
A FTDI 3.3V module with RESET is required, I didnt had one so I temporary connected a wire to ground while also pressing the TOUCH button.
The FW can be found under the WLED repository, I'm using a ESP12, so d1_mini is the right platform to choose.