Introduction Rambo 1.2G is a microcontroller board of 3D printer which integrates the stepper motor, hotbed, extruder, fan driver and thermometry in one. Rambo 1.2G is completely compatible with Arduino in that it adapts the same IC, ATMEGA 2560, with Arduino mega2560. 3 additional resettable fuses are added to Rambo 1.2G to protect it from over current. What’s more, the motor drive current can be controlled with code. The present popular LCDs that Rambo 1.2G supports are smart controller 2004 and 12864. Features: 1. Adopting the IC Atmega2560 and Atmega16u2 that are completely compatible with Arduino 2. 4 interface for thermometry 3. All interfaces of 2560 and 16u2 are broken out for external use 4. 2 channel of sdramps that is compatible with SPI 5. 5 A4982 of 1/16 step size, 1 for X/Y axis respectively, 2 for Z axis, 2 for extruder 6. Every control signal of stepper motor has a test point 7. The step size of stepper driver can be divided by firmware 8. Reserved interface for LCD 9. 5 channel of PWM for extruder control 10. 3 power inputs source that is protected by resettable fuses: 12v 15a for hotbed; 12v 5a for extruder; 12v 5a for stepper motor. 11. PCB is composed of 4 layer of 35um copper sheet Compared with the 1.1b version,Rambo 1.2G has the following updates: 1. Increased ESD (Electro-Static discharge) Electrostatic Discharge in the USB circuit section 2. The logical part of the circuit and MOSFET share the same power supply 3. enhanced anti-interference ability of signals. 4 ADC interfaces (one for hotbed, 2 for extruder and one for thermometry)
5 PWM: 2 for extruder, 2 for fan control and 1 for heatbed
6 interfaces for end stop(X/Y/Z min, X/Y/Z max)which can be connected with mechanical or optical end stop, or hall sensor.