Stripboard stepper driver carrier board
Stepper driver board
I haven't ordered one of the stepper driver shields, so instead I've designed a stripboard layout to assist with the wiring. I will use solder posts to connect wires to the board.
- NOTE 1: I found that I have to set $7=200 in the Grbl settings to get the motors to move in the right directions.
- NOTE 2: This design has been tested with a ShapeOko.
- NOTE 3: It appears that some electrical noise is being picked up during the first second or two after resetting the Arduino. I'm guessing that during this brief period, the Arduino pins haven't been switched to outputs, so they're high impedance, making the stepper driver inputs more susceptible to noise. I have adjusted the design by changing the pull-down resistor attached to the !enable inputs into a pull-up resistor instead, and this appears to have resolved the problem.
- NOTE 4: I have added an adjusted board layout with better power supply isolation - see below.
The 47uF capacitors are a bit larger than I'd guessed, so the ground bus-bar had to take the scenic route on my board. I've adjusted the design to allow more room so that others don't have that problem.
Here is an updated version with better logic/motor power supply isolation and better motor current handling. Warning: this design is untested.
You will need two 0.1uF ceramic capacitors in addition to the three in the parts list below.
The wires that run parallel to the tracks on the track side have been added to carry the higher motor current, and could be actual wires or just a thick coating of solder.
|Stripboard, 27 strips of 18 holes long||1||stock|
|Header pin socket row, 24 holes long||2||I cut down a 40-way socket||Ebay, not great quality so I won't link to it|
|Solder pins||23||I used header pins||see above|
|Pair of header pins||9||see above|
|Header pins, for plugging in to Arduino||9||1x row of 6, 1x pair, 1x individual||see above|
|Jumpers for header pins||9||If not using 16x microstepping then you'll need less!||Maplin code N23AN, http://www.maplin.co.uk/2.54mm-0.1-inch-miniature-pin-jumpers-34146|
|Solid wire for “bus bars”||~40cm||low current, so thin is ok||stock|
|47uF 50V electrolytic capacitor||3||A lower voltage rating would be ok (>= motor voltage)||Maplin code VH33L, http://www.maplin.co.uk/radial-electrolytic-capacitors-13472|
|0.1uF ceramic capacitor||3||marked 104K||stock|
|Polulu A4988 stepper driver carrier, and header pins||3||http://www.hobbytronics.co.uk/a4988-stepper-motor-driver?keyword=a4988|
|Motor hook-up wire||18m?||Thick enough for 1.5A||stock|
|Motor power hook-up wire||1m?||Thick enough for 4.5A|
|Logic hook-up wire||9x 10cm?||I used some ribbon cable||stock|
|Terminal block||12 way||So that motor wires can be attached/detached without soldering.||stock|
It would be very straightforward to extend this layout for four drivers. If anyone wants the original OpenOffice Draw files (no, really, I used OpenOffice Draw) to do that, let me know.
It ought to be possible to connect one of these to a parallel port and drive it from EMC or other PC CNC software.
The stripboard stepper driver carrier board has been successfully constructed and used by: