This will detail and record the progress of building a 16+ Channel exhaust-gas and cylinder-head temperature display using a graphic LCD display, Atmega328P, Arduino IDE & libs, LTC2995 ADC and K-type thermocouple probes. The project consists of two or more PCBs.
The display head with the TFT and a rotary knob user interface is mounted in a 3 1/8" standard round aircraft instrument hole (or similar) in the aircraft instrument panel. It connects to the data acquisition PCB via a 6 pin cable using modular connectors and a slowed down i2c bus.
The data acquisition has screw terminals for the K-type thermocouple sensors , contains the ADC converters and can be mounted in a convenient, accessible place on the firewall. Multiple acquisition boards can be stacked for more inputs. a single board provides 6 differential channels for thermocouples and 4 single ended inputs for ground referenced voltage signals. The design tolerates shorted probes to aircraft chassis ground without false readings.
The division between display and measure head is to ease the installation and connection of the stiff thermocouple wires that otherwise usually have to be extended and brought all the way to the back of the instrument panel, making it hard to install and maintain.
