A reference design for a SpO2 meter, this device can help you find your blood oxygen saturation level in real-time. 
MAXREFDES1043 hardware top (above) and bottom (below)
Since the inception of COVID pandemic, one tool that helped monitor the state of patients’ health was a SpO2 meter. But when any serious global event takes place, so, for a short time the availability of essential equipment decreases, which leads to overpriced and low-quality counterfeit products flooding the shelves of both online and physical shops. The same was the case for the blood oxygen meter, which soon ran into short supply.
So, in this article, we will discuss MAXREFDES1043, a SPo2 measurement device by Maxim Integrated’s. The MAXREFDES1043 uses a new-generation biosensor, MAX30102 to measure the blood oxygen level. The highly integrated sensor features LEDs, photodetectors, optical elements, and low-noise electronics with ambient light rejection, thus simplifying the design and reducing the BoM component number and price.
The main features of this reference design are it’s low power consumption, small form factor and high accuracy, moreover, the device can detect heart rate by modifying the firmware without needing to make any major hardware changes. The design also features an OLED screen to display the measurement. The MAXREFDES1043 features an STM32L432KC as its microcontroller. It is powered by a small battery ranging between 90mAh – 120mAh. The size of the battery is restricted by the small size of the device.
The reference design has two modes of operation: standby mode and operation mode, when the finger is not placed on the optical sensor the device works in the standby mode. When the optical sensor detects the presence of the finger, it switches on the operation mode which then measures and displays the amount of saturated oxygen in the blood.
The reference design has been tested and verified. To read more about this reference design you can visit the company’s website. To simplify the designing process, Maxim Integrated as provided the complete set of design resources including schematics, bill of materials, PCB layout, and test files, which can be downloaded from here.
