Abstract: A portable, low profile electric radiant heater has an elongated heating element. A plurality of thermistors are disposed proximate to and along the length of the elongated heating element, spaced at substantially equal intervals. A microcontroller switches a reference resistor in series with a charging capacitor to determine a reference timer value. The microcontroller switches banks of multiple thermistors in series with the charging capacitor to determine associated timer values. The microcontroller calculates thermistor resistance values using the reference timer, reference resistor, and thermistor timer values. A lookup table is employed to determine a temperature value associated with the thermistor resistance value. This serves as the sensed temperature of the associated bank of thermistors. A plurality of tip-over switches are provided. One tip-over switch is disposed between the microcontroller and the heating element.

Abstract: An electric radiant heater has a proximity sensor capable of detecting the presence of an object proximate the top surface of the heater's housing. The heater also has a temperature sensor capable of sensing ambient temperature proximate the top surface of the heater's housing. A microcontroller is coupled to the proximity and temperature sensors. Upon the detection of an object atop the heater's housing, the microcontroller determines if the temperature sensor's output is indicative of the presence of ice or snow. If so, a heating element of the heater is allowed to remain in operation. Otherwise, the detected object is considered to be potentially combustible material, and the heating element is switched off by the microcontroller.

Abstract: An electric radiant heater has a proximity sensor capable of detecting the presence of an object proximate the top surface of the heater's housing. The heater also has a temperature sensor capable of sensing ambient temperature proximate the top surface of the heater's housing. A microcontroller is coupled to the proximity and temperature sensors. Upon the detection of an object atop the heater's housing, the microcontroller determines if the temperature sensor's output is indicative of the presence of ice or snow. If so, a heating element of the heater is allowed to remain in operation. Otherwise, the detected object is considered to be potentially combustible material, and the heating element is switched off by the microcontroller.

Abstract: A portable, low profile electric radiant heater has an elongated heating element. A plurality of thermistors are disposed proximate to and along the length of the elongated heating element, spaced at substantially equal intervals. A microcontroller switches a reference resistor in series with a charging capacitor to determine a reference timer value. The microcontroller switches banks of multiple thermistors in series with the charging capacitor to determine associated timer values. The microcontroller calculates thermistor resistance values using the reference timer, reference resistor, and thermistor timer values. A lookup table is employed to determine a temperature value associated with the thermistor resistance value. This serves as the sensed temperature of the associated bank of thermistors. A plurality of tip-over switches are provided. One tip-over switch is disposed between the microcontroller and the heating element.

Abstract: A combined arc fault circuit interrupter and leakage current detector interrupter. A current sensor, amplifier, and comparator are employed to detect the presence of leakage current in alternating current power conductors. Upon the detection of an amount of current leakage beyond a threshold level, a relay is opened, disconnecting a source of AC power from a power conductor being monitored, such as an appliance line cord. An arc sensor, envelope detector, amplifier, and microcontroller are employed to detect the presence of an arc fault in the alternating current power conductors. The arc fault detection algorithm implemented by the microcontroller is capable of discriminating between high frequency noise which is not caused by a parallel or series arc fault, with high frequency anomalies which are the result of arcing.

Abstract: The present invention relates to a portable, personal breath tester device for testing the blood alcohol content of the user of the device. The breath tester comprises a circuit board, wherein a sensor, a liquid crystal display, and a processing unit are installed on and electrically connected to the circuit board. The processing unit receives a voltage signal from the sensor representing the blood alcohol content of the user and converts the voltage signal to a precise value that is displayed on the liquid crystal display.