This project bridges the gap between artistry and technology, transforming a wooden fountain into an animated masterpiece driven by LED patterns. Using an ESP32 running WLED firmware with a custom Usermod, the fountain synchronizes 24 mini water pumps with dynamic LED animations, turning flowing water into a living light show.

At its core is a clever hardware-software integration. Patterns designed for addressable LED strips are processed by the custom firmware, where the brightness of each virtual LED pixel (green channel) is mapped to corresponding PWM signals. These signals control the pumps via a PCA9685 module, seamlessly translating light animations into synchronized water effects.

The centerpiece of the fountain is a walnut harp, featuring “strings” made of water streams illuminated by addressable LEDs. This adds a unique artistic element to the project, blending natural wood aesthetics with modern electronics.

Key features:

• Dynamic Water Effects: LED patterns control the flow of water, creating endlessly unique animations.

• Smart Connectivity: WiFi-enabled, with control through a mobile app, browser, or integration into smart home systems.

• Custom Firmware: A Usermod for WLED that enables mapping virtual LEDs to hardware like water pumps.

This project demonstrates how a mix of creativity and engineering can turn a concept into a functional, visually stunning piece. Detailed build instructions, source code, and schematics are available for open-source enthusiasts ready to replicate or expand on the design.

Components

  1. Pine board: 200 x 30 mm and 100 x 20 mm
  2. Pine timber: 40 mm
  3. Walnut veneer, planed: 4.5 mm
  4. Walnut veneer, planed: 2.5 mm
  5. Screws: 3.5 x 65 mm
  6. Plastic bolts M8, 30 mm, and nuts
  7. Titebond 3 wood glue
  8. CA gel glue (Akrifix 705) + Activator
  9. CA liquid glue (Akrifix 702)
  10. UV epoxy resin, viscous
  11. Epoxy resin, 16-hour gelation time (fluid) 3L
  12. Epoxy resin, 1-hour gelation time (viscous) 3L
  13. Green pigment for epoxy resin
  14. Glossy acrylic spray lacquer
  15. Copper tube for AC systems, D = 9.52 mm
  16. Copper tube for AC systems, D = 6.35 mm
  17. Capillary copper tube, D = 2.5 mm
  18. PVC tube 6x9 mm (for condensation drainage)
  19. Painter’s tape
  20. Teflon plumbing tape
  21. Hot glue sticks
  22. Sandpaper
  23. “Coral” grinding disc for angle grinder

Electronic Components

  1. 1x ESP32-WROOM-32 controller
  2. 2x PCA9685 16-channel PWM controller
  3. 1x PCF8591 ADC/DAC module (optional)
  4. 1x DFPlayer mini MP3 module (optional)
  5. 1x INMP441 microphone (optional)
  6. 1x Metal speaker, 8 Ohm, 2W (optional)
  7. 24x 390 Ohm resistors
  8. 24x PC817 optocouplers
  9. 24x 0.1 µF capacitors
  10. 30x Terminal connectors
  11. 24x FR207 diodes
  12. 1x FR607 diode
  13. 24x TA6586 motor drivers
  14. 1x MOSFET module with optocoupler
  15. 2x Prototype PCB board, 90x150 mm
  16. Shielded multi-core wire
  17. Colored and hookup wires
  18. WS2812b addressable LED strip, 60 LEDs/meter
  19. 24x Mini silent submersible pumps, 5V, 120L/H
  20. 1x Brushless mini submersible pump, 12V, 4L/M
  21. 2x 40-pin male-to-female connectors
  22. 1x XL4016 DC-DC step-down module
  23. 12V gel battery
  24. 5V 3A power bank

Tools

  1. DIY laser cutter/engraver, 520x520 mm, 5.5W
  2. Disc sander
  3. Hand router with 10 mm round-over bit, 12x50 mm straight bit, and 50 mm flattening bit
  4. Hot glue gun
  5. Soldering iron
  6. ST-369 manual pipe bender, 180° (1/4”, 5/16”, 3/8”)
  7. Capillary scissors for copper tubes
  8. Copper tube cutter
  9. Gas torch
  10. Dremel tool
  11. Metal wire brush for texturing
  12. Screwdriver
  13. Angle grinder
  14. Hand saw

Sources, firmware, layouts, and schematic on GitHub.

Video tutorial on YouTube.

Detailed instruction on Instructables.


Hardware:

The final version of the electronics took me about two weeks to complete, primarily due to electromagnetic interference (EMI) caused by the mini pumps. Here are some details…

At the start, I built a small proof of concept, connecting a few mini pumps through a TA6586 motor driver directly to the ESP32 controller, and everything worked smoothly.

However, when I assembled the full setup with the PCA9685, it became very unstable (freezing every 5-30 seconds). High-speed diodes and filter capacitors for pump power helped somewhat but didn’t resolve the issue.

Next, I separated the logic power supply from the pump power supply using PC817 optocouplers. This improved stability but wasn’t perfect, as occasional freezes still occurred.

In a forum, I found that the I2C bus is highly sensitive to interference. So, I tried using shielded, grounded cables with very short lengths for power and data transmission over I2C. And just like magic, this worked! For added security, I included a ferrite core and looped the cable through it.

This setup requires two separate power sources: 5V for the logic and addressable LED strip, and 12V for the harp pump, which also powers the mini pumps through a 5V DC step-down converter.

A larger version of the circuit diagram is available on GitHub.

Instead of ordering a custom PCB, I assembled the components on a 90x150 mm prototype PCB board.

Some components are optional:

  1. The PCF8591 ADC/DAC module can be used to connect multiple potentiometers if you want to adjust fountain parameters with them.
  2. The INMP441 microphone can be used to create sound-responsive light and water effects, so the fountain could react to sounds like birdsong.
  3. The DFPlayer mini MP3 module is an option if you want to add sound effects to the fountain’s animations.

These options are also available in the firmware.

I tested the microphone with the light and water effects, and the result was very interesting—I highly recommend trying it!

Later I added 2 x 40 pin connectors on the fountain side and electronic side for ease of assembly/disassembly.


Firmware:

For the firmware, I built upon my existing work from a previous project: Wooden Reactor Simulator Nightlight Desk Lamp Sound & Light Effects.

I made minor adjustments to account for the signal inversion caused by the optocouplers in the circuit, which I compensated for in the software.

The core of the firmware is based on WLED with a custom-developed Usermod specifically for the fountain.

This offers a variety of features and functionalities:

  1. Numerous built-in effects
  2. Control via WiFi, mobile app, and web browser
  3. Smart home integration
  4. Scheduled alarms
  5. And much more.

Just imagine the possibilities! You can set the fountain to turn on and off according to a schedule, change effects based on external conditions, control it from your phone, and much more.

Unfortunately, WLED doesn’t natively support some components used in this project: the PCA9685 PWM controller, PCF8591 ADC module, and DFPlayer MP3 module. Therefore, I added support for these through my usermod.

The principle for controlling the mini pumps through WLED is straightforward. I created a reflection function that maps brightness from a “virtual” addressable LED strip to PWM, routed through the PCA9685 PWM modules. In the code, I only account for the brightness of the green color channel for each pixel in the “virtual” LED strip. So, if you want to use WLED’s default effects, select green or white colors in the palette.

The necessary WLED settings are shown in the image.

If you don’t want to configure them manually, you can download the cfg.json file and upload it in the editor:

http://your_reactor_ip/edit

For effect presets, use preset.json.

The first 24 LEDs in the virtual strip control the 24 mini pumps inside the fountain.

The 25th controls the harp’s water flute pump.

I won’t go into detail on compiling/loading the firmware here, as this is well-documented on the original WLED project site.

If you wish to compile it yourself, the source code is available in my GitHub repository.

I also uploaded a precompiled binary file to the repository.