The following information is growing out of the Gasifier Monitor. The case has been enlarged and a number of functions have been added. Code files are available at the bottom of the page.
Additions to the Gasifier Monitor.
Code to read an oxygen sensor placed on the exhaust of the engine being run on wood gas.
Servo code added to control an air mixing valve to control the air/wood gas mixture either manually or based on O2 sensor readings.
Code changes to monitor four thermocouples, the original two for the gasifier body and two more for the cyclone and filter/cooler outlets.
Code and controls to control a blower's speed. Currently for 110 volt vacuum blower but with easy conversion to a 12 volt blower when it arrives.
Addition of an Infrared sensor and Infrared Remote control.
LCD screens to monitor thermocouples (2), O2 sensor (1), blower speed (1), air mixer(2)
Added a settings.h file to make it easier to make changes to settings that other people using the software might need to make.
Inside the controller box
This looking down into the controller box without the cover in place. The top left is an 110 volt outlet with a 9 volt dc power supply for the Arduino. Below that in gray is a 30 amp solid state relay for the blower fan. It is controlled by a PWM pin on the Arduino to do speed control.The LCD screen is in the middle between the outlet and the relay.
The center of the box has the Arduino UNO on the bottom with a 4 thermocouple board on that with a connector shield above that. The whole base of the box has a 1/4 Lexan sheet. The Arduino is mounted on another smaller sheet that can be removed so the ArduinoUNO board once detached from the thermocouple shield can be brought into the house to upload new coding without disconnecting 27 wires. The differential pressure sensors are in the bottom right and have not been mounted yet. O2 sensor wires and the servo motor wires are also not connected in this photo. The orange cords are for 110 volt in and 100 volt out for the blower.
In addition to the files listed below these library files will also be needed from the Gasifier Monitor page.
The solid state relay being used is a zero crossing unit. This allows the SSR to turn on and turn off at the zero point on the sine wave of the AC power. The harmonics of the 60 Hz AC and the PWM signal along with the zero crossing does cause some speed levels to be a bit rough.