[london-hack-space] Hipsterbot conversion

[Glen]

These are my notes detailing the conversion of the Hipsterbot from
original electronics to an Arduino mega.

An RAMPS 1.2 board is being used as an interface between the Arduino
and the Makerbot cupcake. Two changes are needed, an alteration to
take readings from the heated bed's thermister and an interface to
connect the existing stepper motors to the sockets where Pololu
stepper drivers should be.

The heated bed has five pins, a set of two take 12 volts to the
heating element and a set of three for the 100K ohm thermister. The
Thermister pins (counting from the closest pin to a corner) are:
Ground, 5 volts & signal. The 5 volt and ground leads can be connected
directly to the PSU. The Signal pin should be connected to analog pin
8, near where the print head thermister connects. A change in the
firmware is needed to use this pin.
In the pins.h file of the RAMPS firmware.
#elif MOTHERBOARD == 3
.
.
.
#define TEMP_0_PIN 2 <-- Change this line to this -> #define
TEMP_0_PIN 8


Stepper driver adaptor.

There are three pins that need to be bridged from the Pololu sockets
to the Makerbot stepper controllers, these are: enable, step &
direction.
The enable pin is closest to where the 12 volt supply for the board is
attached. Direction is on the other end of that row of pins. Step is
next to Direction, one pin towards Enable.

( ) !EN
( ) ( )
( ) ( )
( ) ( )
( ) ( )
( ) ( )
( ) !Step
GND Direction

Connect these using jumper wires to the ribbon cable from the makerbot
v2.3 stepper controller.

(1) GND
step Dir
en (6)
(7) (8)
(9) (10)



Other firmware changes
Disable endstops in configuration.h
//Endstop Settings
#define ENDSTOPPULLUPS 1
const bool ENDSTOPS_INVERTING = false; <-- Make this true
const bool min_software_endstops = false;
const bool max_software_endstops = true;
const int X_MAX_LENGTH = 220; <-- Change these to match the print
area.
const int Y_MAX_LENGTH = 220;
const int Z_MAX_LENGTH = 100;



Other wiring
The three 12 volt connections next to the USB cable, listing from
closest to the cable, are:
hot-end heater,
fan or conveyor belt &
Heated bed