No major progress since my last post but I have done a few little bits here and there. I thought it might be a good idea to kind of copy-paste from some of my notes...

8 Nov 2018

I've managed to kill the RGB LEDs! Not sure how, but I was reassembling the head controller and wiring and couldn't get a response from them even using known-good code. I'm hoping it's just the first one in the string that is dead and I can cut it out. Need to revisit this in the future.

18 Nov 2018

Bought a little "NEO-6M" GPS module GY-GPS6MV2 for a crazy £3.89!
I wanted to try it out and it works as expected. I used http://freenmea.net/decoder to help make sense of the serial output.

26 Nov 2018

CCW head rotation now working on negative target input from serial. Dev code did CW and CCW but couldn't start in CCW direction. Just needed tweaking.
I also added manual steering via a pot (and mode select switch), just for development purposes/fun.

16 Dec 2018

Started work on power distribution; an aluminium box with busbars, fused outputs and, eventually, some sub-circuit isolator switches. Drilled large cable access hole and fitted rubber cable grommet. Mounted to main box-frame.

20 Dec 2018 

I designed and printed an e-stop shroud to protect it from accidental bumps and as a guinea-pig for trying Frog tape on clean bed for first time. I've been using ABS slurry on the bed but my prints have been a bit iffy recently so wanted to experiment. 

More tweaks to my camera pitch-roll mount with 9g servo models inserted. Need short ball-link rod ends to complete: on order from China (eBay).

Worked on another 3DP front panel design (again). Will include a 1602 orange on black LCD when it arrives from China. Couldn't find a 20x4 at a reasonable price, considering it's mostly for fun.

27 Dec 2018 - Printer maintenance and quick PETG trial

Cooling fan on printer PSU was very noisy and on its last-legs. Replaced fan and tightened-up all screws on printer body.

ABS 2cm test cube, 1mm wall at "normal" 0.15mm layer height:

1. 235°C/100°C - had slight baggy corners at bottom, lumpy-snotty rear corner. 
2. 230°C/80°C + fan (but no duct) - better corners, no sagging.
3. 230°C/80°C + fan & duct - as #2 but slightly more bottom warping (curl).

PETG 2cm test cube, 1mm wall at "normal" 0.15mm layer height: 

1. 215°C/70°C/fan - stock Cura PETG settings. Very good print, but bottom came away quite easily.
2. 2. 230°C/80°C/fan - excellent print! Clean and strong.

I love PETG!