q3k's Pullstruder

PET bottle recycling machine. Based on the Recreator3d by Joshua R. Taylor, but with a few twists.

Work in progress.

Electronics

Mainboard is a Melzi 'v5.0' with an ATMega1284P. Reused from a TRONXY X1.

Schematic of 2.0: https://reprap.org/mediawiki/images/7/7d/Melzi-circuit.png

EXP connector:

On the mainboard:

PC1 | 1  2 | PA1
PC0 | 3  4 | PA2
PD3 | 5  6 | PA3
PD2 | 7  8 | PA4
VCC | 9 10 | GND

LCD board

EXP Pin	AVR Pin	AVR Function	Screen board function
1	PC1	I2C SDA	LCD D7
2	PA1	ADC1	Button Matrix
3	PC0	I2C SCL	LCD D6
4	PA2	ADC2	LCD EN
5	PD3	INT1	LCD D5
6	PA3	ADC3	LCD RS
7	PD2	INT0	LCD D4
8	PA4	ADC4	Unused?

Button Matrix

On the LCD board.

Based on a voltage divider between button(s) pressed and a constant pull-up to VCC.

Resistor to VCC: 4.7k

Button	Resistor to GND	Voltage when pressed (VCC=5V)	ADC Value
Left	470	0.45V	93
Down	1k	0.87V	180
Menu	2.2k	1.6V	326
Right	4.7k	2.5V	512
Up	10k	3.4V	697

Firmware

In progress, written in Rust. Aims to be purpose-specific and not just a repurposed 3D printer control firmware.