In line of making this project as complete as possible I list in this log the components, where I got them, how much they cost and possible alternatives.

To build this project, while buying all the components, the cost comes down to $40 for the version with the prototyping cables, with the PCB and components it's about $50, this does not include the Node-RED/MQTT server.

RGB LED Matrix

I won my RGB LED matrix and technically got it for free, it was from Adafruit and is sold for $40. That was the one on all the pictures here. I bought a second matrix to build another one, this time from Aliexpress and it works just as well, but is half the price (including shipping).

The matrix comes with the power supply cable. It has screw-terminal connectors on the input and two JST-VH 4-pole female connectors on the output.

• Adafruit: $40
• Aliexpress: $20
• Mouser: €35

ESP32 WROOM devkit

If one is inclined to use the adapter PCB then only the 15-pin version is suited. Otherwise, with prototyping cables, any ESP32 breakout should be compatible, as long as 11 GPIO pins are available (careful: not all GPIO are usable on the ESP32).

• Aliexpress: $8
• eBay: $8
• Mouser: €8.50 (footprint not compatible with the adapter PCB)

Power supply

These can be bought from eBay/Aliexpress. I cannot provide a source for this one as I salvaged mine from an old appliance. As long as it can output 5V at 2A minimum it should be fine. I would avoid using a phone charger as they can often supply only up to 1A and may overheat and be unreliable. I estimate the cost of this part to about $5.

Note that you need some kind of adapter, crimps, or just plain solder to connect the power supply cable to the matrix power cable.

Prototyping cables

If you want to use prototyping cables then those can also be bought from eBay/Aliexpress for very cheap, the result might be messy, but it'll work.

• Aliexpress: $3
• eBay: $3
• Mouser: €12

Printed circuit board

You can order the PCB from a one of the many board houses, the Gerber files are in the project files section. Here are some PCB houses:

• JLCPCB: $2 for 10 boards ($0.2/board), shipping free on first order (otherwise $21 via DHL), total: $2 or $23
• SeeedStudio: $5 for 10 boards ($0.5/board), shipping $21 via DHL or $12 via Singapore Post, total: $26 or $17 (but slow and untracked shipping)
• DirtyPCBs: $17 for 10 boards ($1.7/board), $8 shipping, total: $25
• OSHPark: $15 for 3 boards ($5/board), free shipping, total: $15

PCB components

I ordered these parts from Digikey.

• 2x, 15 pin female, 1 row, female connector, 2.54mm pitch, PPPC151LFBN-RC: $2
• 1x, 16 position, 2 row, female connector, 2.54mm pitch, PPTC082LFBN-RC: $1
• 1x, 4 pin, JST-VH, male connector, 3.96mm pitch, B4PS-VH(LF)(SN): $0.4

However, Digikey has a minimum order price of about $50 before the shipping becomes free (shipping is about about $20). It might be cheaper to buy from eBay or JLCPCB sister company LCSC (I have no experience with them though).

Here are links for Mouser:

• 2x, 15 pin female, 1 row, female connector, 2.54mm pitch, 15Fx1-254mm: €2
• 1x, 16 position, 2 row, female connector, 2.54mm pitch, 803-87-016-10-001101: €1.2
• 1x, 4 pin, JST-VH, male connector, 3.96mm pitch, B4PS-VH(LF)(SN): €0.26

Frame

The frame comes with a white cardboard inside that needs to be cut to size for the LED matrix.

• IKEA RIBBA 23x23cm, article 403.784.01: $10

Corners

I rounded the cost of the four 3D printed corners to about $1. This is about 21g of PLA plastic (0.021kg * $30/1kg = $0.63) and 2h or printing time on my slow 3D printer (0.05kW * 2h * $0.2/kWh=$0.02). Of course, this part can be substituted with anything that can position the matrix inside the frame, like wood pieces or some sticky stuff.