What
This was a team project for our Junior Design class where we were tasked with designing a battery powered ESP32 that measured something and displayed it. Two other students and myself worked together on this project and we decided to use a MPU-6050 to measure acceleration and rotation. We chose to display the readings on a 16x2 LCD screen in real time.
How
We used a 9V battery as our power source for the ESP32, however, the ESP32 ideally takes an input of 5V so we designed a 5V LDO linear regulator circuit to take 9V in and output 5V. From there it was a bunch of soldering, getting the power connected for the ESP32 then connecting the sensor and LCD display. With all of our hardware setup, we used the arduino IDE to program our ESP32 and display acceleration and rotation data on our LCD. Our final design included a box to hold all of our components and power switch to toggle the power for the ESP32.
Reflection
One challenge we faced in the 5V voltage regulator circuit was the output voltage falling below spec at higher current draws, even though the current draw was within spec. After some testing we determined we need bigger capacitors on the input and output to smooth the voltage which led to a much more consistent 5V output. Something we would use in the future if redoing the project is a buck converter as they can be much more efficient power wise which is very important for battery powered systems.