This application provides wireless control for up to 256 devices. The sensors are wireless and transmit to the controller when a change in the environment is detected. The controller operates the devices by using pre-existing power lines via X-10 eliminating the cost of installing wires for communication. It can be used in several applications for controlling the environment. Two applications are described here. One proven application would be to control the lights in a museum. The idea would be to intensify a light when a patron moves in front of a display, and dims a light after the patron moves away from the display. Another application would be to control the environment in a green house by monitoring the temperature and the humidity and turning fans or heaters on or off to get the desired temperature.

The RF sensor monitors a specific task and, if that task was completed, it then transmits the address of the RF sensor, and whether the device being controlled is a lamp module or an appliance module to the Zilog Z80180 MPU (main processor). The RF sensor determines it's X10 address by reading digital inputs configured with jumpers. It also reads a digital input to determine if it is going to control a lamp or an appliance module. In the museum application, the RF sensor would be an infrared sensor to detect the heat of a person's body. If there is enough heat present, then the RF sensor transmits the address of the RF sensor that was tripped. When the sensor sees that there is not enough heat present, it then transmits the RF sensors address again. The RF sensor can be made to fit specific applications for the user's needs. A few examples would be a temperature sensor, a real-time clock sensor, a motion sensor or a humidity sensor.

The Zilog Z80180 MPU is used to receive the RF signal from the RF sensor and converts it to X-10 commands sent to the TW523. The TW523 handles all of the timing to transmit over the power lines to X-10 devices. The RF sensor's address corresponds to the House Code and Unit Code of the device that needs to be controlled. The main processor keeps track of whether the device was last turned on, off, dimmed or brightened. If the device being controlled is using a lamp module then the main processor turns the lamp on by using the bright command and turns the lamp off by using the dim command. If the device being controlled is an appliance module then it just turns the device on or off. If the user only has lamp modules and wants to just turn the lamp on or off then the sensor would be configured as an appliance module.

When the main processor is powered up it assumes that all of the units are in the off state. This is how different RF sensors can be interfaced with the main processor without having to write new code each time a different sensor is interfaced to it.

Parts Used

For developing this application I used an OEM board called the RTC180. This general-purpose processor board uses the Zilog Z80180 processor running at 9.216-MHz. The board operates at +5V. It is capable of having up to 96K of system memory. The following is a block diagram of the RTC180.