Pololu Extruder Stripboard
The idea is to make a dead simple stripboard mounted Pololu stepper driver board and connect it to the existing RepRap electronics in order to bypass the noisy inefficient 2 H-bridge hack on the extruder controller (at least until an all Pololu Electronics PCB design matures).
|1||$1.00||12 Way 6A PVC Terminal Block (only need 4 way, so cut 4 off)|
|1||$0.07||2 Pin .100" Straight Male Polarized Headers|
|3||$0.30||4 Pin .100" Straight Male Polarized Headers|
|3||$0.51||4 Pin .100" Polarized Header Connector|
|2||$1.20||Crimp Pin for Header Connectors (need 14)|
|2||$0.32||8 Pin .100" Straight Female Headers|
|1||$0.15||2 Pin .100" Polarized Header Connector|
|1||$0.95||Stripboard - Small (cut in half)|
|1||$0.08||100uF 25V Radial Electrolytic Capacitor|
|1||$0.10||100ohm 1/4W 5% Carbon Film Resistor|
|1||$12.95||Pololu stepper driver board|
Split 12v Power
12v needs to split. Half goes to extruder controller for the heater, etc. The other half goes to the new Pololu board. Do the split just like you do for the power plug on your Mendel.
Solder Stripboard Mount
C1 is a 100uF, make sure - connects to GND and + to the Pololu. R1 is a 100ohm resistor.
On the bottom right in the picture a 4 pin header is used, but only 2 pins are needed there for the 12v and GND
4 pins on top right corner of motherboard. 5v, GND, SDA (to STEP), and SCL (to DIR) on Pololu board. 12v and GND from cholocate block split above. Make sure you cross over the SCL and SDA wires to the DIR and STEP pins on the stripboard since the Pololu board's 4 pins are in a different order.
In motherboard firmware's configuration.h change E0_STEPS_PER_MM to 32 for 1/16 microstepping.