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on June 30, 2011 at 3:27:30 pm


The Gasifier Control Unit v3.02

(now the Process Control Unit)


The GEK Gasifier Control Unit (GCU) is an open source sensing and control board designed to solve a broad range of instrumentation and automation needs in thermal industrial processes.  We originally developed the board for testing and control of gasification machinery.  However, it is proving equally useful for pyrolysis biochar reactors, as well as many other research and industrial control needs beyond biomass thermal conversion.  The board is a "kitchen sink" solution, including most everything one could want for thermal industrial control, all at a price point far removed from typical industrial and scientific instrumentation options.


The board offers a generous number of thermocouple, pressure, analog signal, and rpm timer inputs, with a similarly generous array of PWM speed control, servo driver and higher current DC switched outputs.  Networking to other devices is supported via USB, serial, SD card and CANbus (the networking standard for contemporary engine systems).   These features operate on top of a powerful native processor for stand alone operation, with a 4 line screen included for in situ instrument reading without a computer monitor.  

Internally at ALL Power Labs, we use this board to generate datalogged test results like this.




The GCU is uniquely suited for research applications that need robust and integrated instrumentation and datalogging.  It is equally relevant for industrial applications where sensor input is used to control various motors, solenoids, fans and other control devices.  In both cases, our goal is to provide the type of expert sensing and control solutions usually only found for 10s of thousands of dollars through scientific or industrial equipment suppliers.  The GEK GCU offers equal or superior features for $1395 with the "full fill" version, or $695 with the "half fill" (see details below).  Most will probably realize that just the 16 channel thermocouple reader to serial or usb interface would cost this much from a typical scientific supplier. 


The GEK GCU is based on an Atmel AVR processor, with Arduino compatible firmware and software installed on top.  This allows us to leverage the tremendously large user base and code libraries of the Arduino environment, though deployed over a richer measurement and control base than typical Arduino projects.  Power and ease of use, together at last-- all in the service of the "Cult of the Black Goo".


Here are the specific details of the full and half fill versions:



  Full Fill
Half Fill
Atmel ATmega 1280
Atmel ATmega 1280
Atmel ATmega 1280
Thermocouple Inputs
16 K-type
6 K-type
4 K-type
Pressure Inputs (High Range, +/- 28 inH2O)
Pressure Inputs (Low Range, +/- 8 inH2O)
FET Outputs (5 A continuous)

Analog Inputs

(10-bit, Phidgets  compatible connectors)

Frequency Counter Input
R/C Hobby Servo Outputs 3 3 1
Display (4x20 character) yes yes yes
4 Button Keypad yes yes no
MicroSD Slot yes no  
CANbus hardware yes no no
RS-232 Interface yes yes no
Prototyping/Expansion Area yes yes yes



User's Manual

v 0.6 - draft form (pdf)

GCU Part Positions




//install libraries in Arduino application folder/hardware/libraries/KSlibs.

KSlibs - Arduino support libraries


Note (the function GCU_Setup should be placed inside setup() with values to properly specify the GCU in use):

  //version = V2 or V3 / 2.0 or 3.0
  //psequence: for V3.01 boards, check sequence of P sensor part numbers (e.g. MXP7007 or MXP7002, and use last digit to form the sequence e.g. P777222 or P222777). V3.02 boards use P777722.



//Install sketches into the Arduino folder (Windows: My Documents/Arduino; Mac: User/X/Documents/Arduino)

//In the Arduino interface you will see these sketches show up under File/Sketchbook.

KS_Datalogging - Arduino sketch

KS_Testing - Arduino sketch for running tests(with PID pressure control)

KS_Engine3 - Arduino sketch for running Power Pallet (includes energy monitoring code, PID O2 control, alarm code) (note: when downloading from GitHub, you will need to rename the sketch "KS_Engine3")


Recommended Additional Libraries

You may want or need to install additional libraries, depending on the code you want to run:



Code Examples

GCU Example Code


Communication and Datalogging

A serial terminal can be used to communicate and datalog with a computer:

  Windows: puttytel

Datalogging/Graphing Application for the PCU/GCU (Windows)

  Mac: terminal

  How to do datalogging with the GCU

  Process Control and Visualization Software



Power Monitoring

AC Power Monitoring

OpenEnergyMonitor Library

Flow Measurement

Orifice Flowmeters: Building and Calibrating an Orifice Flowmeter & Code

APL Research Kit


Humidity Measurement 


Current Measurement 


Temperature Measurement 


Force Measurement 


Voltage Measurement 



Working with Inductive Loads

Using inductive devices (motors, relays, solenoids...) with the GCU



GCU Can-Bus Support


Menu Screens

The basic software that comes with the GCUv3.0 has five data screens displayed on the LCD. 

1)Main Menu



4)Fet Drivers

5)Servo controllers



More pictures of GCU v3.0.


Bill of Materials

BOM: PCU3.02BOM.xls




If you would like to place an order for the GCUv3.0 visit the instrumentation page in the GEK gasifier store.



  1. Q: The Arduino compiler states: "Error: DDRJ was not declared in this scope." A: Confirm that the Arduino Mega board is selected from the Arduino->Tools->Board menu. 

2.  GCU: Getting Started (pending)



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