stm32f103 bluepill 3D printer control board

A 3D printer control board based on stm32f103c blue pill board. * Single 12-24V voltage input * 4 slots for stepper motor drivers * 3 MOSFET outputs for bed, heater and cooler fan * 3 inputs for end-stops * 2 inputs for temp sensors * 3 non-regulated outputs with supply voltage (e.g. for additional coolers, LEDs, etc) * connectors for standard RepRap Smart Discount controller * I2C connectors (e.g for I2C LCD) * Reverse voltage protection (a reverse connected diode which'll blow the fuse in case of wrong polarity) * One-side PCB, convenient for DIY Can be done with minimal efforts (1 side PCB). Based on low cost components (the MCU is just a cheap replaceable BluePill board). Sources can be found here https://github.com/xl0e/Marlin-BluePill (the bluepill_sample_delta branch with delta printer sample configuration). The environment is already preset for this board. Refer to Configuration.h file for your printer settings and the pins_CUSTOM_BLUEPILL.h for pins definitions. [!] The low-level voltage source for this board is a standard LDO therefore in case of 24V input voltage it's quite tough for LDO to dump 19V voltage difference. I tested on my board with L7805 by ST. It heats up to 60-70C which is acceptable but additional heatsink is preferred.