Output devices

LED module

As a first exercise, we prepared a test to measure the power consumption of a module consisting of 50 pcs DC 5V 12V WS2811 Full Color LED Pixel Light Module 12mm 10cm Wires IP68 Waterproof RGB Color Digital LED strings.

This is one of the modules that Pepe will use in his final project. We supplied 5V power using a DC LAB power supply LABPS300SN. The power consumption of the LEDs was 982 mA in total.

Next, we uploaded a code developed by Pepe that keeps three central LEDs permanently illuminated in blue while running a sequential lighting effect on both sides in red and green until all 50 LEDs are fully lit. They remain on for 6 seconds. We used Pepe's custom PCB, which features an external power input that supplies 5V to both the MCU and the LED module. In this test, the MCU was not connected to the laptop’s USB port, meaning all power came solely from the external power supply.

The maximum power consumption recorded was 764 mA.

OLED Display

For the next test, we used a 0.96-inch OLED screen with a 128x64 pixel resolution, based on the I2C SSD1306 driver. Following Luis's recommendation, we first measured the power consumption of the Xiao ESP32C3 without any peripherals connected.

Our power supply indicated a consumption of 23 mA.

Next, we connected the OLED screen. As shown in the attached image, the power consumption increased to 29 mA.

To determine the OLED’s specific power consumption, we inserted a multimeter into the circuit, which measured 3.9 mA, while the total power consumption displayed on the power supply dropped slightly to 28 mA.

Finally, we uploaded a test script to the OLED screen to measure its power consumption when displaying illuminated pixels. The power consumption increased by 18.7 mA, reaching a total of 44 mA, as shown in the image.

Through these experiments, we learned how to measure the power consumption of two output devices that we will use in our final projects.