I'm working on a portable project using an Arduino pro mini (Atmega328 3.3V 8MHz) that needs to: receive GPS and magnetometer data, process and display this data on 7 segment and OLED displays, save logs to a microSD card, and have few buttons to press.
Since it's portable, I'm powering it with a single 18650 battery that is connected to RAW pin. I'm using a small DC-DC converter to 5V for MAX7219 and 7 segment displays. All other components are running from VCC pin.
Below is my circuit diagram (sorry if it's messy, I hope you can read it), along with pictures of exact modules I plan to use. I'd love your feedback on whether I've wired everything correctly or if there's some better approach. I'll also provide the Arduino pro mini pinout diagram I followed.
List of modules and components on diagram:
Mini DC-DC converter 0.9-5V to 5V
FST 18650 battery 3.7V 2200mAh
MAX7219 8 digit 7 segment LED display (x2)
GY-271 QMC5883 magnetometer
Buttons (x4)
Arduino microSD card module 3.3V
OLED display 0.91 128x32 px
Ublox NEO-7M GPS module
If you need more details or clarification feel free to ask. Thanks!
You need to wire one component at a time and get that working, electrically and in software before connecting a second and so on .
Your buttons won’t work without pull-down resistors - better to use INPUT_PULLUP and switch inputs to 0v.
I’d suspect that battery won’t be able to power all those parts .
Why have two displays? 7 seg displays are very power hungry .
It would be better to say what you are trying to do, how long it’s supposed work etc .
