Saturday, 31 January 2009

Alternative Electronics mounting

After looking at the darwin, and winding it up and down a few times, I found there is quite a lot of dead space inside the frame at the bottom. The z-axis cannot travel all the way to the bottom, because the motor and belt assembly prevent it.

With a bit of measuring, I found that the PSU and the electronics could be fitted inside the dead space.

I cut a chunk of plywood to size that would take all the PCBs. I found some non-conductive solid foam in the garage, and cut a couple of strips. Sticking the strips along the plywood, the PCBs can be mounted with some small bolts, without the undersides of the PCBs touching. The plywood and PSU are mounted to the frame with cable ties. They seem to be holding things together pretty well so far.

The x and y steppers leads were too short, so I extended them with some 4-core speaker cable and re-attached the plugs. The extruder leads I also extended, giving it plenty of slack to move around and reach to the PCBs. The power supply leads are now situated right near the PCBs so they plug straight in.

The biggest risk is a stray cable being caught up in the belt and either being ripped out or jamming up the belt. Make sure all cables are securely attached with cable ties and can't touch the belt. I routed all mine along the outside, underneath the lower sqare of rods and then direct to the sockets. The arduino is tucked away pretty much in the center of the space.

This arrangement protects the electronics and means that from the outside, all you need is the USB cable for the arduino and the power for the PSU. I think it also looks slightly neater than the boards on the outside, but since the Darwin is unlikely to win any beauty awards (only engineering ones) it probably doesn't matter too much :-)

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