Foreword

In response to the spreading of the coronavirus epidemic, forehead thermometers have become necessary tools for families and public places. Since measurement does not require body contact, the chances for virus infection has been reduced, and the temperature can be measured within seconds through the infrared sensor; it also became very popular because it is extremely easy to use.

Solution features

When the button is pressed, the forehead thermometer will measure and collect the temperature through the infrared sensor, and convert it into high and low levels; the ADC inside the sensor can convert the signal into numbers, and the microcontroller can read the temperature through the serial port. The ML51 released by Nuvoton can easily realize the product solution. The ultra-low power consumption of the ML51 series is equipped with multiple power modes; the operating voltage when measuring temperature is 80uA/MHz, and it is less than 0.8uA during sleep mode; its quick wake-up mode with less than 10uS can wake up the main control immediately and enter the operating mode. The low-power feature allows ear thermometers to only require a CR2032 button battery and that will be enough for 10,000 uses. The ML51 provides 12-bit ADC and is equipped with an internal reference voltage that can provide more accurate voltage levels to the ADC, and the measurements will not be affected even as the battery loses power. The ML51 is equipped with 1.8V to 5.5V reference voltage, able to connect to 3V or 5V voltage LCD screens that can be boosted by the internal LDO, making it more flexible for peripheral connections.

Introduction to the core

• The ML51 series provide over a dozen models and their pins are compatible, bringing convenience to customers’ future product upgrades
• Provides 1.8V~5.5V wide operating voltage that can adapt to the operating voltage of multiple products
• Equipped with 12-bit high precision ADC that can provide better accuracy for measuring battery power
• As many as three channels of UART that can be used to connect multiple modules
• ESD 8KV & EFT 4.4KV high anti-interference capability
• Provides small packages making it suitable to be used on handheld devices with limited circuit board space