However many air-conditioner wall units have no interconnections provided and usually utilise a proprietary infra-red contoller with some functions provided by step buttons hidden beneath a panel on the unit.
The circuitry to drive these varies significantly and custom interfaces would need to be designed.
Most aircon units have one thing in common. That is an LED display indicating the operational status of the functions provided. Some of these LEDs are lit using a DC current and others are fast switched by polling software derived from an internal processor.
TCC have designed an interface card which when connected to the LED leads provides an isolated status point and isolated start signals.
According to the functional operation of the air-con unit and the facilities provided by the home automation unit adequate of the aircon can be obtained by Home Automation without interfering with the normal I/R control.
Currently this unit is successfully used interfacing McQuay International (OYL, YORK) airconditioning systems to the "SMART" JEEVES Home automation systems.
The PCB is 80 x 80 mm Square and subsequently fits inside most aircon wall
units and meets safety barrier requirements. It can be connected via a simple
four core telephone cable back to the HA control unit.
The applications can be applied to smaller offices where Split aircon is
used and can then be controlled by card access system either by access
in the morning and egress at night or by time zone.
It could also be used coupled to a building management system for the odd
areas which employ split aircon and which is not normally controlled directly
by a Building Management System.
