Comments on: Flash Bang Motherboard

By: Giles Bathgate

Giles Bathgate — Wed, 23 Jun 2010 08:22:33 +0000

Thanks wade, I agree that the extruder controller can be used to drive a stepper, but for me its like using a hammer to put in a screw. It works, and in some cases it can be better, it all comes down to personal preference in the end. In general I feel that the makerbot electronics will be superseeded by electronics that are more readily available such as the Arduino Mega and Pololu combination Once OverlapStrap is running on belts, the first parts Intend to build are parts for your "Wades" extruder

By: Wade

Wade — Wed, 23 Jun 2010 07:35:34 +0000

With a bit of tuning, and some gearing, the extruder controller works pretty well as a stepper driver – I’ve got two of them running now, and have printed a Mendel with them. The trick is to set the PWM low enough that you don’t cook your steppers – it’s not like we’re trying to drive the extruder stepper anywhere near it’s top speed (where a proper stepper driver would really help). You can also crank up the PWM frequency if the 1 kHz noise gets to you – there’s some notes in the firmware code about how to do it, although they are a bit confusing.

Using a Nema17 stepper for the extruder is pretty overkill though – we should probably be using much higher gearing and a much smaller stepper, to keep the weight and cost down. But for now it works.

Wade

By: Giles Bathgate

Giles Bathgate — Tue, 22 Jun 2010 09:43:08 +0000

I should have looked harder for that vital bit of information, and I would have saved myself a headache. I notice you also connect the signal gnd. I should probably do the same as I am currently just relying on the gnd from the power source.

By: Unaimed

Unaimed — Mon, 21 Jun 2010 20:21:08 +0000

I'm using a stepper controller for the extruder as well. I took a picture of the connections, see here