This paper presents a new design of a low cost, two channel, type K thermocouple interface circuit for microcontrollers. This interface circuit enables the connecting microcontroller to make accurate temperature measurements from 0 up to 250 degree Celsius with 1 degree resolution. The usage of the microcontrollers' computational capabilities is proposed to make an adaptive self-calibration for the designed interface circuit. These capabilities are also used to solve the two major problems associated with thermocouple signal measurement: the thermocouple non-linearity problems; and the thermocouple reference junction problems.