Wireless sensor having a variable transmission rate

A load control device for controlling an electrical load powered by an AC power source in a load control system having a sensor for measuring a parameter, the load control device comprising:

• a controller for controlling the electrical load;
• and
• a wireless receiver for receiving wireless signals from the sensor;
• wherein the controller is operable to decode a present value of the parameter and one or more estimators from the wireless signals received from the sensor, the controller operable to determine at least one estimated parameter value using the present value of the parameter and the estimators, and to control the electrical load in response to the at least one estimated parameter value.

A load control system for controlling an electrical load located in a space of a building, the load control system comprising:

• a load control device for controlling an electrical load;
• and
• a sensor for measuring a parameter, the sensor operable to transmit wireless signals to the load control device in response to the parameter, the load control device operable to control the electrical load in response to the wireless signals received from the sensor;
• wherein the sensor is operable to determine a first predicted value of the parameter and to calculate an error using a present value of the parameter and the first predicted value of the parameter, the sensor operable to transmit wireless signals to the load control device if the error is too great.

A method of transmitting a digital message in response to a value of a parameter, the method comprising:

• generating a control signal representative of the value of the parameter;
• periodically sampling the control signal to generate at least one sampled parameter value;
• determining at least one predicted parameter value;
• calculating an error using the at least one sampled parameter value and the at least one predicted parameter value;
• and
• transmitting a wireless signal if the error is too great.