LaserCutter: Laser Cooling Monitor

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Participants Beatskip
Skills Electronics, Reverse engineering, Microcontrollers
Status Planning
Niche Electronics
Purpose Use in other project

Short introduction

The K40 LaserCutter has been set-up to use an Aquastream XT pump in a PC watercooling system. The goal of this project is to make a quick safety board that will monitor the water flow, read the water temperature and controls the fans. It will disable the laser if the safe parameters are not set.

Initially these "safe operating conditions" are:

  • The water should be flowing
  • The water temperature should not exceed 70 Degrees celsius
  • the fans should be running

on if these parameters are met, the laser will enabled internally. This board will act separately from the main controller board and should prevent any damage to the laser system itself due to user error.

Status Log

Here is a short list of the tasks that have to be performed and which have been done already:

  • unchecked box (t.b.d) First prototype (with the laser)
  • checked box (21-12-2022) PCB design
  • checked box (20-12-2022) first schematic design
  • checked box (18-12-2022) Base architecture diagram
  • checked box (18-12-2022) Define goals and requirements
  • checked box (18-12-2022) Project setup and Wiki skeleton


The project will have the following requirements:

  • Limit feature-creep in the design, it should be a simple, compact board that has one goal: "keep the laser safe from PEBKAK"
  • Easy to produce, open-source PCB
    • If possible be able to make it with the laser cutter itself by burning away paint on a copper-clad board.
    • large enough components so no expert soldering skills are required to assemble it, although some will be needed.
  • have a compatible Aquabus Header
  • have multiple conventional PC fan headers with PWM control and RPM sensing to attach fans and a conventional water pump to not limit this board to Aquastream XT pumps
  • Temperature Sensor connector for systems that don't use the Aquastream XT and/or have flow sensing redundancy.
  • Flow Sensor connector for systems that don't use the Aquastream XT and/or have flow sensing redundancy.
  • a tricolor or addressable LED for easy status readout
  • USB and/or UART for system integration and debugging/connectivity


The Aquastream XT waterpump has been provided by Beatskip under the simple condition that if the pump is not used anymore in the laser, or the pump breaks and beatskip is still a member. then it should be returned to him. for the rest, this pump is dedicated to the laser cutter as long as needed.

The pump itself is quite an expensive and feature packed beast, but perfect for a system like this. some main features include:

  • A usb connection for readout and control
  • PWM speed control
  • internal flow sensing
  • internal water temperature sensing
  • a propietary bus (basically I2C) called AquaBus to read all data and set all parameters and to attach more peripherals.

the specifics for this bus still have to be reverse engineered. Note: this "AquaBus" is named identical as another propietary water pump control bus by Neptune. These are not the same bus and have no affiliation. very confusing, since the Neptune aquabus actually has been reverse engineered. The Aqua-Computer bus has not. The goal is to open-source any results from this to allow fellow hackers to use these nice pumps in a non-computer envirionment.

a user manual for the aquacomputer multiswitch device shows a pinout and basic description of the aquabus.



It is currently unknown if the pump operates as master or as slave.

Main architecture

It is proposed to use a cheap RP2040 Devboard as a basis.

  • These devboards have an onboard WS2812 RGB LED for status readout.
  • it has USB and UART connectivity.
  • Dirt cheap (~5 EUR including shipping) and widely available
  • Easy programming and development
  • Simple pin headers to connect to the Main board.
  • The PIO statemachines can be used to interact with the Aquabus if simple I2C master doesn't cut it



These are the initial schematics.



Here is the inital board design. Note: this is one of my cruddiest fastest board designs ever, but it's just a fancy relay controller. didn't want to spend more than an hour on it. may revisit it in the future if i can be bothered.

You can download the Gerbers here: File:LaserSafetyBoard-V0.1.7z